bluuebunny/crossref_metadata_2025 huggingface dataset:
Differences in stomatal responses and root to shoot signalling between two grapevine varieties subjected to drought
Authors: Beis Alexandros , Patakas Angelos
Published: February 2010

A comparative study on stomatal control between two grapevine varieties (Vitis vinifera L. cvs Sabatiano and Mavrodafni) differing in their ability for drought adaptation was conducted using 3-year-old own-rooted plants. The plants were subjected to prolonged drought stress by withholding irrigation water. The relationship between predawn water potential and maximum stomatal conductance indicated significant differences in stomatal sensitivity to drought between the two varieties. Stomatal closure occurred at higher values of predawn water potential in Sabatiano compared with Mavrodafni. No significant differences were found in plant hydraulic conductance and osmotic potential at full turgor (π100) between the two varieties. Leaf and root ABA concentrations increased more rapidly in Mavrodafni compared with Sabatiano at the beginning of the drought period. Furthermore, Mavrodafni also exhibited significantly higher xylem pH values as well as higher stomatal sensitivity to ABA and pH increase compared with Sabatiano. Results suggest that these two grapevine varieties might have evolved different strategies in order to adapt under drought conditions. In particular, the greater ability for drought adaptation in Sabatiano might be attributed to the more efficient regulation of stomatal closure. In contrast, chemical signalling in Mavrodafni seems to be the main mechanism for drought adaptation.
Energetic basis of colonial living in social insects
Authors: Hou Chen , Kaspari Michael , Vander Zanden Hannah B. , Gillooly James F.
Published: February 2010

Understanding the ecology and evolution of insect societies requires greater knowledge of how sociality affects the performance of whole colonies. Metabolic scaling theory, based largely on the body mass scaling of metabolic rate, has successfully predicted many aspects of the physiology and life history of individual (or unitary) organisms. Here we show, using a diverse set of social insect species, that this same theory predicts the size dependence of basic features of the physiology (i.e., metabolic rate, reproductive allocation) and life history (i.e., survival, growth, and reproduction) of whole colonies. The similarity in the size dependence of these features in unitary organisms and whole colonies points to commonalities in functional organization. Thus, it raises an important question of how such evolutionary convergence could arise through the process of natural selection.
Positive selection of a duplicated UV-sensitive visual pigment coincides with wing pigment evolution in
Heliconius
butterflies
Authors: Briscoe Adriana D. , Bybee Seth M. , Bernard Gary D. , Yuan Furong , Sison-Mangus Marilou P. , Reed Robert D. , Warren Andrew D. , Llorente-Bousquets Jorge , Chiao Chuan-Chin
Published: February 2010

The butterfly
Heliconius erato
can see from the UV to the red part of the light spectrum with color vision proven from 440 to 640 nm. Its eye is known to contain three visual pigments, rhodopsins, produced by an 11-
cis
-3-hydroxyretinal chromophore together with long wavelength (LWRh), blue (BRh) and UV (UVRh1) opsins. We now find that
H. erato
has a second UV opsin mRNA (
UVRh2
)—a previously undescribed duplication of this gene among Lepidoptera. To investigate its evolutionary origin, we screened eye cDNAs from 14 butterfly species in the subfamily Heliconiinae and found both copies only among
Heliconius
. Phylogeny-based tests of selection indicate positive selection of
UVRh2
following duplication, and some of the positively selected sites correspond to vertebrate visual pigment spectral tuning residues. Epi-microspectrophotometry reveals two UV-absorbing rhodopsins in the
H. erato
eye with λ
max
= 355 nm and 398 nm. Along with the additional UV opsin,
Heliconius
have also evolved 3-hydroxy-DL-kynurenine (3-OHK)-based yellow wing pigments not found in close relatives. Visual models of how butterflies perceive wing color variation indicate this has resulted in an expansion of the number of distinguishable yellow colors on
Heliconius
wings. Functional diversification of the UV-sensitive visual pigments may help explain why the yellow wing pigments of
Heliconius
are so colorful in the UV range compared to the yellow pigments of close relatives lacking the UV opsin duplicate.
Spontaneous assembly and active disassembly balance adherens junction homeostasis
Authors: Hong Soonjin , Troyanovsky Regina B. , Troyanovsky Sergey M.
Published: February 2010

The homeostasis of adherens junctions was studied using E-cadherin and its two mutants tagged by the photoconvertible protein Dendra2 in epithelial A-431 cells and in CHO cells lacking endogenous cadherin. The first mutant contained point mutations of two elements, Lys738 and the dileucine motif that suppressed cadherin endocytosis. The second mutant contained, in addition, an extensive truncation that uncoupled the mutant from β-catenin and p120. Surprisingly, the intact cadherin and its truncated mutant were recruited into the junctions with identical kinetics. The full-size cadherin was actively removed from the junctions by a process that was unaffected by the inactivation of its endocytic elements. The cadherin’s apparent half-residence time in the junction was about 2 min. Cadherin clusters made of the truncated mutant exhibited much slower but ATP-independent junctional turnover. Taken together, our experiments showed that adherens junction homeostasis consists of three distinctive steps: cadherin spontaneous recruitment, its lateral catenin-dependent association, and its active release from the resulting clusters. The latter process, whose mechanism is not clear, may play an important role in various kinds of normal and abnormal morphogenesis.
Area-specific temporal control of corticospinal motor neuron differentiation by COUP-TFI
Authors: Tomassy Giulio Srubek , De Leonibus Elvira , Jabaudon Denis , Lodato Simona , Alfano Christian , Mele Andrea , Macklis Jeffrey D. , Studer Michèle
Published: February 2010

Transcription factors with gradients of expression in neocortical progenitors give rise to distinct motor and sensory cortical areas by controlling the area-specific differentiation of distinct neuronal subtypes. However, the molecular mechanisms underlying this area-restricted control are still unclear. Here, we show that COUP-TFI controls the timing of birth and specification of corticospinal motor neurons (CSMN) in somatosensory cortex via repression of a CSMN differentiation program. Loss of COUP-TFI function causes an area-specific premature generation of neurons with cardinal features of CSMN, which project to subcerebral structures, including the spinal cord. Concurrently, genuine CSMN differentiate imprecisely and do not project beyond the pons, together resulting in impaired skilled motor function in adult mice with cortical COUP-TFI loss-of-function. Our findings indicate that COUP-TFI exerts critical areal and temporal control over the precise differentiation of CSMN during corticogenesis, thereby enabling the area-specific functional features of motor and sensory areas to arise.
Sequential rounds of RNA-dependent RNA transcription drive endogenous small-RNA biogenesis in the ERGO-1/Argonaute pathway
Authors: Vasale Jessica J. , Gu Weifeng , Thivierge Caroline , Batista Pedro J , Claycomb Julie M. , Youngman Elaine M. , Duchaine Thomas F. , Mello Craig C. , Conte Darryl
Published: February 2010

Argonaute (AGO) proteins interact with distinct classes of small RNAs to direct multiple regulatory outcomes. In many organisms, including plants, fungi, and nematodes, cellular RNA-dependent RNA polymerases (RdRPs) use AGO targets as templates for amplification of silencing signals. Here, we show that distinct RdRPs function sequentially to produce small RNAs that target endogenous loci in
Caenorhabditis elegans
. We show that DCR-1, the RdRP RRF-3, and the dsRNA-binding protein RDE-4 are required for the biogenesis of 26-nt small RNAs with a 5′ guanine (26G-RNAs) and that 26G-RNAs engage the Piwi-clade AGO, ERGO-1. Our findings support a model in which targeting by ERGO-1 recruits a second RdRP (RRF-1 or EGO-1), which in turn transcribes 22G-RNAs that interact with worm-specific AGOs (WAGOs) to direct gene silencing. ERGO-1 targets exhibit a nonrandom distribution in the genome and appear to include many gene duplications, suggesting that this pathway may control overexpression resulting from gene expansion.
Development of the circadian oscillator during differentiation of mouse embryonic stem cells in vitro
Authors: Yagita Kazuhiro , Horie Kyoji , Koinuma Satoshi , Nakamura Wataru , Yamanaka Iori , Urasaki Akihiro , Shigeyoshi Yasufumi , Kawakami Koichi , Shimada Shoichi , Takeda Junji , Uchiyama Yasuo
Published: February 2010

The molecular oscillations underlying the generation of circadian rhythmicity in mammals develop gradually during ontogenesis. However, the developmental process of mammalian cellular circadian oscillator formation remains unknown. In differentiated somatic cells, the transcriptional–translational feedback loops (TTFL) consisting of clock genes elicit the molecular circadian oscillation. Using a bioluminescence imaging system to monitor clock gene expression, we show here that the circadian bioluminescence rhythm is not detected in the mouse embryonic stem (ES) cells, and that the ES cells likely lack TTFL regulation for clock gene expression. The circadian clock oscillation was induced during the differentiation culture of mouse ES cells without maternal factors. In addition, reprogramming of the differentiated cells by expression of Sox2, Klf4, Oct3/4, and c-Myc genes, which were factors to generate induced pluripotent stem (iPS) cells, resulted in the re-disappearance of circadian oscillation. These results demonstrate that an intrinsic program controls the formation of the circadian oscillator during the differentiation process of ES cells in vitro. The cellular differentiation and reprogramming system using cultured ES cells allows us to observe the circadian clock formation process and may help design new strategies to understand the key mechanisms responsible for the organization of the molecular oscillator in mammals.
Language acquisition in premature and full-term infants
Authors: Peña Marcela , Pittaluga Enrica , Mehler Jacques
Published: February 2010

We tested healthy preterm (born near 28 ± 2 weeks of gestational age) and full-term infants at various different ages. We compared the two populations on the development of a language acquisition landmark, namely, the ability to distinguish the native language from a rhythmically similar one. This ability is attained 4 months after birth in healthy full-term infants. We measured the induced gamma-band power associated with passive listening to (
i
) the infants’ native language (Spanish), (
ii
) a rhythmically close language (Italian), and (
iii
) a rhythmically distant language (Japanese) as a marker of gains in language discrimination. Preterm and full-term infants were matched for neural maturation and duration of exposure to broadcast speech. We found that both full-term and preterm infants only display a response to native speech near 6 months after their term age. Neural maturation seems to constrain advances in speech discrimination at early stages of language acquisition.
Disruption of LGI1–linked synaptic complex causes abnormal synaptic transmission and epilepsy
Authors: Fukata Yuko , Lovero Kathryn L. , Iwanaga Tsuyoshi , Watanabe Atsushi , Yokoi Norihiko , Tabuchi Katsuhiko , Shigemoto Ryuichi , Nicoll Roger A. , Fukata Masaki
Published: February 2010

Epilepsy is a devastating and poorly understood disease. Mutations in a secreted neuronal protein, leucine-rich glioma inactivated 1 (LGI1), were reported in patients with an inherited form of human epilepsy, autosomal dominant partial epilepsy with auditory features (ADPEAF). Here, we report an essential role of LGI1 as an antiepileptogenic ligand. We find that loss of LGI1 in mice (LGI1
−/−
) causes lethal epilepsy, which is specifically rescued by the neuronal expression of LGI1 transgene, but not LGI3. Moreover, heterozygous mice for the LGI1 mutation (LGI1
+/−
) show lowered seizure thresholds. Extracellularly secreted LGI1 links two epilepsy-related receptors, ADAM22 and ADAM23, in the brain and organizes a transsynaptic protein complex that includes presynaptic potassium channels and postsynaptic AMPA receptor scaffolds. A lack of LGI1 disrupts this synaptic protein connection and selectively reduces AMPA receptor–mediated synaptic transmission in the hippocampus. Thus, LGI1 may serve as a major determinant of brain excitation, and the LGI1 gene-targeted mouse provides a good model for human epilepsy.
Astrocytic endfoot Ca
2+
and BK channels determine both arteriolar dilation and constriction
Authors: Girouard Hélène , Bonev Adrian D. , Hannah Rachael M. , Meredith Andrea , Aldrich Richard W. , Nelson Mark T.
Published: February 2010

Neuronal activity is thought to communicate to arterioles in the brain through astrocytic calcium (Ca
2+
) signaling to cause local vasodilation. Paradoxically, this communication may cause vasoconstriction in some cases. Here, we show that, regardless of the mechanism by which astrocytic endfoot Ca
2+
was elevated, modest increases in Ca
2+
induced dilation, whereas larger increases switched dilation to constriction. Large-conductance, Ca
2+
-sensitive potassium channels in astrocytic endfeet mediated a majority of the dilation and the entire vasoconstriction, implicating local extracellular K
+
as a vasoactive signal for both dilation and constriction. These results provide evidence for a unifying mechanism that explains the nature and apparent duality of the vascular response, showing that the degree and polarity of neurovascular coupling depends on astrocytic endfoot Ca
2+
and perivascular K
+
.
Genome-wide siRNA screen identifies SMCX, EP400, and Brd4 as E2-dependent regulators of human papillomavirus oncogene expression
Authors: Smith Jennifer A. , White Elizabeth A. , Sowa Mathew E. , Powell Maria L. C. , Ottinger Matthias , Harper J. Wade , Howley Peter M.
Published: February 2010

An essential step in the pathogenesis of human papillomavirus (HPV)–associated cancers is the dysregulated expression of the viral oncogenes. The papillomavirus E2 protein can silence the long control region (LCR) promoter that controls viral E6 and E7 oncogene expression. The mechanisms by which E2 represses oncogene expression and the cellular factors through which E2 mediates this silencing are largely unknown. We conducted an unbiased, genome-wide siRNA screen and series of secondary screens that identified 96 cellular genes that contribute to the repression of the HPV LCR. In addition to confirming a role for the E2-binding bromodomain protein Brd4 in E2-mediated silencing, we identified a number of genes that have not previously been implicated in E2 repression, including the demethylase JARID1C/SMCX as well as EP400, a component of the NuA4/TIP60 histone acetyltransferase complex. Each of these genes contributes independently and additively to E2-mediated silencing, indicating that E2 functions through several distinct cellular complexes to repress E6 and E7 expression.
Agrobacterium
type IV secretion system and its substrates form helical arrays around the circumference of
virulence
-induced cells
Authors: Aguilar Julieta , Zupan John , Cameron Todd A. , Zambryski Patricia C.
Published: February 2010

The genetic transformation of plant cells by
Agrobacterium tumefaciens
results from the transfer of DNA and proteins via a specific
virulence
(
vir
) -induced type IV secretion system (T4SS). To better understand T4SS function, we analyzed the localization of its structural components and substrates by deconvolution fluorescence microscopy. GFP fusions to T4SS proteins with cytoplasmic tails, VirB8 and VirD4, or cytoplasmic T4SS substrate proteins, VirD2, VirE2, and VirF, localize in a helical pattern of fluorescent foci around the perimeter of the bacterial cell. All fusion proteins were expressed at native levels of
vir
induction. Importantly, most fusion proteins are functional and do not exhibit dominant-negative effects on DNA transfer to plant cells. Further, GFP-VirB8 complements a
virB8
deletion strain. We also detect native VirB8 localization as a helical array of foci by immunofluorescence microscopy. T4SS foci likely use an existing helical scaffold during their assembly. Indeed, the bacterial cytoskeletal component MinD colocalizes with GFP-VirB8. Helical arrays of foci are found at all times investigated between 12 and 48 h post
vir
induction at 19 °C. These data lead to a model with multiple T4SSs around the bacterial cell that likely facilitate host cell attachment and DNA transfer. In support, we find multiple T pili around
vir
-induced bacterial cells.
Age of Acquisition, Word Frequency, and Picture–Word Interference
Authors: Catling Jonathan C. , Dent Kevin , Johnston Robert A. , Balding Richard
Published: February 2010

In two experiments participants named pictures superimposed with unrelated words. The age of acquisition (AoA) of the picture names was manipulated. Additionally, the word frequency (WF, Experiment 1) or AoA (Experiment 2) of the interfering distractor words was manipulated. Early-acquired pictures were named faster than their late-acquired counterparts. Both WF and AoA modulated the degree of interference from the irrelevant word; low-frequency and late-acquired words produced most interference. In neither case did the WF or AoA of the distractor word interact with the AoA of the picture. The results show that in the context of word processing both WF and AoA have similar effects.
Deoxynivalenol Distribution in Flour and Bran of Spring Wheat Lines with Different Levels of Fusarium Head Blight Resistance
Authors: Nishio Zenta , Takata Kanenori , Ito Miwako , Tanio Masahiko , Tabiki Tadashi , Yamauchi Hiroaki , Ban Tomohiro
Published: February 2010

The level of the fungal toxin deoxynivalenol (DON) in milled flour and its partitioning between flour and bran of 15 spring wheat (Triticum aestivum) lines with different levels of Fusarium head blight (FHB; mainly caused by Fusarium graminearum) resistance was investigated in Hokkaido, Japan between 2004 and 2007. The DON levels in flour (DONf) and bran (DONb) showed positive linear relationships with DON levels in whole kernels (DONk) (R2 = 0.94, n = 60, P ≤ 0.01 and R2 = 0.93, n = 60, P ≤ 0.01, respectively). Results indicated that the DON partitioning ratio between flour and bran is primarily related to the level of DONk, and the DON level was approximately doubled in DONb and halved in DONf for any level of DONk. Only one pattern of DON partitioning supported the conventional strategy to select FHB-resistant lines.
Continuous Lighting Reduces Conidial Production and Germinability in the Rose Powdery Mildew Pathosystem
Authors: Suthaparan A. , Stensvand Arne , Torre S. , Herrero Maria L. , Pettersen R. I. , Gadoury David M. , Gislerød Hans Ragner
Published: February 2010

The effect of day length on production and germinability of conidia and severity of disease caused by Podosphaera pannosa, the causal agent of rose powdery mildew, was studied. Whole potted plants or detached leaves of Rosa interspecific hybrid ‘Mistral’ were inoculated with P. pannosa and exposed to 0, 12, 18, 20, 22, or 24 h of artificial light per day in growth chambers equipped with mercury lamps. Increasing duration of illumination from 18 to 20 to 24 h per day reduced production of conidia by 22 to 62%. Exposure to 24 h of illumination per day also strongly reduced disease severity compared with 18 h. Our results suggest that increasing day lengths from 18 h per day to 20 to 24 h may suppress the disease significantly and, thereby, reduce the need for fungicide applications against powdery mildew.
Multi-Year Evaluation of Commercial Soybean Cultivars for Resistance to Phytophthora sojae
Authors: Slaminko T. L. , Bowen C. R. , Hartman G. L.
Published: February 2010

Phytophthora sojae causes damping-off, root rot, and stem rot of soybean, particularly in poorly drained soils. Soybean cultivar resistance is one of the primary methods to control this disease, with Rps1c, Rps1k, and Rps1a being the most commonly used genes. The Varietal Information Program for Soybeans (VIPS) at the University of Illinois evaluates soybean cultivars for resistance to a number of diseases including Phytophthora root rot (PRR). The objectives of this research were to evaluate PRR resistance among commercial cultivars or advanced lines, and to compare these results with the information on PRR resistance provided by the company that entered the cultivar in VIPS. Each year from 2004 to 2008, between 600 and 900 cultivars were evaluated for resistance to either race 17 or 26 of P. sojae using the hypocotyl inoculation method. P. sojae single resistance genes were reported in 1,808 or 51% of the entries based on company information. Of these, the most commonly reported resistance genes were Rps1c (50%), Rps1k (40%), and Rps1a (10%). To a much smaller degree, companies reported using Rps3a (0.3%), Rps1b (0.2%), and Rps7 (0.2%). For the duration of the 5-year testing period, almost half of the cultivars (46%) were entered in VIPS with no reported resistance genes, and only nine out of a total of 3,533 entries (less than 0.3%) reported a stacked combination of resistance genes. Agreement between company-reported genes and any resistance found in the VIPS PRR evaluation was highest for those cultivars claiming to have Rps1c (90%) and Rps1k (83%), followed by Rps1a (70%). On average, 54% of the cultivars submitted to VIPS each year were new, reflecting the rapid development and turnover of soybean cultivars provided by the soybean seed companies.
First Report of Dollar Spot of Seashore Paspalum (Paspalum vaginatum) Caused by Sclerotinia homoeocarpa in South China
Authors: Lv C.-C. , Luo L.-X. , Li J.-Q. , Hsiang T.
Published: February 2010

Seashore paspalum (Paspalum vaginatum Swartz), a warm-season perennial grass, is native to tropical and subtropical regions of North and South America (1). Its fine texture and tolerance to low mowing and hypersaline environments make it a commercially promising turfgrass species for coastal regions of south China. In late March 2009, disease symptoms were observed from two golf course fairways in Shenzhen and Foshan, Guangdong Province, China. Small, round patches from 25 to 75 mm in diameter were found to be consisting of bleached, straw color leaf lesions bounded by reddish brown margins. Similar patches had previously been observed on seashore paspalum since 1997 in Guangdong Province, but this turf species has been grown in southern China only since the early 1990s. These symptoms were observed when daytime temperatures were above 25°C and with heavy dew formation at night. Greatest severity was seen in the spring and fall. Several contact and systemic fungicides were applied after first symptoms were observed and they were usually successful in suppressing disease. To confirm the disease as dollar spot, isolates from Shenzhen and Foshan were obtained by plating diseased leaf blades of P. vaginatum (cv. Salam) on potato dextrose agar media. Isolates produced white, fluffy, aerial mycelium, columnar when mature, and usually with a cinnamon base and dark brown or black substratal stroma on and in the agar. One representative isolate from each location was chosen for pathogenicity testing. Six-week-old P. vaginatum (cv. Salam) grown from seed in pots was inoculated, with 5-mm-diameter agar plugs with hyphae from 5-day-old cultures, by direct placement onto leaves and with three replicate pots per isolate. Plants treated with sterile agar plugs served as controls. Inoculated turf was incubated at 25°C with 12-h light/dark conditions. A plastic film was also placed over the pots to retain moisture. Chlorotic leaf lesions started to develop 4 days after inoculation and became a bleached straw color. The same fluffy, white fungus was reisolated from lesions, while no disease was observed on controls, thus completing Koch's postulates. The internal transcribed spacer (ITS) region of the ribosomal DNA was amplified from DNA extracted from two isolates using primers ITS5 and ITS4 (2), and the 610-bp sequences showed 98% similarity with Sclerotinia homoeocarpa F.T. Bennett in GenBank and have been deposited as Accessions GQ386985 and GU002301. Dollar spot on P. vaginatum has been commonly observed in the United States (1). To our knowledge, this is the first confirmed report of dollar spot on P. vaginatum in China or from any host plant in China.

References: (1) R. R. Duncan and R. N. Carrow. Seashore Paspalum: The Environmental Turfgrass. John Wiley and Sons, Toronto, ON, Canada. 2000. (2) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press Inc., New York, 1990.
First Report on the Susceptibility of Sweet Pepper Crops to Tomato chlorosis virus in Brazil
Authors: Barbosa J. C. , Teixeira L. D. D. , Rezende J. A. M.
Published: February 2010

In June of 2009, sweet pepper (Capsicum annuum cvs. Elisa and Prador) plants exhibiting interveinal chlorosis, some necrosis, and mild upward leaf curling on the intermediate leaves were found in three protected crops in the municipality of São Miguel Arcanjo, São Paulo state, Brazil. Incidence of symptomatic plants varied from 70 to 100%. Abundant whitefly adults were seen in all crops. Initially, total DNA was separately extracted from seven symptomatic plants and submitted to a PCR reaction using the universal primer pairs PAL1v1978/PAR1c496 and PBL1v2040/PCRc1 for begomovirus (3). The results were negative. The same samples were also analyzed for infection with Tomato infectious chlorosis virus (TICV) and Tomato chlorosis virus (ToCV) (genus Crinivirus, family Closteroviridae). Total RNA was extracted separately from leaves of each symptomatic plant and used for one-step reverse transcription (RT)-PCR using the HS-11/HS-12 primer pair, which amplifies a fragment of 587 bp from the highly conserved region of the heat shock protein (HSP-70) homolog gene reported for TICV and ToCV (1). The RT-PCR product was subsequently tested by nested-PCR for single detection of TICV and ToCV using primer pairs TIC-3/TIC-4 and ToC-5/ToC-6, respectively (1). Only one fragment of approximately 463 bp was amplified from the five plants with the primer pair specific for ToCV. No amplification was obtained with the primers specific for TICV. Four purified amplicons of 463 bp were directly sequenced in both directions. Sequence comparisons of the 419-bp consensus sequence, encompassing nucleotides 750 and 1,167 of the HSP-70 homolog gene, revealed 98% identity with the reported sequences of tomato infecting isolates of ToCV from Brazil (GenBank Accession No. EU868927) and the United States (GenBank Accession No. AY903448). Virus-free adults of Bemisia tabaci biotype B were confined on symptomatic pepper leaves for a 48-h acquisition access period. Twenty adults were transferred to one plant of sweet pepper cv. Magda for a 24-h inoculation access period. The sweet pepper plant exhibited the original symptoms on the leaves 67 days after inoculation under greenhouse conditions. Infection by ToCV was confirmed by RT-PCR. The susceptibility of sweet pepper plants to ToCV was previously reported in Spain (2), whereas in the United States, this species was experimentally found as nonhost for this virus (4). Further studies are needed to better understand the variable susceptibility of sweet pepper to ToCV.

References: (1) C. I. Dovas et al. Plant Dis. 86:1345, 2002. (2) G. Lozano et al. Plant Dis. 88:224, 2004. (3) M. R. Rojas et al. Plant Dis. 77:340, 1993. (4) W. M. Wintermantel et al. Plant Dis. 90:814, 2006.
First Report of the Huanglongbing Bacterium ‘Candidatus Liberibacter asiaticus’ Infecting Satkara (Citrus macroptera) in India
Authors: Das A. K. , Kumar A.
Published: February 2010

In India, satkara (Citrus macroptera) is found in the northeastern regions of Shella and Dowki near Cherrapunji in Meghalaya, the Jampui Hills of Tripura and Mizoram, and the Chendel District of Manipur. Locally, it is called satkara because ‘sat’ refers to multiples of seven and the fruit generally contains fourteen segments. The fruit is used in the preparation of pickles and its oil is used in the perfume industry. In January 2007, in Behliangchhip, Jampui Hills, Tripura, India, we noticed seven satkara trees of 26 showing leaf mottling and yellowing in young shoots, symptoms typical of huanglongbing (HLB). HLB is a destructive citrus disease caused by a nonculturable, phloem-limited alpha-proteobacterium of the genus ‘Candidatus Liberibacter’. Among the three known ‘Ca. Liberibacter’ species (Ca. Liberibacter asiaticus, Ca. L. africanus, and Ca. L. americanus), only Ca. L. asiaticus has been reported in India (1) but not from satkara. To identify the pathogen, total DNA was extracted and purified from 200 mg of leaf midribs from five symptomatic and five symptomless trees with the DNeasy Plant Mini Kit (Qiagen, Gmbh, Hilden, Germany) as per the manufacturer's instructions. Samples were tested for ‘Ca. L. asiaticus’ by PCR with primer sets OI1/OI2c targeting the 16S rDNA locus (3) and A2/J5 targeting the beta-operon locus of ribosomal proteins (2). DNA samples from all symptomatic leaves were positive with both primer sets. The OI1/OI2c primers generated an amplicon of approximately 1,160 bp and digestion of the amplicon by XbaI yielded two DNA fragments of approximately 640 bp and 520 bp, suggesting the presence of ‘Ca. L. asiaticus’(3). The A2/J5 primer set generated an ~703-bp amplicon, indicating ‘Ca. L. africanus’ was not present. No DNA was amplified from the asymptomatic satkara trees. One each of the OI1/OI2c and A2/J5 amplicons was purified, cloned (pGEM-T Easy vector, Promega, Hampshire, UK) and sequenced (Bangalore Genei, Bengaluru, Karnataka, India). The derived sequences, 1167 bp for the OI1/OI2c amplicon and 703 bp for the A2/J5 amplicon, have been deposited in the GenBank database under Accession Nos. GQ369792 and GU074017, respectively. Sequence comparison revealed that GQ369792 and GU074017 shared >99% identity to the corresponding regions of ‘Ca. L. asiaticus’ in the GenBank database. No DNA was amplified by PCR with primer set GB1/GB2 (4) specific for ‘Ca. L. americanus’. To our knowledge, this is the first report of molecular identification of ‘Ca. L. asiaticus’ infecting satkara in India.

References: (1) A. K. Das. Curr. Sci. 87:1183, 2004. (2) A. Hocquellet et al. Mol. Cell. Probes 13:373, 1999. (3) S. Jagoueix et al. Mol. Cell. Probes 10:43, 1996. (4) D. C. Teixeira et al. Mol. Cell. Probes 19:173, 2005.
First Report of Arceuthobium blumeri on Pinus ayacahuite and A. globosum subsp. globosum on P. durangensis from Sinaloa, Mexico
Authors: Quiñonez Barraza S. , Mathiasen R.
Published: February 2010

Arceuthobium blumeri A. Nelson (Blumer's dwarf mistletoe, Viscaceae) is a parasite of Pinus ayacahuite Ehrenberg ex Schlechtendahl (Mexican white pine) and P. strobiformis Engelm. (southwestern white pine) in the Sierra Madre Occidental of northern Mexico (3). It is widely distributed in Chihuahua and Durango and is known from one location in Sonora (3,4). A. globosum Hawksworth & Wiens subsp. globosum (rounded dwarf mistletoe) parasitizes several pine species in the same areas of Mexico, but extends as far south as northern Jalisco (3). In July 2005, S. Quiñonez Barraza observed both of these dwarf mistletoes in Ejido San José del Barranco, Municipio de Badiraguato, Sinaloa, Mexico. A. blumeri was observed parasitizing P. ayacahuite at two locations: Paraje Faldeo Rancho del Oso (25°39′18″N, 107°01′27″W, elevation 2,600 m) and Paraje La Tableta (25°40′14″N, 107°01′33″W, elevation 2,520 m). The host at these two locations was identified by cone and needle morphology (1). Because the mistletoe plants were gray to straw in color and larger than 6 cm, they were clearly A. blumeri and not A. apachecum Hawksworth & Wiens, another dwarf mistletoe that parasitizes P. strobiformis in Arizona, New Mexico, and Coahuila, Mexico (3). A. globosum subsp. globosum was observed parasitizing P. durangensis Martínez at Paraje Puerto del Alacrán (25°39′52″N, 107°00′57″W, elevation 2,650 m). Infection of the pine hosts was severe at all three locations in Sinaloa and many trees were rated as class 5 and 6 by the 6-class dwarf mistletoe rating system (2). Large witches' brooms were formed on P. ayacahuite infected with A. blumeri, but no witches' brooms were formed on infected P. durangensis. Typically, A. globosum does not induce witches' brooms on infected pines (3). Specimens of A. blumeri and A. globosum subsp. globosum were collected and deposited at the Herbario CIIDIR, Instituto Politecnico Nacional, Durango, Dgo., 34220 Mexico. To our knowledge, this is the first report of A. blumeri and A. globosum subsp. globosum from Sinaloa, Mexico.

References: (1) A. Farjon and B. T. Styles. Flora Neotrop. Monogr. 75. 1997. (2) F. G. Hawksworth. USDA For. Serv. Gen. Tech. Rep. RM-78, 1977. (3) F. G. Hawksworth and D. Wiens. USDA For. Serv. Agric. Handb. 709, 1996. (4) R. Mathiasen et al. Madroño 55:161, 2008.
First Report of Root Rot Caused by Phytophthora sansomeana on Soybean in China
Authors: Tang Q. H. , Gao F. , Li G. Y. , Wang H. , Zheng X. B. , Wang Y. C.
Published: February 2010

Phytophthora sansomeana E.M. Hansen & Reeser is a newly described species and infects Douglas-fir, alfalfa, and soybean (1). Soybean production is an important part of the local economy in Yili State in Xinjiang Uygur Autonomous Region, northwest China. Unfortunately since 2005, root and stem rot disease has emerged on a number of farms. To identify the causal agent, plant samples with symptoms, including whole plant wilting or yellowing and stunting, were collected from fields during 2005 and 2008. Tissue from the edges of stem lesions was placed on selective lima bean agar (LBA) at 20°C for 3 to 4 days (2,3). Four single zoospore isolates of Phytophthora were obtained and maintained on LBA or 10% V8 juice liquid medium for examination of morphological and physiological characteristics. The colonies on LBA were aerial and rosaceous. The isolates were homothallic, and oogonia and oospores were readily produced in culture after 7 days on LBA plates. Oogonia averaged 38 μm and oospore width ranged from 23 to 48 μm and averaged 31 μm. Antheridia were approximately 15 × 12 μm and predominantly amphigynous in V8 juice. Sporangia were terminal or paragynous on persistent sporangiophores, nonpapillate, ovoid to obpyriform, and measured 52 × 35 μm with an average length/breadth ratio of 1.5. Hyphal swellings were produced in V8 juice 2 days after inoculation. The optimum temperature for growth was approximately 25°C and none occurred at 0 or 35°C. The internal transcribed spacer (ITS) sequence of this Phytophthora species (GenBank FJ966880) agreed 100% with sequences of P. sansomeana isolates deposited in GenBank (GQ853880 and EU925375). Pathogenicity tests were performed by hypocotyl inoculation method (2) using isolate Yili71 and potted soybean cv. Williams. Plants were grown in a growth chamber for 10 days before inoculation in 16-cm-diameter pots (2). Plants were inoculated with 2- × 2-mm plugs of mycelium grown for 4 days on LBA at 25°C, the plugs were adhered to the sides of wounded lower hypocotyls. As controls, plants were inoculated with LBA agar plugs without mycelium (2). Inoculated plants were maintained in a growth chamber at approximately 25°C with a 10-h dark/14-h light cycle and 50% relative humidity and symptom development was monitored daily for 1 week. Wounded stems inoculated with mycelium developed water-soaked lesions, which were similar to those seen on naturally infected plants. A Phytophthora sp. was reisolated from the margins of expanding lesions on wounded stems. To our knowledge, this is the first report of P. sansomeana infection of soybean in China and the threat it may pose to soybean production is unclear.

References: (1) E. M. Hansen et al. Mycologia 101:129. 2009. (2) Z. Y. Wang et al. Fungal Genet. Biol. 43:826, 2006. (3) X. B. Zheng. Methods in Phytophthora. Chinese Agriculture Press. Beijing, China, 1995.
First Report of Verticillium Wilt of Pistachio Caused by Verticillium dahliae in Spain
Authors: Moral J. , López-Escudero F. J. , Roca L. F. , Blanco-López M. A. , Trapero A.
Published: February 2010

Pistachio (Pistacia vera L.) trees in the Castilla La Mancha and Andalusia regions of central and southern Spain are grown close to olive orchards, which are often severely affected by Verticillium dahliae. During the last decade, wilt and death of one or several branches have been observed on pistachio (cv. Kerman) scions grafted on rootstock (P. terebinthus). Discoloration of vascular tissue was occasionally observed. In five surveyed orchards, incidence of affected trees was less than 2%. Wood chips with the bark removed from symptomatic trees were washed in running tap water, surface disinfested in 0.5% sodium hypochlorite for 1 min, and placed onto potato dextrose agar plates incubated at 25°C in the dark. Isolates were identified as V. dahliae on the basis of the characteristics of microsclerotia, conidiophores, and conidia. V. dahliae isolate V117 from olive was used as reference (1). The fungus was also isolated from soil in pistachio orchards using wet sieving and a modified sodium polypectate agar medium (1). Inoculum density varied from 0 to 4.73 microsclerotia per gram of soil. P. terebinthus seedlings were inoculated with two isolates of V. dahliae from pistachio trees by injecting the stems with 50 μl of a conidial suspension (107 conidia per ml) (2). Wilt symptoms of varying severity developed in 12 and 15 seedlings of the 20 pistachio seedlings inoculated with each of two isolates. No symptoms developed on the control seedlings. The pathogen was recovered from stem tissues of inoculated plants. To our knowledge, this is the first report of Verticillium wilt of pistachio in Spain. This study demonstrates the susceptibility of certain rootstocks to V. dahliae and the importance of using resistant rootstocks, such as UCBI (2), in pistachio plantations established on soils infested by V. dahliae.

References: (1) F. J. López-Escudero and M. A. Blanco-López. Plant Dis. 91:1372, 2007. (2) D. P. Morgan et al. Plant Dis. 76:310, 1992.
PAMDB, A Multilocus Sequence Typing and Analysis Database and Website for Plant-Associated Microbes
Authors: Almeida Nalvo F. , Yan Shuangchun , Cai Rongman , Clarke Christopher R. , Morris Cindy E. , Schaad Norman W. , Schuenzel Erin L. , Lacy George H. , Sun Xiaoan , Jones Jeffrey B. , Castillo Jose A. , Bull Carolee T. , Leman Scotland , Guttman David S. , Setubal João C. , Vinatzer Boris A.
Published: February 2010

Although there are adequate DNA sequence differences among plant-associated and plant-pathogenic bacteria to facilitate molecular approaches for their identification, identification at a taxonomic level that is predictive of their phenotype is a challenge. The problem is the absence of a taxonomy that describes genetic variation at a biologically relevant resolution and of a database containing reference strains for comparison. Moreover, molecular evolution, population genetics, ecology, and epidemiology of many plant-pathogenic and plant-associated bacteria are still poorly understood. To address these challenges, a database with web interface was specifically designed for plant-associated and plant-pathogenic microorganisms. The Plant-Associated Microbes Database (PAMDB) comprises, thus far, data from multilocus sequence typing and analysis (MLST/MLSA) studies of Acidovorax citrulli, Pseudomonas syringae, Ralstonia solanacearum, and Xanthomonas spp. Using data deposited in PAMDB, a robust phylogeny of Xanthomonas axonopodis and related bacteria has been inferred, and the diversity existing in the Xanthomonas genus and in described Xanthomonas spp. has been compared with the diversity in P. syringae and R. solanacearum. Moreover, we show how PAMDB makes it easy to distinguish between different pathogens that cause almost identical diseases. The scalable design of PAMDB will make it easy to add more plant pathogens in the future.
Initiation, Development, and Survival of Cleistothecia of Podosphaera aphanis and Their Role in the Epidemiology of Strawberry Powdery Mildew
Authors: Gadoury David M. , Asalf Belachew , Heidenreich M. Catherine , Herrero M. L. , Welser M. J. , Seem Robert C. , Tronsmo Anne Marte , Stensvand Arne
Published: February 2010

A collection of four clonal isolates of Podosphaera aphanis was heterothallic and was composed of two mutually exclusive mating types. Cleistothecial initials ≈20 to 30 μm in diameter were observed within 7 to 14 days after pairing of compatible isolates and developed into morphologically mature ascocarps within 4 weeks after initiation on both potted plants maintained in isolation and in field plantings in New York State and southern Norway. Ascospores progressed through a lengthy maturation process over winter, during which (i) the conspicuous epiplasm of the ascus was absorbed; (ii) the osmotic potential of the ascospore cytoplasm increased, resulting in bursting of prematurely freed spores in water; and, finally, (iii) resulting in the development of physiologically mature, germinable, and infectious ascospores. Release of overwintered ascospores from field collections was coincident with renewed plant growth in spring. Overwintered cleistothecia readily dehisced when wetted and released ascospores onto glass slides, detached strawberry leaves, and leaves of potted plants. Plant material exposed to discharged ascospores developed macroscopically visible mildew colonies within 7 to 10 days while noninoculated controls remained mildew free. Scanning electron and light microscopy revealed that cleistothecia of P. aphanis were enmeshed within a dense mat of hyphae on the persistent leaves of field-grown strawberry plants and were highly resistant to removal by rain while these leaves remained alive. In contrast, morphologically mature cleistothecia on leaves of nine deciduous perennial plant species were readily detached by simulated rain and seemed adapted for passive dispersal by rain to other substrates. Contrary to many previous reports, cleistothecia appear to be a functional source of primary inoculum for strawberry powdery mildew. Furthermore, they differ substantially from cleistothecia of powdery mildews of many deciduous perennial plants in their propensity to remain attached to the persistent leaves of their host during the intercrop period.
H-Gene-Mediated Resistance to Hessian Fly Exhibits Features of Penetration Resistance to Fungi
Authors: Harris M. O. , Freeman T. P. , Moore J. A. , Anderson K. G. , Payne S. A. , Anderson K. M. , Rohfritsch O.
Published: February 2010

Features shared by host-specific phytophagous insects and biotrophic plant pathogens include gene-for-gene interactions and the ability to induce susceptibility in plants. The Hessian fly shows both. To protect against Hessian fly, grasses have H genes. Avirulent larvae die on H-gene-containing resistant plants but the cause of death is not known. Imaging techniques were used to examine epidermal cells at larval attack sites, comparing four resistant wheat genotypes (H6, H9, H13, and H26) to a susceptible genotype. Present in both resistant and susceptible plants attacked by larvae were small holes in the tangential cell wall, with the size of the holes (0.1 μm in diameter) matching that of the larval mandible. Absent from attacked resistant plants were signs of induced susceptibility, including nutritive tissue and ruptured cell walls. Present in attacked resistant plants were signs of induced resistance, including cell death and fortification of the cell wall. Both presumably limit larval access to food, because the larva feeds on the leaf surface by sucking up liquids released from ruptured cells. Resistance was associated with several subcellular responses, including elaboration of the endoplasmic reticulum–Golgi complex and associated vesicles. Similar responses are observed in plant resistance to fungi, suggesting that “vesicle-associated penetration resistance” also functions against insects.
New algorithm (KAWAKAMI algorithm) to diagnose primary cutaneous vasculitis
Authors: KAWAKAMI Tamihiro
Published: February 2010

Palpable purpura tends to indicate involvement of small vessel vasculitis in the upper dermis. Livedo racemosa, nodular lesion and skin ulceration are indicative of involvement of small to medium‐sized vessel vasculitis in the lower dermis to subcutaneous fat. We set out to establish a new algorithm (KAWAKAMI algorithm) for primary cutaneous vasculitis based on the Chapel Hill Consensus Conference classification and our research results, and apply to the diagnosis. The first step is to measure serum antineutrophil cytoplasmic antibodies (ANCA) levels. If myeloperoxidase‐ANCA is positive, Churg–Strauss syndrome or microscopic polyangiitis can be suspected, and if the patient is positive for proteinase 3‐ANCA, Wegener’s granulomatosis is most likely. Next, if cryoglobulin is positive, cryoglobulinemic vasculitis should be suspected. Third, if direct immunofluorescence of the skin biopsy specimen reveals immunoglobulin A deposition within the affected vessels, Henoch–Schönlein purpura is indicated. Finally, the presence of anti‐phosphatidylserine–prothrombin complex antibodies and/or lupus anticoagulant and histopathological necrotizing vasculitis in the upper to middle dermis (leukocytoclastic vasculitis) indicates cutaneous leukocytoclastic angiitis, whereas if necrotizing vasculitis exists in the lower dermis and/or is associated with the subcutaneous fat, cutaneous polyarteritis nodosa is indicated. The KAWAKAMI algorithm may allow us to refine our earlier diagnostic strategies and allow for efficacious treatment of primary cutaneous vasculitis. In cutaneous polyarteritis nodosa, warfarin or clopidogrel therapies should be administrated, and in cases that have associated active inflammatory lesions, corticosteroids or mizoribine (mycophenolate mofetil) therapy should be added. We further propose prophylactic treatment of renal complications in patients with Henoch–Schönlein purpura.
Ciclopirox nail lacquer for the treatment of onychomycosis: An open non‐comparative study
Authors: SHEMER Avner , NATHANSOHN Nir , TRAU Henri , AMICHAI Boaz , GRUNWALD Marcelo H.
Published: February 2010

Onychomycosis is a relatively common disease accounting for up to 50% of all nail disorders. Topical treatment, although less effective than systemic, is usually preferred by patients. Topical antifungal nail lacquers have been formulated to provide better delivery of the antifungal agent to the nail unit. The purpose of this research is to evaluate the efficacy and safety of ciclopirox nail lacquer in the treatment of onychomycosis. Patients suffering from distal and lateral subungual toenail onychomycosis (DLSO) and lateral subungual onychomycosis (LSO) were treated by ciclopirox nail lacquer once daily for 9 months. Every week the nail lacquer was removed using acetone. Clinical nail status, KOH examination and mycological culture were recorded by the same investigator at 0, 3, 6 and 9 months. Thirty‐six patients completed the 9‐month regimen. Trichophyton rubrum was the most common pathogen. At the end of the study, good improvement to complete cure was observed in 13 patients (36%), 12 patients showed only mild to moderate improvement and 11 patients (31%) had no clinical improvement. No adverse effects were noted throughout the treatment period. Ciclopirox nail lacquer seems to be slightly more effective than other topical modalities and could be used in patients who cannot or do not want systemic treatment.