bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of resistance to thiabendazole in Helminthosporium solani (silver scurf) as a result of potato seed tuber treatment
Authors: HIDE G. A. , HALL S. M. 
Published: April 2007

Applying thiabendazole to potato seed tubers affected with silver scurf caused by Helminthosporium solani sensitive to thiabendazole decreased the severity of disease on progeny tubers at harvest, but about 50% of the isolates from these were resistant to the fungicide. The disease was not decreased when samples of the progeny tubers were treated with thiabendazole and planted in the following year, and the incidence of resistant isolates increased. Resistant isolates continued to be present when tubers were planted in the next 2 years without fungicide treatment. Treatment with a mixture of thiabendazole and imazalil also decreased the disease and fewer isolates were resistant than when treated with thiabendazole alone, although the proportion increased after treatment with the mixture in the following year. When seed tubers were infected with thiabendazole‐resistant H. solani, silver scurf on progeny tubers was not affected by thiabendazole applied to the seed tubers but was decreased by the mixture of thiabendazole and imazalil. Imazalil was equally effective against H. solani sensitive or resistant to thiabendazole.Some isolates of H. solani had grey aerial mycelium and of 516 of these isolates obtained in 4 years 29% were resistant to the fungicide. Other isolates produced small, black colonies and their frequency increased with thiabendazole treatment of seed tubers. Of 244 of these isolates, 62% were resistant.
The histology of processes associated with the infection of resistant and susceptible wheat cultivars with Septoria tritici
Authors: COHEN L. , EYAL Z. 
Published: April 2007

The development of Septoria tritici blotch on seedling leaves of the wheat cultivars Shafir (susceptible) and KVZ‐K4500 L.6.A.4 (resistant) was studied by light and fluorescence microscopy. Appressoria were usually located above a stomatal opening. Percentage germination, formation of appressoria and the pattern of invasion of the substomatal chamber were the same in the susceptible and resistant cultivars. Growth of hyphae was observed in the intercellular spaces of the leaf tissue of both cultivars.Autofluorescence was more commonly observed in the resistant accession, as was the affinity for trypan blue dye. Some lignification of cell walls and sparse deposition of callosic materials occurred in the resistant line. Leaves of KVZ‐K4500 L.6.A.4, which macroscopically appeared pycnidia‐free, revealed microscopically the presence of arrested, immature, pycnidia‐like aggregations that did not progress further under prolonged environmental conditions conducive for pycnidial induction.
The effects of white clover mosaic virus on vegetative growth and yield of clones of S.100 white clover
Authors: POTTER L. R. 
Published: April 2007

Ramet of eight clones of cultivar S.100 white clover were infected with white clover mosaic virus (WCMV) and compared with uninfected ramets. Infection reduced herbage yield over two cuts by between 25 and 75%, with a mean of 40% at both. Petiole length was reduced significantly by 8% at the first cut, but not at the second. There was an overall reduction of about 6% in mid‐rib length. The mean length of the longest stolon was reduced by about 20% at both cuts, but this did not reflect the reaction of whole plants as total stolon length was reduced by a mean of 43%, within a range of 25–75%. The mean dry weight of stolon was reduced by 47%, while stolon specific weight (weight per unit length) was reduced by 7%. The reduced leaf yield in WCMV‐infected plants was caused mainly by a reduction in stolon growth and not by a reduction in leaf size. Virus infection reduced the total number of growing points per plant by over 30%, but the number per metre of stolon was increased by over 20%. The total acid‐soluble carbohydrate content of stolons was unaffected.For all growth parameters measured, there was considerable variation between the eight clones in their reaction to WCMV infection, most clones being affected detrimentally. In one clone, however, leaf dry weight yield of infected plants at the first cut was double that of healthy plants. At the second cut, both leaf and total stolon dry weights were greater by 40%, the total number of growing points by 80%, and the growing points per metre of stolon by 30%.
Changes in morphology and measurement of cytokinin levels during the development of witches' brooms on cocoa
Authors: ORCHARD J. , COLLIN H. A. , HARDWICK K. , ISAAC SUSAN 
Published: April 2007

The anatomy of diseased stems from brooms induced on cocoa (Theobroma cacao) by the fungus Crinipellis perniciosa was examined using the scanning electron microscope, and the amounts of selected cytokinins were measured by immunoassay.Although the diseased stems were wider in diameter with a lower dry weight:fresh weight ratio than stems of healthy plants, the overall internal organization of tissues remained unchanged, and all the cell types were present. However, the vascular tissue was less differentiated in diseased stems since xylem vessels were absent and the ratio of phloem fibres and sieve tubes to phloem parenchyma was reduced. Cell sizes in diseased stems were larger for all tissues but cell numbers were unchanged except for xylem where fewer cells were seen.Cytokinins (zeatin, zeatin riboside, isopentenyl adenine and isopentenyl adenosine) were measured in healthy plants and diseased stems at specific stages of disease development. Of these cytokinins only zeatin riboside was present in significantly greater amounts in diseased tissue. The likely role of plant growth regulator balance in stem enlargement and proliferation in witches' broom disease of cocoa is discussed.
Records of foliage pathogens of Pinus species in tropical countries
Authors: IVORY M. H. 
Published: April 2007

Mycosphaerella gibsonii is reported from 19 countries on 24 Pinus spp., especially from seedlings and young plants, including first records for eight countries and five hosts. Mycosphaerella pini is also reported from 12 countries on 10 Pinus spp., especially from derelict research plots and abandoned plantations, including new records for Nepal, Philippines, Sri Lanka and Zambia. Records of M. gibsonii and M. pini from remote native blue pine forests and M. gibsonii from native Chir pine forests in Nepal suggest that both fungi are endemic to the Himalayan region as well as to Central America. Variation between ecotypes of these fungi from Asia and Africa suggests that both fungi are present in these regions as different ecotypes.Records of Sphaeropis sapinea confirm its widespread occurrence as a shoot blight pathogen and as a facultative pathogen in tropical countries; whereas the paucity of records for M. dearnessii and needle rusts (Coleosporium spp.) suggests that spread of these fungi is less readily achieved.
Effects of crop rotation and removal of crop debris on the soil population of two isolates of Verticillium dahliae
Authors: MOL L. , SCHOLTE K. , VOS J. 
Published: April 2007

Microsclerotia of Verticillium dahliae are produced in large numbers on senescing parts of host plants and remain viable in the soil for many years. Changes in the population density, i.e. density of microsclerotia, in the soil were measured in micro‐plots using two isolates of V. dahtiae, specific to either field bean or potato, several crop sequences comprising potato, field beans and barley, and either the removal of aerial debris of the crops or incorporation into soil.Potato was more susceptible to the potato isolate and field bean more susceptible to the field bean isolate. Removal of debris of potato and field bean reduced numbers of microsclerotia in the soil in the subsequent years, but removal of barley straw had no effect. Initially non‐infested control micro‐plots became infested, probably by the growth of potato roots into the naturally infested subsoil. The rate of increase of the microsclerotial population in the non‐infested control micro‐plots was larger than in the initially infested treatments, because more colonized debris was produced. It is concluded that removal of aerial debris of host crops is important to reduce the soil population of V. dahtiae.
Inhibition of polyamine biosynthesis in Phytophthora infestans and Pythium ultimum
Authors: WALTERS D. R. , KEENAN J. P. , COWLEY T. , McPHERSON A. , HAVIS N. D. 
Published: April 2007

Mycelial growth, polyamine concentrations and the activities of enzymes of polyamine biosynthesis and catabolism were examined in Phytophthora infestans and Pythium ultimum grown in the presence of difluoromethylornithine (DFMO), an inhibitor of omithine decarboxylase (ODC), and difluoro‐methylarginine (DFMA), an inhibitor of arginine decarboxylase (ADC). Growth of P. infestans was reduced by DFMO and a mixture of DFMO + DFMA, but was increased by DFMA at concentratiotis of 5 MM and greater, Polyamine concentrations and ODC activity were significantly reduced in P. infestans grown on all inhibitor treatments. In contrast, growth, polyamine concentrations and enzyme activities were not affected in P, ultimum exposed to the inhibitors.It seems unlikely that P. infestans and P. uttimum possess ADC activity, as neither of the products of ADC activity (agmatine and putrescine) could be detected in ADC assays. Although ODC from P. infestans was sensitive to DFMO, ODC from P. uttimum was insensitive to the inhibitor. Moreover, uptake of DFMO by P. infestans was three times greater than that observed by P. ultimum.
Genetics of specific resistance in pea (Pisum sativum) cultivars to seven races of Pseudomonas syringae pv. pisi
Authors: BEVAN J. R. , TAYLOR J. D. , CRUTE I. R. , HUNTER P J. , VIVIAN A. 
Published: April 2007

Seven races of Pseudomonas syringae pv. pisi were distinguished using eight differential cultivars of pea (Pisum sativum). Segregation among F2 populations of crosses between differential cultivars sequentially inoculated with races of P.s. pv. pisi provided evidence for four and possibly six putative resistance(R)/avirulence(A) gene pairs. R1, R2 and R3 are dominant resistance alleles at single loci, R4 is a dominant allele at a single locus which exhibits variable expression possibly dependent on genetic background. There is evidence that R3 and R4 are at linked loci. Homology tests provided proof of the occurrence of the alleles R2, R3 and R4 in more than one cultivar. Two other alleles, R5 and R6, were postulated to explain the observed segregation ratios in certain crosses.It can be inferred that P.s. pv. pisi races 2, 3 and 4 each carry a different single a virulence gene, race 6 carries no apparent avirulence genes, and race 7 carries at least A2, A3 and A4. Race 1 carries Al, A3, A4 and possibly A6; race 5 carries A2, A4 and possibly A5 and A6.
Heat treatment of plant propagation material for the control of fire blight
Authors: KECK M. , CHARTIER R , ZISLAVSKY W. , LECOMTE P. , PAULIN J. P. 
Published: April 2007

The thermal sensitivity of Erwinia amylovora was determined at 45° C and 50°C. In vitro assays with eight differetit strains showed that thermal death times did not exceed 70min at 45° C and 50min at 50° C (95% confidence interval). Heat treatments of naturally infected apple and pear shoots were performed using a moist and a dry heat procedure. When shoots were wrapped in wet cotton cloths (wet heat) and maintained in an incubator, no bacterial growth could be detected after an incubation of 5 h at 45° C. When shoots were sealed in polyethylene bags and immersed in water (dry heat), no Erwinia amytovora could be isolated after an immersion of 3 h at 45° C. Incubation at 50°C for 1 –2h in either condition did not eradicate the pathogen entirely. The failure rate of grafts using budwoods treated at the effective time‐temperature combinations did not exceed 25%.The present investigations showed that the use of thermotherapy techniques for controlling Erwinia amylovora in propagation material of apple and pear might be possible.
Charcoal rot (Macrophomina phaseolina) resistance and the effects of water stress on disease development in sorghum
Authors: DIOURTE M. , STARR J. L. , JEGER M. J. , STACK J. P. , ROSENOW D. T. 
Published: April 2007

In three field experiments, plants subjected to post‐flowering water stress and inoculated with Macrophomina phaseolina had greater development of charcoal rot symptoms than did inoculated plants not subjected to water stress. Two sorghum genotypes (B35‐6 and SC265‐14E) were found to be consistently more resistant to M. phaseolina, an assessment that was facilitated by the use of appropriate soil moisture conditions at the time of greatest plant susceptibility to charcoal rot.In addition, an isolate of M. phaseolina originally isolated from a sorghum genotype with resistance to charcoal rot caused greater symptom development than did two other isolates originally obtained from sorghum genotypes susceptible to charcoal rot.
Auxin, actin and growth of the Arabidopsis thaliana primary root
Authors: Rahman Abidur , Bannigan Alex , Sulaman Waheeda , Pechter Priit , Blancaflor Elison B. , Baskin Tobias I. 
Published: April 2007

SummaryTo understand how auxin regulates root growth, we quantified cell division and elemental elongation, and examined actin organization in the primary root of Arabidopsis thaliana. In treatments for 48 h that inhibited root elongation rate by 50%, we find that auxins and auxin‐transport inhibitors can be divided into two classes based on their effects on cell division, elongation and actin organization. Indole acetic acid (IAA), 1‐naphthalene acetic acid (NAA) and tri‐iodobenzoic acid (TIBA) inhibit root growth primarily through reducing the length of the growth zone rather than the maximal rate of elemental elongation and they do not reduce cell production rate. These three compounds have little effect on the extent of filamentous actin, as imaged in living cells or by chemical fixation and immuno‐cytochemistry, but tend to increase actin bundling. In contrast, 2,4‐dichlorophenoxy‐acetic acid (2,4‐D) and naphthylphthalamic acid (NPA) inhibit root growth primarily by reducing cell production rate. These compounds remove actin and slow down cytoplasmic streaming, but do not lead to mislocalization of the auxin‐efflux proteins, PIN1 or PIN2. The effects of 2,4‐D and NPA were mimicked by the actin inhibitor, latrunculin B. The effects of these compounds on actin were also elicited by a 2 h treatment at higher concentration but were not seen in two mutants, eir1‐1 and aux1‐7, with deficient auxin transport. Our results show that IAA regulates the size of the root elongation zone whereas 2,4‐D affects cell production and actin‐dependent processes; and, further, that elemental elongation and localization of PINs are appreciably independent of actin.
Cell division activity determines the magnitude of phosphate starvation responses in Arabidopsis
Authors: Lai Fan , Thacker Jennifer , Li Yuanyuan , Doerner Peter 
Published: April 2007

SummaryPhosphate (Pi) is a major limiting factor for plant growth. Plants respond to limiting Pi supplies by inducing a suite of adaptive responses comprising altered growth behaviour, enhanced Pi acquisition and reduced Pi demand that together define a distinct physiological state. In Pi‐starved plants, continued root growth is required for Pi acquisition from new sources, yet meristem activity consumes Pi. Therefore, we analysed the relationship between organ growth, phosphate starvation‐responsive (PSR) gene expression and Pi content in Arabidopsis thaliana under growth‐promoting or inhibitory conditions. Induction of PSR gene expression after transfer of plants to Pi‐depleted conditions quantitatively reflects prior levels of Pi acquisition, and hence is sensitive to the balance of Pi supply and demand. When plants are Pi‐starved, enhanced root or shoot growth exacerbates, whereas growth inhibition suppresses, Pi starvation responses, suggesting that the magnitude of organ growth activity specifies the level of Pi demand. Inhibition of cell‐cycle activity, but not of cell expansion or cell growth, reduces Pi starvation‐responsive gene expression. Thus, the level of cell‐cycle activity specifies the magnitude of Pi demand in Pi‐starved plants. We propose that cell‐cycle activity is the ultimate arbiter for Pi demand in growing organs, and that other factors that influence levels of PSR gene expression do so by affecting growth through modulation of meristem activity.
Differential regulation of closely related R2R3‐MYB transcription factors controls flavonol accumulation in different parts of the Arabidopsis thaliana seedling
Authors: Stracke Ralf , Ishihara Hirofumi , Huep Gunnar , Barsch Aiko , Mehrtens Frank , Niehaus Karsten , Weisshaar Bernd 
Published: April 2007

SummaryThe genes MYB11, MYB12 and MYB111 share significant structural similarity and form subgroup 7 of the Arabidopsis thaliana R2R3‐MYB gene family. To determine the regulatory potential of these three transcription factors, we used a combination of genetic, functional genomics and metabolite analysis approaches. MYB11, MYB12 and MYB111 show a high degree of functional similarity and display very similar target gene specificity for several genes of flavonoid biosynthesis, including CHALCONE SYNTHASE, CHALCONE ISOMERASE, FLAVANONE 3‐HYDROXYLASE and FLAVONOL SYNTHASE1. Seedlings of the triple mutant myb11 myb12 myb111, which genetically lack a complete subgroup of R2R3‐MYB genes, do not form flavonols while the accumulation of anthocyanins is not affected. In developing seedlings, MYB11, MYB12 and MYB111 act in an additive manner due to their differential spatial activity; MYB12 controls flavonol biosynthesis mainly in the root, while MYB111 controls flavonol biosynthesis primarily in cotyledons. We identified and confirmed additional target genes of the R2R3‐MYB subgroup 7 factors, including the UDP‐glycosyltransferases UGT91A1 and UGT84A1, and we demonstrate that the accumulation of distinct and structurally identified flavonol glycosides in seedlings correlates with the expression domains of the different R2R3‐MYB factors. Therefore, we refer to these genes as PFG1–3 for ‘PRODUCTION OF FLAVONOL GLYCOSIDES’.
WRINKLED1 specifies the regulatory action of LEAFY COTYLEDON2 towards fatty acid metabolism during seed maturation in Arabidopsis
Authors: Baud Sébastien , Mendoza Monica Santos , To Alexandra , Harscoët Erwana , Lepiniec Loïc , Dubreucq Bertrand 
Published: April 2007

SummaryThe WRINKLED1 (WRI1) transcription factor has been shown to play a role of the utmost importance during oil accumulation in maturing seeds of Arabidopsis thaliana. However, little is known about the regulatory processes involved. In this paper, comprehensive functional analyses of three new mutants corresponding to null alleles of wri1 confirm that the induction of WRI1 is a prerequisite for fatty acid synthesis and is important for normal embryo development. The strong expression of WRI1 specifically detected at the onset of the maturation phase in oil‐accumulating tissues of A. thaliana seeds is fully consistent with this function. Complementation experiments carried out with various seed‐specific promoters emphasized the importance of a tight regulation of WRI1 expression for proper oil accumulation, raising the question of the factors controlling WRI1 transcription. Interestingly, molecular and genetic analyses using an inducible system demonstrated that WRI1 is a target of LEAFY COTYLEDON2 and is necessary for the regulatory action of LEC2 towards fatty acid metabolism. In addition to this, quantitative RT‐PCR experiments suggested that several genes encoding enzymes of late glycolysis, the fatty acid synthesis pathway, and the biotin and lipoic acid biosynthetic pathways are targets of WRI1. Taken together, these results indicate new relationships in the regulatory model for the control of oil synthesis in maturing A. thaliana seeds. In addition, they exemplify how metabolic and developmental processes affecting the developing embryo can be coordinated at the molecular level.
Prevalence and correlates of burden among caregivers of patients with bipolar disorder enrolled in the Systematic Treatment Enhancement Program for Bipolar Disorder
Authors: Perlick Deborah A , Rosenheck Robert A , Miklowitz David J , Chessick Cheryl , Wolff Nancy , Kaczynski Richard , Ostacher Michael , Patel Jayendra , Desai Rani ,   the STEP‐BD Family Experience Collaborative Study Group
Published: April 2007

Objectives: Caring for a relative with schizophrenia or dementia is associated with reports of high caregiver burden, symptoms of depression, poor physical health, negligence of the caregiver's own health needs, elevated health service use, low use of social supports, and financial strain. This study presents the design and preliminary data on the costs and consequences of caring for a relative or friend with bipolar disorder from the Family Experience Study, a longitudinal study of the primary caregivers to 500 patients enrolled in the Systematic Treatment Enhancement Program for Bipolar Disorder.Methods: Subjects were primary caregivers of 500 patients with bipolar disorder diagnosed by the Mini International Neuropsychiatric Interview and the Affective Disorder Evaluation. Caregivers were evaluated within 1 month after patients entered Systematic Treatment Enhancement Program using measures of burden, coping, health/mental health, and use of resources and costs.Results: Eighty‐nine percent, 52%, and 61% of caregivers, respectively, experienced moderate or higher burden in relation to patient problem behaviors, role dysfunction, or disruption of household routine. High burden caregivers reported more physical health problems, depressive symptoms, health risk behavior and health service use, and less social support than less burden caregivers. They also provided more financial support to their bipolar relative.Conclusions: Burdens experienced by family caregivers of people with bipolar disorder are associated with problems in health, mental health, and cost. Psychosocial interventions targeting the strains of caregiving for a patient with bipolar disorder are needed.