bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the Immune Response of Striped Bass and Hybrid Bass
Authors: Noga Edward J. , Avtalion Ramy R. , Levy Michael
Published: December 2021

We developed methods for examining the pathophysical response of striped bass and hybrid bass to various forms of stress. This involved development of techniques for the measurement of lysozyme, mitogen blastogenesis, mixed lymphocyte reaction, and oxidative burst, which are important general indicators of systemic immune function. We also examined local immune defenses (epithelial integrity), as well as homeostatic indicators in blood, including osmotic balance and glucose. Acute stress resulted in significant perturbations in a number of parameters, including glucose, electrolytes, osmolarity, lysozyme, and mixed lymphocyte reaction. Most significantly, acute confinement stress resulted in severe damage to the epidermal epithelium, as indicated by the rapid (within 2 hr) development of erosions and ulcerations on various fins. There were significant differences in the resting levels of some immune functions between striped bass and hybrid bass, including response to mitogens in the leukocyte blastogenesis test. Our studies also revealed that there were significant differences in how striped bass and hybrid bass respond to stress, with striped bass being much more severely affected by stress than the hybrid. This was reflected in more severe changes in glucose, cortisol dynamics, and plasma lysozyme. Most significantly, striped bass developed more severe idiopathic skin ulceration after stress, which may be a major reason why this fish is so prone to develop opportunistic bacterial and fungal infections after stress. Hybrid bass injected with equine serum albumin developed a typical humoral immune response, with peak antibody production 28 days after primary immunization. Fish that were exposed to a chronic stress after a primary immunization showed almost complete inhibition of antibody production.
Induction of Resistance to Postharvest Diseases and Extension of Shelf-Life of Fruits and Vegetables by Ultra-Violet Light
Authors: Chalutz Edo , Wilson Charles , Droby Samir , Gaba Victor , Stevens Clauzell , Fluhr Robert , Lu Y.
Published: December 2021

Following preliminary observations by one of the collaborating scientists on this project and the completion of a 1-year, BARD-supported feasibility study (IS-1908-90F), this 3-year BARD project has been executed. The main objectives of the research were to elucidate biochemical and pathological aspects of UV-induced resistance in fruits and vegetables, to characterize physical and biological variables of induced resistance and delay of ripening, and to explore the application of the treatment as a control practice of postharvest diseases and shelf-life extension of fruits and vegetables. Our findings, which are detailed in numerous joint publications, have shown that the effect of UV-C light on induction of resistance and delay of ripening is a general one and of wide oddurrence. Apart from surface sterilization of the commodity, the reduction of decay of different fungi has been associated with and induced resistance phenomenon which gradually builds up within 24 to 48 hours after the UV treatment and can be reversed by visible light. In citrus, induced resistance has been associated with increased activity of the enzymes phenylalanine ammonia-lyase and peroxidase, and with the levels of endglucanase and chitinase. In tomato, resistance was correlated with the production of high levels of tomatine. Our study of some molecular aspects of the induced resistance in grapefruit has revealed the induction of a cDNA which represents a gene encoding for an isoflavone reductase-like protein that, in legumes, has been associated with phytoalexin biosynthesis. This gene was cloned and sequenced. Delay of ripening was associated in tomato with inhibition of ethylene production, carotenoid synthesis, and chlorophyll degradation and with the presence of high levels of polyamines. In peach fruit epiphytic populations of a yeast increased following the UV treatment. Pilot-size treatment and packing lines were constructed in the US and Israel to test the application of the UV treatment on a semi-commercial scale. Although effective in reduction of decay and delay of ripening, a number of problems will have to be addressed before practical application of this methodology can be realized. The main issues are associated with the temporal and variable response to the treatment, and its relationship to the maturity and date of harvest of the commodity.
Influence of Ruminal Starch Degradability on Performance of High Producing Dairy Cows
Authors: Huber John Tal , Miron Joshuah , Theurer Brent , Bruckental Israel , Swingle Spencer
Published: December 2021

This research project entitled "Influence of Ruminal Starch Degradability on Performance of High Producing Dairy Cows" had the following objectives: a) Determine effects of feeding varying amounts of ruminally degradable starch (RDS) on efficiency of milk and milk protein production; and 2) Investigate digestive and metabolic mechanisms relating to lactation responses to diets varying in ruminal and total starch degradability. Four lactation studies with high producing cows were conducted in which steam-flaked (~ 75% RDS) was compared with dry-rolled sorghum (~ 50% RDS) grain. All studies demonstrated increased efficiency of conversion of feed to milk (FCM/DMI) and milk protein as amount of RDS in the diet increased by feeding steam-flaked sorghum. As RDS in diets increased, either by increased steam-flaked sorghum, grinding of sorghum, or increasing the proportion of wheat to sorghum, so also did ruminal and total tract digestibilities of starch and neutral-detergent soluble (NDS) carbohydrate. Despite other research by these two groups of workers showing increased non-ammonia N (NAN) flowing from the rumen to the duodenum with higher RDS, only one of the present studies showed such an effect. Post-absorptive studies showed that higher dietary RDS resulted in greater urea recycling, more propionate absorption, a tendency for greater output of glucose by the liver, and increased uptake of alpha-amino nitrogen by the mammary gland. These studies have shown that processing sorghum grain through steam-flaking increases RDS and results in greater yields and efficiency of production of milk and milk protein in high producing dairy cows.
Hormonal and Nutritional Stretegies to Optimize Reproductive Function and Improve Fertility of Dairy Cattle during Heat Stress in Summer
Authors: Wolfenson David , Thatcher William W. , Meidan Rina , Staples Charles R. , Flamenbaum Israel
Published: December 2021

The BARD program includes two main parts. In the first, experiments were conducted to complete our understanding of the mechanisms responsible for the impairment of reproductive functions under heat stress. Experiments focused on follicular development and function, since results obtained in our previous BARD project indicate that the preovulatory follicle is susceptible to heat stress. The theca cells, sensitive to thermal stress, produced less androgen during the summer, as well as during the autumn. Similarly, luteinized theca cells obtained from cows in summer produced much less progesterone than in winter. Granulosa cells and luteinized granulosa cells were less susceptible to heat stress. A delayed effect of heat stress on follicular development, on suppression of dominance and on steroid production by theca and granulosa cells was noted. This may be related to the low fertility of cows during the cool months of autumn. In the second part, experiments were conducted aiming to improve fertility in summer. The timed AI program was developed using two injections of GnRH coupled with PGF2a. It was found effective in improving reproductive performance in lactating cows. Limitations induced by heat stress on estrus detection were eliminated with the timed AI management program. Replacing the second injection of GnRH with hCG instead of GnRH agonist increased plasma progesterone levels post ovulation but did not improve fertility. Use of the timed AI program in summer, shortened days open and increased the net revenue per cow, however, it did not protect the embryo fiom temperature-induced embryonic mortality. Incorporation of a GnRH-agonist implant into the timed AJ program was examined. The implant increased plasma progesterone and LH concentrations and altered follicular dynamics. The use of a GnRH-implant enhanced pregnancy rate in cows with low body conditions. In a timed embryo transfer experiment, the use of fresh or frozen in vitro produced embryos was compared in the summer to improve fertility. The use of flesh embryos (but not frozen ones) improved pregnancy rate, however, substantial embryonic death occurred between 21 and 45 days. The timed AI program, which is now being used commercially, shortened days open, and increased pregnancy rate during summer. Other approaches which were found to improve fertility in small-scale studies, need to be tested again in large-scale field trials.
Expression and Inheritance of Growth Hormone Gene Constructs and Selective Breeding of Transgenic Farmed Fish
Authors: Dunham Rex A. , Moav Boaz , Chen Thomas , Cavari Benzion
Published: December 2021

Objectives: To accomplish stable expression, inheritance of transgenes and growth improvement in transgenic channel catfish, Ictalurus punctatus, and common carp, Cyprinus carpio, containing growth hormone (GH) genes, develop transgenic fish with all fish constructs, determine the relationships between copy number, expression and growth, determine the combined affect of selective breeding and gene transfer and assess environmental risk of transgenic fish. To develop mechanisms of triploidization for transgenic carp. Results: Performance of transgenic channel catfish was made uniform by selection. Growth of channel catfish and common carp was improved 40-50% more by combining gene transfer of GH genes with selection and crossbreeding than with either selection of crossbreeding. Growth improvement of transgenic catfish was not strongly correlated with copy number and expression levels. Progress was made in producting triploid transgenic common carp. Insertion of salmonid GH gene did not alter reproductive performance in channel catfish. Transgenic channel catfish grew no faster than controls when they had to forage on natural food and transgenic individuals were slightly more vulnerable to predation indicating that fitness of transgenic individuals in natural conditions is less than or equal to non-transgenic channel catfish. Contribution to Agriculture: These experiments are the first to demonstrate that transgenic fish can increase aquaculture production in the aquaculture production in the aquaculture environment. This research also demonstrated that maximum benefit of gene transfer in farmed fish is attained when combined with traditional selective breeding.
Prediction of Immunocompetence and Resistance to Disease by Using Molecular Markers of the Major Histocompatibility Complex
Authors: Lamont Susan J. , Heller E. Dan , Cahaner Avigdor
Published: December 2021

This project utilized two live-animal populations in an integrated research program to identify molecular markers for immune response and disease resistance. The populations each had their foundation from meat-type commercial breeder chicken lines of their respective countries. Investigations effectively used unique availability of resources in each country to study commercial-type environments in Israel and line-crosses with diverse inbred lines in the US. Two bacterial systems were investigated to cover both respiratory and gastrointestinal, and primary and secondary, infections. Individual experimental groups of animals were evaluated for combinations of vaccine antibody levels, response to pathogen challenge, growth parameters, genetic background and molecular markers. The positive association of antibody level with resistance to disease was confirmed. Effectiveness of genetic selection for vaccine antibody response level was demonstrated. Molecular markers, both inside and outside the MHC region, were associated with antibody response and resistance to disease. Markers were shown to have a generalized effect, by association with multiple traits of immune response and disease resistance. The impact of genetic background on marker effect was shown to be important. The overall results demonstrate the effectiveness of selection on vaccine antibody response and the potential of molecular marker-assisted selection to improve efficiency of production of meat-type chickens by reducing genetic susceptibility to disease.
Significance of Oxytocin and Oxytocin Receptors in Bovine Pregnancy
Authors: Fields Michael J. , Shemesh Mordechai , Fuchs Anna-Riitta
Published: December 2021

Oxytocin has multiple actions in bovine reproductive tract and it was our purpose to determine the nature of these actions and their significance for the physiology of bovine reproduction. The bovine oxytocin receptors (OTR) gene was cloned and its expression studied during the cycle and pregnancy. OTR mRNA changed in parallel with OTR with control occurring mainly at the transcriptional level. However, the endocrine regulation of OTR were found in endometrium and cervical mucosa at estrus and at parturition. In both tissues OTR were suppressed in the luteal phase and early pregnancy. Whereas cervical OTR remained suppressed throughout pregnancy, endometrial OTR began to increase soon after implantation and reached higher concentrations in midpregnancy than at estrus. OTR in caruncles did not increase until third trimester, and OTR in cervical mucosa, cotyledons and fetal membranes increased only at term. Myometrial OTR showed less variation and OTR were present throughout the cycle and pregnancy but increased significantly during mid- and late pregnancy. OTR were localized in endometrial epithelial cells and lumina epithelial cells of cervical mucosa as determined by immunohistochemistry. Endometrial OTR were functional throughout pregnancy and mediated PGF release from day 50 onwards in a receptor density related manner. OTR in cervical mucosa mediated PGE release both in vivo and in vitro, as shown in cyclic cows. The ontogeny of uterine OTR was studied from third trimester fetal stage until puberty. OTR were present in endometrium and cervical mucosa in high concentrations throughout this period; myometrial OTR began to increase somewhat later but also reached adult values by 6-mo of age. In the prepuberal heifers OT injections failed to initiate PGF2a, release. The influence of steroids on the effect of OT was examined. Ovariectomy and E2 were without effect, but P4 with or without E2 induced a massive PGF2a release in response to OT in spite of reduced OTR. Bovine cyclooxygenases (COX-1 and COX-2) were cloned and their expression studied in the endometrium of prepuberal heifers and pregnant cows. Untreated and E2 treated prepuberal heifers did not express COX-2 but P4 treated heifers did express the mRNA for COX-2, albeit weakly. During the second half of pregnancy COX-2 mRNA was strongly expressed in cotyledons and somewhat less in caruncles, whereas endometrium, myometrium and cervical mucosa showed only weak, if any, COX-2 mRNA under basal conditions. However, 2 h after OT injection significant increases in COX-2 mRNA were found in endometrial RNA. Thus OT is capable of inducing the expression of the inducible COX-2 gene, and hence the conversion of arachidonic acid to prostanoids. The results indicate that the functions of OT are numerous and probably essential for successful pregnancy and parturition.
Molecular Analysis by SSR of Genes Associated with Alkaloid Synthesis in a Segregating Monoploid Potato Family
Authors: Veilleux Richard E. , Hillel Jossi , Miller A. Raymond , Levy David
Published: December 2021

More than 15,000 anthers of an interspecific hybrid (CP2) between two diploid (2n=2x=24) potato species, Solanum chacoense (weedy) and S. phureja (cultivated), were cultured to generate a family of monoploid (haploid, 2n-1x=12) plants. Of 260 regenerated plants, 34 were monoploid, 210 diploid and 16 tetraploid. SSR analysis revealed that six monoploids were genetically identical and 14 diploids were homozygous, thus limiting the population to 42 (28 monoploids and 14 homozygous diploids). New microsatellite loci were developed for potato from database sequences (15), a conventional genomic library (6), an enriched library (18) and tomato (11). Of these, 13 were polymorphic in the CP2 family and 11 were used to study genetic segregatin. Four of 11 exhibited skewed segregation in the monoploid family. Seven of 18 microsatellite markers were polymorphic and informative on a set of 12 tetraploid potato cultivars. Acetylleptinidine (ALD) is the aglycone of leptines, a natural defense against insects, especially the highly destructuve Colorado potato beetle. ALD is absend in S. phureja but highly expressed in the S. chacoense parent of CP2. A backcross population between CP2 and tis S. phureja parent was used to examine segregation for ALD. Bulks of 10 backcross individuals that expressed ALD and 10 that did not were used to identify putative RAPD markers associatd with the trait. Of 80 primers tested, one putative marker amplified by OPQ02 was present in eight of ten individuals comprising the high bulk and absent in all 10 individuals comprising the low bulk. This is a putative marker for ALD expression in potato.
Mapping Quantitative Trait Loci in the Woody Perennial Plant Genus Citrus
Authors: Moore Gloria A. , Ben-Hayyim Gozal , Guy Charles L. , Holland Doron
Published: December 2021

As is true for all crops, production of Citrus fruit is limited by traits whose characteristics are the products of many genes (i.e. cold hardiness). In order to modify these traits by marker aided selection or molecular genetic techniques, it is first necessary to map the relevant genes. Mapping of quantitative trait loci (QTLs) in perennial plants has been extremely difficult, requiring large numbers of mature plants. Production of suitable mapping populations has been inhibited by aspects of reproductive biology (e.g. incompatibility, apomixis) and delayed by juvenility. New approaches promise to overcome some of these obstacles. The overall objective of this project was to determine whether QTLs for environmental stress tolerance could be effectively mapped in the perennial crop Citrus, using an extensive linkage map consisting of various types of molecular markers. Specific objectives were to: 1) Produce a highly saturated genetic linkage map of Citrus by continuing to place molecular markers of several types on the map. 2) Exploiting recently developed technology and already characterized parental types, determine whether QTLs governing cold acclimation can be mapped using very young seedling populations. 3) Determine whether the same strategy can be transferred to a different situation by mapping QTLs influencing Na+ and C1- exclusion (likely components of salinity tolerance) in the already characterized cross and in new alternative crosses. 4) Construct a YAC library of the citrus genome for future mapping and cloning.
Influence of Small Intestinal Protein on Carbohydrate Assimilation in Beef and Dairy Cattle
Authors: Harmon David L. , Bruckental Israel , Huntington Gerald B. , Aharoni Yoav , Arieli Amichai
Published: December 2021

The long term goal of the proposed research, "Influence of small intestinal protein on carbohydrate assimilation and metabolism in beef and dairy cattle" was to define the limits of small intestinal starch digestion and clarify regulatory mechanisms involved in starch assimilation in cattle. It was hypothesized that dietary protein plays a critical role in the regulation of intestinal digestion; however, studies clearly identifying this role were lacking. The first two experiments quantified starch digestion (disappearance from the small intestine) in response to known increments in duodenal protein supply and found that the quantity of DM, OM and starch disappearing from the small intestine increased linearly (P <.01) with protein infusion. A follow-up experiment also demonstrated that casein infusion linearly increased pancreatic a-amylase concentration and secretion rate. The final experiment provided critical data on metabolic fates of glucose derived from intestinal starch digestion. These data demonstrated that increasing postruminal starch supply does increase the metabolism of glucose by visceral tissues: however, this increase is minor (20%) compared with the increase in portal production (70%). These changes can have a dramatic impact on the glucose economy of the animal and result in large increases in the amount of glucose reaching peripheral tissues.
Regulation by Light of Plant Potassium Uptake through K Channels: Biochemical, Physiological and Biophysical Study
Authors: Moran Nava , Crain Richard , Reiter Wolf-Dieter
Published: December 2021

The swelling of plant motor cells is regulated by various signals with almost unknown mediators. One of the obligatory steps in the signaling cascade is the activation of K+-influx channels -K+ channels activated by hyperpolarization (KH channels). We thus explored the regulation of these channels in our model system, motor cell protoplasts from Samanea saman, using patch-clamp in the "whole cell" configuration. (a) The most novel finding was that the activity of KH channels in situ varied with the time of the day, in positive correlation with cell swelling: in Extensor cells KH channels were active in the earlier part of the day, while in Flexor cells only during the later part of the day; (b) High internal pH promoted the activity of these channels in Extensor cells, opposite to the behavior of the equivalent channels in guard cells, but in conformity with the predicted behavior of the putative KH channel, cloned from S. saman recently; (c) HIgh external K+ concentration increased (KH channel currents in Flexor cells. BL depolarized the Flexor cells, as detected in cell-attached patch-clamp recording, using KD channels (the K+-efflux channels) as "voltage-sensing devices". Subsequent Red-Light (RL) pulse followed by Darkness, hyperpolarized the cell. We attribute these changes to the inhibition of the H+-pump by BL and its reactivation by RL, as they were abolished by an H+-pump inhibitor. BL increased also the activity KD channels, in a voltage-independent manner - in all probability by an independent signaling pathway. Blue-Light (BL), which stimulates shrinking of Flexor cells, evoked the IP3 signaling cascade (detected directly by IP3 binding assay), known to mobilize cytosolic Ca2+. Nevertheless, cytosolic Ca2+ . did not activate the KD channel in excised, inside-out patches. In this study we established a close functional similarity of the KD channels between Flexor and Extensior cells. Thus the differences in their responses must stem from different links to signaling in both cell types.
Pathogenicity and Sclerotial Development of Sclerotinia sclerotiorum: Involvement of Oxalic Acid and Chitin Synthesis
Authors: Dickman Martin B. , Yarden Oded
Published: December 2021

Sclerotinia sclerotiorum (Lib.) de Bary is among the world's most successful and omnivorous fungal plant pathogens. Included in the nearly 400 species of plants reported as hosts to this fungus are canola, alfalfa, soybean, sunflower, dry bean and potato. The general inability to develop resistant germplasm with these economically important crops to this pathogen has focused attention on the need for a more detailed examination of the pathogenic determinants involved in disease development. A mechanistic understanding of the successful strategy(ies) used by S. sclerotiorum in colonizing host plants and their linkage to fungal development may provide targets and/or novel approaches with which to design resistant crop plants. This proposal involved experiments which were successful in generating genetically-engineered plants harboring resistance to S. sclerotiorum, the establishment and improvement of molecular tools for the study of this pathogen and the analysis of the linkage between pathogenicity, sclerotial morphogenesis and two biosynthetic pathways: oxalic acid production and chitin synthesis. The highly collaborative project has improved our understanding of S. sclerotiorum pathogenicity, established reliable molecular techniques to facilitate experimental manipilation and generated transgenic plants which are resistant to this econimically important fungus.
Price Evaluation and Allocation of Water under Alternative Water Rights System - Part II
Authors: Zilberman David , Hochman Eithan
Published: December 2021

This project is a continuation of US 2081-91. Together they develop a conceptual and empirical framework to analyze alternative forms of water reform that lead to efficient pricing of water. Our analysis demonstrates that the transition from water rights systems to water trading may lead to improved resource allocation even when overall availability of water resources declines. We introduce two systems of water trading, passive markets and active markets, and show that passive markets lead to efficient resource allocation with lower transaction costs. We demonstrate that both methods of trading are superior to block pricing. We identify the political economic situations that would lead to each type of water resource allocation. Examples from Israel and California are used to demonstrate the conceptual results.
Extracellular Matrix Molecules of the Eggshell as Related to Eggshell Quality
Authors: Pines Mark , Bar Arieh , Carrino David A. , Caplan Arnold I. , Dennis James A.
Published: December 2021

The extracellular matrix of the mineralizing eggshell contains molecules hypothesized to be regulators biomineralization. To study eggshell matrix molecules, a bank of monoclonal antibodies was generated that bound demineralized eggshell matrix or localized to oviduct epithelium. Immunofluorescence staining revealed several staining patterns for antibodies that recognized secretory cells: staining for a majority of columnar lining cells, staining for a minor sub-set of columnar lining cells, intensified staining within epithelial crypts, and staining of the entire tubular gland. Western blotting with the antibody Epi2 on eggshell matrix showed binding to molecules with the apparent molecular weight of eggshell matrix dermatan sulfate proteoglycan (eggshell DSPG) (Carrino, et al., 1997). Immunoblots of cyanogen bromide-cleaved eggshell DSPG revealed broad band of reactivity that shifted to 25 kDa after chondroitinase digestion; indicating that the Epi2 binding site is located on a fragment which contains dermatan sulfate side chains. Immunogold labeling showed that Epi2 binds to secretory vesicles within the non-ciliated cells of the columnar epithelium, while the antibodies Tg1 and Tg2 bind to secretory vesicles of tubular gland cells. Immunogold labeling of demineralized shell matrix showed binding of Epi2, Tg1, and Tg2 to the matrix of the palisades layer, and showed little reactivity to other regions of the shell matrix. Quantification of the immunogold particles within the eggshell matrix revealed that antibodies Epi2 and Tg1 bind all calcified regions equally while antibody Tg2 has a greater affinity for the baseplate region of the calcium reserve assembly.
Ozone Altered Stomatal/Guard Cell Function: Whole Plant and Single Cell Analysis
Authors: Pell Eva J. , Assmann Sarah M. , Schwartz Amnon , Steinberger Hava
Published: December 2021

Original objectives (revisions from original proposal are highlighted) 1. Elucidate the direct effects O3 and H2O2 on guard cell function, utilizing assays of stomatal response in isolated epidermal peels and whole cell gas exchange. 2. Determine the mechanistic basis of O3 and H2O2 effects on the plasma membrane through application of the electrophysiological technique of patch clamping to isolated guard cells. 3. Determine the relative sensitivity of Israeli cultivars of economically important crops to O3 and determine whether differential leaf conductance responses to O3 can explain relative sensitivity to the air pollutant: transfer of technological expertise to Israel. Background to the topic For a long time O3 has been known to reduce gas exchange in plants; it has however been unclear if O3 can affect the stomatal complex directly. Ion channels are essential in stomatal regulation, but O3 has never before been shown to affect these directly. Major conclusions, solution, achievements 1. Ozone inhibits light-induced stomatal opening in epidermal peels isolated from Vicia faba, Arabidopsis thaliana and Nicotiana tabacum in V. faba plants this leads to reduced assimilation without a direct effect on the photosynthetic apparatus. Stomatal opening is more sensitive to O3 than stomatal closure. 2. Ozone causes inhibition of inward K+ channels (involved in stomatal opening) while no detectable effect is observed o the outward K+ channels (stomatal closure). 3. Hydrogen peroxide inhibits stomatal opening and induces stomatal closure in epidermal peels isolated from Vicia faba. 4. Hydrogen peroxide enhances stomatal closure by increasing K+ efflux from guard cells via outward rectifying K+ channels. 5. Based on epidermal peel experiments we have indirectly shown that Ca2+ may play a role in the guard cell response to O3. However, direct measurement of the guard cell [Ca2+]cyt did not show a response to O3. 6. Three Israeli cultivars of zucchini, Clarita, Yarden and Bareqet, were shown to be relatively sensitive to O3 (0.12 ml1-1 ). 7. Two environmentally important Israeli pine species are adversely affected by O3, even at 0.050 ml1-1 , a level frequently exceeded under local tropospheric conditions. P. brutia may be better equipped than P. halepensis to tolerate O3 stress. 8. Ozone directly affects pigment biosynthesis in pine seedlings, as well as the metabolism of O5 precursors, thus affecting the allocation of resources among various metabolic pathways. 9. Ozone induces activity of antioxidant enzymes, and of ascorbate content i the mesophyll and epidermis cells of Commelina communis L. Implications, both scientific and agricultural We have improved the understanding of how O3 and H2O2 do affect guard cell and stomatal function. We have shown that economical important Israeli species like zucchini and pine are relatively sensitive to O3.
Nonhomologous DNA End-Joining in Plants: Genes and Mechanisms
Authors: Weil Clifford F. , Britt Anne B. , Levy Avraham
Published: December 2021

Repair of DNA breaks is an essential function in plant cells as well as a crucial step in addition of modified DNA to plant cells. In addition, our inability to introduce modified DNA to its appropriate locus in the plant genome remains an important hurdle in genetically engineering crop species.We have taken a combined forward and reverse genetics approach to examining DNA double strand break repair in plants, focusing primarily on nonhomologous DNA end-joining. The forward approach utilizes a gamma-plantlet assay (miniature plants that are metabolically active but do not undergo cell division, due to cell cycle arrest) and has resulted in identification of five Arabidopsis mutants, including a new one defective in the homolog of the yeast RAD10 gene. The reverse genetics approach has identified knockouts of the Arabidopsis homologs for Ku80, DNA ligase 4 and Rad54 (one gene in what proves to be a gene family involved in DNA repair as well as chromatin remodeling and gene silencing)). All these mutants have phenotypic defects in DNA repair but are otherwise healthy and fertile. Additional PCR based screens are in progress to find knockouts of Ku70, Rad50, and Mre11, among others. Two DNA end-joining assays have been developed to further our screens and our ability to test candidate genes. One of these involves recovering linearized plasmids that have been added to and then rejoined in plant cells; plasmids are either recovered directly or transformed into E. coli and recovered. The products recovered from various mutant lines are then compared. The other assay involves using plant transposon excision to create DNA breaks in yeast cells and then uses the yeast cell as a system to examine those genes involved in the repair and to screen plant genes that might be involved as well. This award supported three graduate students, one in Israel and two in the U.S., as well as a technician in the U.S., and is ultimately expected to result directly in five publications and one Masters thesis.
Viral and Host Cell Determinants of Nuclear Import and Export of the Tomato Yellow Leaf Curl Virus in Tomato Plants
Authors: Citovsky Vitaly , Gafni Yedidya
Published: December 2021

Tomato yellow leaf curl geminivirus (TYLCV) is a major pathogen of cultivated tomato, causing up to 100% crop loss in many parts of the world. In Israel, where TYLCV epidemics have been recorded since the 1960' s, this viral disease is well known and has been of economic significance ever since. In recent years, TYLCV outbreaks also occurred in the "New World" - Cuba, The Dominican Republic, and in the USA, in Florida, Georgia and Louisiana. Thus, TYLCV substantially hinders tomato growth throughout the world. Surprisingly, however, little is known about the molecular mechanisms of TYLCV interaction with the host tomato cells. The present proposal, a continuation of the project supported by BARD from 1994, expanded our understanding of the molecular mechanisms by which TYLCV enters the host cell nucleus for replication and transcription and exits it for the subsequent cell-to-cell spread. Our project sought two objectives: I. To study the roles of the viral capsid protein (CP) and host cell factors in TYLCV nuclear import. II. To study the roles of CP and host cell factors in TYLCV nuclear export. Our research toward these goals have produced the following major achievements: . Developed a one-hybrid assay for protein nuclear export and import (#3 in the List of Publications). . Identified a functional nuclear export signal (NES) in the capsid protein (CP) of TYLCV (#3 in the List of Publications). . Discovered homotypic interactions between intact TYLCV CP molecules and analyzed these interactions using deletion mutagenesis of TYLCV CP (#5 in the List of Publications). . Showed developmental and tissue-specific expression of the host factor required for nuclear import of TYLCV CP, tomato karyopherin alpha 1, in transgenic tomato plants (#14 in the List of Publications). . By analogy to nuclear import of TYLCV ,identified an Arabidopsis VIPI protein that participates in nuclear import of Agrobacterium T -complexes via the karyopherin alpha pathway (#4,6, and 8 in the List of Publications). These research findings provided significant insights into (i) the molecular pathway of TYLCV entry into the host cell nucleus, and (ii) the mechanism by which TYLCV is exported from the nucleus for the cell-to-cell spread of infection. Furthermore, the obtained knowledge will help to develop specific strategies to attenuate TYLCV infection, for example, by blocking viral entry into and/or exit out of the host cell nucleus. Also, as much of our findings is relevant to all geminiviruses, new anti- TYLCV approaches developed based on the results of our research will be useful to combat other members of the Geminivirus family. Finally, in addition to the study of TYLCV nuclear import and export, our research contributed to our understanding of general mechanisms for nucleocytoplasmic shuttling of proteins and nucleic acids in plant cells.
Potentiation of pest control by insect immunosuppression
Authors: Chejanovsky Nor , Webb Bruce A.
Published: December 2021

Our original aims were to elucidate the mechanisms through which the immunosuppressive insect virus, the Campoletis sonorensis polydnavirus (CsV) promotes replication of a well-characterized pathogenic virus, the Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in hosts that are mildly or non-permissive to virus replication. According to the BARD panels criticism we modified our short-term goals (see below). Thus, in this feasibility study (one-year funding) we aimed to show that: 1. S. littoralis larvae mount an immune response against a baculovirus infection. 2. Immunosuppression of an insect pest improves the ability of a viral pathogen (a baculovirus) to infect the pest. 3. S. littoralis cells constitute an efficient tool to study some aspects of the anti- viral immune response. We achieved the above objectives by: 1. Finding melanized viral foci upon following the baculoviral infection in S . littoralis larvae infected with a polyhedra - positive AcMNPV recombinant that expressed the GFP gene under the control of the Drosophila heat shock promoter. 2. Studying the effect of AcMNPV-infection in S . littoralis immunosuppressed by parasitation with the Braconidae wasp Chelonus inanitus that bears the CiV polydna virus, that resulted in higher susceptibility of S. littoralis to AcMNPV- infection. 3. Proving that S. littoralis hemocytes resist AcMNPV -infection. 4. Defining SL2 as a granulocyte-like cell line and demonstrating that as littoralis hemocytic cell line undergoes apoptosis upon AcMNPV -infection. 5. Showing that some of the recombinant AcMNPV expressing the immuno-suppressive polydna virus CsV- vankyrin genes inhibit baculoviral-induced lysis of SL2 cells. This information paves the way to elucidate the mechanisms through which the immuno- suppressive polydna insect viruses promote replication of pathogenic baculoviruses in lepidopteran hosts that are mildly or non-permissive to virus- replication by: - Assessing the extent to which and the mechanisms whereby the immunosuppressive viruses, CiV and CsV or their genes enhance AcMNPV replication in polydnavirus- immunosuppressed H. zea and S. littoralis insects and S. littoralis cells. - Identifying CiV and CsV genes involved in the above immunosuppression (e.g. inhibiting cellular encapsulation and disrupting humoral immunity). This study will provide insight to the molecular mechanisms of viral pathogenesis and improve our understanding of insect immunity. This knowledge is of fundamental importance to controlling insect vectored diseases of humans, animals and plants and essential to developing novel means for pest control (including baculoviruses) that strategically weaken insect defenses to improve pathogen (i.e. biocontrol agent) infection and virulence.
Microbial Communities Active in Soil-Induced Systemic Plant Disease Resistance
Authors: Michel Jr. Frederick C. , Hoitink Harry A.J. , Hadar Yitzhak , Minz Dror
Published: December 2021

Induced Systemic Resistance (ISR) is a highly variable property that can be induced by compost amendment of potting media and soils. For example, previous studies showed that only 1 of 79 potting mixes prepared with different batches of mature composts produced from several different types of solid wastes were able to suppress the severity of bacterial leaf spot of radish caused by Xanthomonas campestris pv. armoraciae compared with disease on plants produced in a nonamended sphagnum peat mix. In this project, microbial consortia in the rhizosphere of plants grown in ISR-active compost-amended substrates were characterized. The plants used included primarily cucumber but also tomato and radish. Rhizosphere microbial consortia were characterized using multiple molecular tools including DGGE (Israel) and T -RFLP (Ohio) in both ISR-active field plots and potting media. Universal as well as population-specific bacterial and fungal PCR primers were utilized. T -RFLP analyses using universal bacterial primers showed few significant differences in overall bacterial community composition in ISR-active and inactive substrates (Ohio). In addition, the community members which were significantly different varied when different ISR-activecomposts were used (Ohio). To better characterize the shifts in microbial community structure during the development of ISR, population specific molecular tools were developed (Israel, Ohio).-PCR primers were designed to detect and quantify bacterial groups including Pyrenomycetes, Bacillus, Pan toea, Pseudomonas, Xanthomonas and Streptomyces as well as Trichoderma and Fusarium; two groups of fungi that harbor isolates which are ISR active (Isreal and Ohio). Bacterial consortia associated with cucumber plants grown in compost-amended potting mixtures were shown to be dominated by the phylogenetic taxon Bacteroidetes, including members of the genus Chryseobacterium, which in some cases have been shown to be involved in biocontrol (Israel). Nested-PCR-DGGE analyses coupled with long l6S rDNA sequencing, demonstrated that the Chryseobacteriumspp. detected on seed and the root in compost-amended treatments were derived from the compost itself. The most effective ISR inducing rhizobacterial strains were identified as Bacillus sp. based on partial sequencing of l6S rDNA. However, these strains were significantly less effective in reducing the severity of disease than Trichoderma hamatum382 (T382). A procedure was developed for inoculation of a compost-amended substrate with T -382 which consistently induced ISR in cucumber against Phytophthora blight caused by Phytophthora capsiciand in radish against bacterial spot (Ohio). Inoculation of compost-amended potting mixes with biocontrol agents such as T -382 and other microbes that induce systemic resistance in plants significantly increased the frequency of systemic disease control obtained with natural compost amendments.
Host Ammonification by Postharvest Pathogens and its Contribution to Fungal Colonization and Symptom Development
Authors: Prusky Dov , Vaillancourt Lisa , Fluhr Robert
Published: December 2021

Postharvest decay of fruits and vegetables caused by pathogenic and saprophytic fungi significantly impairs the quality and quantity of fresh produce brought to market. Consequently, there is considerable interest in identifying factors that determine the susceptibility of these commodities to pathogen infection. Insidious postharvest decays remain quiescent during fruit growth and harvest, but activate during the postharvest period. A key response to the physiological changes occurring during fruit ripening is the initiation of ammonium secretion by the pathogen. Ammonium ions at the infection site (ammonification) have subsequent effects on both the pathogen and the host. An accompanying alkalinization process resulting from ammonia accumulation contributes to pathogenicity, since some important fungal virulence factors, (such as pectate lyase in Colletotrichum sp.), are significantly expressed only under alkaline conditions. In this proposal, investigated the mechanisms by which ammonification and alkalinization of infected tissues by the pathogen affect the host’s defense response to fungal attack, and instead increase compatibility during postharvest pathogen-host interactions. Our hypotheses were:1) that host signals, including ripening-related changes, induce secretion of ammonia by the pathogen; 2) that ammonia accumulation, and the resultant environmental alkalinization regulate the expression of fungal virulence genes that are essential for postharvest rot development; 3) that ammonification enhanced fungal colonization, by “suppression of host responses”, including production of reactive oxygen species, activation of superoxide, and polyphenol oxidase production. Our objectives were: to analyze: 1) factor(s) which activate the production and secretion of ammonia by the fungus; 2) fungal gene(s) that play role(s) in the ammonification process; 3) the relationship between ammonification and the activation of host defense response(s) during pathogen colonization; and 4) analyze hostgene expression in alkalinized regions of fruits attacked by hemibiotrophic fungi.
Characterization of the biochemical basis of host specificity of Penicillium digitatum and Penicillium italicum on citrus fruit
Authors: Droby Samir , Gottwald Tim R. , Stange Richard , Lewinsohn Efraim , McCollum T. Gregory
Published: December 2021

l. This research demonstrates that citrus fruit volatiles play an important role in host recognition by P. digitatum and P. italicum. 2. Volatiles derived from non-host fruits and vegetables (apple, pear, tomato, pepper, strawberry and avocado) had no effect on promotion of spore germination and growth of citrus pathogens. 3. Citrus volatiles have a specific stimulatory effect solely on P. digitatum and P. italicum. Non-citrus pathogens such as P. expansum and B. cinerea not affected orinhibited by the volatile materials. The specific stimulatory effect of fruit peelvolatiles on citrus pathogens and inhibitory effect on non-pathogens indicateimport ant role of volatile compounds in the host selectivity of citrus postharvestpathogens. 4. Comparative CG-MS quantification was per formed and identification of volatileconstituents of citrus commercial oils, peel extracts and the headspace of thewounded fruits was completed. Monoterpenehydrocarbons (limonene, a-pinene,sabinene, and myrcene) were the most abundant in all volatiles regardless of thesource.  5. Our results demonstrated stimulation of germination and germ tube growth in both P. digitatum and P. italicum by limonene, myrcene, a-pinene, and b-pinene). Limonenewas show n to be the most efficient in induction of germination and growth in bothpathogens. 6. P. digitatum spores placed on the surface of lemon fruit, adjacent to a wounded oil gland, were induced to germinate and grow, thus supporting all the in vitro results and demonstrating that the phenomenon of stimulation of germination and growth occurs on the fruit. 7. We established that P. digitatum is capable of biotransformation of limonene to a terpineol. a-terpinel was proved to be involved in induction of fungal sporulation process. 8. Chemotropism (directional growth) of P. digitatum towards the volatiles released from the oil glands on fruit surface was demonstrated. 9. Citrus germplasm screening work for fruit susceptibility/resistance for P. digitatum infection showed no definitive results regarding host range and susceptibility.Although the sour orange selections appear to show higher resistance to infection and decay development.  10. We demonstrated that P. expansum, non citrus pathogen, is capable of germinating in citrus fruit surface wounds, but it strongly induced host resistance mechanisms which restrict it growth and prevented decay development. The host (citrus fruit) reacted strongly by production of ROS. On the other hand, P. digitatum seems to actively suppress host natural resistance mechanisms possibly through inhibiting the production of ROS production.