Some Physiological Aspects Of The Soybean - Phytophthora Megasperma F Sp Glycinea Interaction, With Special Reference To The Phytoalexin, Glyceollin

The interaction of soybean cultivars (Glycine max) with Phytophthora megasperma f.sp. glycinea (Pmg) races is governed by single host genes (Rps) and is consistent with the gene-for-gene hypothesis. Using the near isogenic cultivars Harosoy ({dollar}rps\sb1{dollar}, susceptible to race 1) and Harosoy 63 ({dollar}Rps\sb1{dollar}, resistant) and Pmg race 1 it was demonstrated that the {dollar}Rps\sb1{dollar} gene is expressed in hypocotyls and roots of light and dark grown seedlings, in green cotyledons and leaves but not in immature leaves. Leaves of cv. Harosoy became resistant with age. The phytoalexins, glyceollin isomers I, II and III, accumulated rapidly in resistant responses. Proportions of the glyceollin isomers varied with the organ, exposure to light, interaction type and incubation period. The three isomers, also differed in their toxicities to Pmg. Glyceollin I was almost twice as inhibitory as glyceollin II and III to mycelial growth in vitro. An isolate of Pmg race 1 (Isolate 1.1) was obtained that was twice as tolerant to glyceollin I and III as race 1. Evidence was obtained for variability in morphology, growth, tolerance to glyceollin I and aggressiveness of single-zoospore progeny of race 1 and Isolate 1.1, that may be accounted for by cytoplasmic factors.;From pulse and pulse-chase experiments using L- (U{dollar}\sp{lcub}14{rcub}{dollar}C) -phenylalanine as precursor it is concluded that accumulation of higher levels of glyceollin I in resistant than in susceptible responses is due to differences in rates of biosynthesis. Rapid metabolism, which was not constitutive, was demonstrated in all interactions and controls. This is consistent with differences in phenylalanine ammonia-lyase (PAL) activity demonstrated in resistant and susceptible responses. PAL activity also was correlated with changes in glyceollin production and susceptibility at elevated temperatures. Differential effects of temperature on growth and glyceollin I sensitivity of Pmg races were demonstrated also. In some race-cultivar combinations reaction types may be related to the effect of temperature on production and sensitivity to glyceollin I.;A model is presented that attempts to accommodate the physiological data obtained in this study with the requirements of the gene-for-gene relationship of host-pathogen interactions

Systemic acquired resistance in soybean is regulated by two proteins, Orthologous to Arabidopsis NPR1

<p>Abstract</p> <p>Background</p> <p>Systemic acquired resistance (SAR) is induced in non-inoculated leaves following infection with certain pathogenic strains. SAR is effective against many pathogens. Salicylic acid (SA) is a signaling molecule of the SAR pathway. The development of SAR is associated with the induction of pathogenesis related (<it>PR</it>) genes. Arabidopsis <it>non-expressor </it>of <it>PR1 </it>(<it>NPR1</it>) is a regulatory gene of the SA signal pathway <abbrgrp><abbr bid="B1">1</abbr><abbr bid="B2">2</abbr><abbr bid="B3">3</abbr></abbrgrp>. SAR in soybean was first reported following infection with <it>Colletotrichum trancatum </it>that causes anthracnose disease. We investigated if SAR in soybean is regulated by a pathway, similar to the one characterized in Arabidopsis.</p> <p>Results</p> <p>Pathogenesis-related gene <it>GmPR1 </it>is induced following treatment of soybean plants with the SAR inducer, 2,6-dichloroisonicotinic acid (INA) or infection with the oomycete pathogen, <it>Phytophthora sojae</it>. In <it>P. sojae</it>-infected plants, SAR was induced against the bacterial pathogen, <it>Pseudomonas syringae </it>pv. glycinea. Soybean <it>GmNPR1-1 </it>and <it>GmNPR1-2 </it>genes showed high identities to Arabidopsis <it>NPR1</it>. They showed similar expression patterns among the organs, studied in this investigation. <it>GmNPR1-1 </it>and <it>GmNPR1-2 </it>are the only soybean homologues of <it>NPR1</it>and are located in homoeologous regions. In <it>GmNPR1-1 </it>and <it>GmNPR1-2 </it>transformed Arabidopsis <it>npr1-1 </it>mutant plants, SAR markers: (i) <it>PR-1 </it>was induced following INA treatment and (ii) <it>BGL2 </it>following infection with <it>Pseudomonas syringae </it>pv. tomato (<it>Pst</it>), and SAR was induced following <it>Pst </it>infection. Of the five cysteine residues, Cys⁸², Cys¹⁵⁰, Cys¹⁵⁵, Cys¹⁶⁰, and Cys²¹⁶involved in oligomer-monomer transition in NPR1, Cys²¹⁶ in GmNPR1-1 and GmNPR1-2 proteins was substituted to Ser and Leu, respectively.</p> <p>Conclusion</p> <p>Complementation analyses in Arabidopsis <it>npr1-1 </it>mutants revealed that homoeologous <it>GmNPR1-1 </it>and <it>GmNPR1-2 </it>genes are orthologous to Arabidopsis <it>NPR1</it>. Therefore, SAR pathway in soybean is most likely regulated by <it>GmNPR1 </it>genes. Substitution of Cys²¹⁶residue, essential for oligomer-monomer transition of Arabidopsis NPR1, with Ser and Leu residues in GmNPR1-1 and GmNPR1-2, respectively, suggested that there may be differences between the regulatory mechanisms of GmNPR1 and Arabidopsis NPR proteins.</p

Sequence based polymorphic (SBP) marker technology for targeted genomic regions: its application in generating a molecular map of the Arabidopsis thaliana genome

<p>Abstract</p> <p>Background</p> <p>Molecular markers facilitate both genotype identification, essential for modern animal and plant breeding, and the isolation of genes based on their map positions. Advancements in sequencing technology have made possible the identification of single nucleotide polymorphisms (SNPs) for any genomic regions. Here a sequence based polymorphic (SBP) marker technology for generating molecular markers for targeted genomic regions in Arabidopsis is described.</p> <p>Results</p> <p>A ~3X genome coverage sequence of the <it>Arabidopsis thaliana </it>ecotype, Niederzenz (Nd-0) was obtained by applying Illumina's sequencing by synthesis (Solexa) technology. Comparison of the Nd-0 genome sequence with the assembled Columbia-0 (Col-0) genome sequence identified putative single nucleotide polymorphisms (SNPs) throughout the entire genome. Multiple 75 base pair Nd-0 sequence reads containing SNPs and originating from individual genomic DNA molecules were the basis for developing co-dominant SBP markers. SNPs containing Col-0 sequences, supported by transcript sequences or sequences from multiple BAC clones, were compared to the respective Nd-0 sequences to identify possible restriction endonuclease enzyme site variations. Small amplicons, PCR amplified from both ecotypes, were digested with suitable restriction enzymes and resolved on a gel to reveal the sequence based polymorphisms. By applying this technology, 21 SBP markers for the marker poor regions of the Arabidopsis map representing polymorphisms between Col-0 and Nd-0 ecotypes were generated.</p> <p>Conclusions</p> <p>The SBP marker technology described here allowed the development of molecular markers for targeted genomic regions of Arabidopsis. It should facilitate isolation of co-dominant molecular markers for targeted genomic regions of any animal or plant species, whose genomic sequences have been assembled. This technology will particularly facilitate the development of high density molecular marker maps, essential for cloning genes based on their genetic map positions and identifying tightly linked molecular markers for selecting desirable genotypes in animal and plant breeding experiments.</p

Painter: Teaching Auto-regressive Language Models to Draw Sketches

Large language models (LLMs) have made tremendous progress in natural language understanding and they have also been successfully adopted in other domains such as computer vision, robotics, reinforcement learning, etc. In this work, we apply LLMs to image generation tasks by directly generating the virtual brush strokes to paint an image. We present Painter, an LLM that can convert user prompts in text description format to sketches by generating the corresponding brush strokes in an auto-regressive way. We construct Painter based on off-the-shelf LLM that is pre-trained on a large text corpus, by fine-tuning it on the new task while preserving language understanding capabilities. We create a dataset of diverse multi-object sketches paired with textual prompts that covers several object types and tasks. Painter can generate sketches from text descriptions, remove objects from canvas, and detect and classify objects in sketches. Although this is an unprecedented pioneering work in using LLMs for auto-regressive image generation, the results are very encouraging

The Genome Sequence of the Fungal Pathogen Fusarium virguliforme That Causes Sudden Death Syndrome in Soybean

Fusarium virguliforme causes sudden death syndrome (SDS) of soybean, a disease of serious concern throughout most of the soybean producing regions of the world. Despite the global importance, little is known about the pathogenesis mechanisms of F. virguliforme. Thus, we applied Next-Generation DNA Sequencing to reveal the draft F. virguliforme genome sequence and identified putative pathogenicity genes to facilitate discovering the mechanisms used by the pathogen to cause this disease

Genetic architecture and evolution of the mating type locus in fusaria that cause soybean sudden death syndrome and bean root rot

Fusarium tucumaniae is the only known sexually reproducing species among the seven closely related fusaria that cause soybean sudden death syndrome (SDS) or bean root rot (BRR). In a previous study, laboratory mating of F. tucumaniae yielded recombinant ascospore progeny but required two mating-compatible strains, indicating that it is heterothallic. To assess the reproductive mode of the other SDS and BRR fusaria, and their potential for mating, whole-genome sequences of two SDS and one BRR pathogen were analyzed to characterize their mating type (MAT) loci. This bioinformatic approach identified a MAT1-1idiomorph in F. virguliforme NRRL 22292 and MAT1-2 idiomorphs in F. tucumaniae NRRL 34546 and F. azukicola NRRL 54364. Alignments of the MAT loci were used to design PCR primers within the conserved regions of the flanking genes APN1 and SLA2, which enabled primer walking to obtain nearly complete sequences of the MAT region for six MAT1-1 and five MAT1-2 SDS/BRR fusaria. As expected, sequences of the highly divergent 4.7 kb MAT1-1 and 3.7 kb MAT1-2 idiomorphs were unalignable. However, sequences of the respective idiomorphs and those that flank MAT1-1 and MAT1-2 were highly conserved. In addition to three genes at MAT1-1 (MAT1-1-1, MAT1-1-2, MAT1-1-3) and two at MAT1-2 (MAT1-2-1, MAT1-2-3), the MAT loci of the SDS/BRR fusaria also include a putative gene predicted to encode for a 252 amino acid protein of unknown function. Alignments of the MAT1-1-3 and MAT1-2-1 sequences were used to design a multiplex PCR assay for the MAT loci. This assay was used to screen DNA from 439 SDS/BRR isolates, which revealed that each isolate possessed MAT1-1 or MAT1-2, consistent with heterothallism. Both idiomorphs were represented among isolates of F. azukicola, F. brasiliense, F. phaseoli and F. tucumaniae, whereas isolates of F. virguliforme and F. cuneirostrum were only MAT1-1 and F. crassistipitatum were only MAT1-2. Finally, nucleotide sequence data from the RPB1 and RPB2 genes were used to date the origin of the SDS/BRR group, which was estimated to have occurred about 0.75 Mya (95% HPD interval: 0.27, 1.68) in the mid-Pleistocene, long before the domestication of the common bean or soybean

Tanscriptomic Study of the Soybean-Fusarium virguliforme Interaction Revealed a Novel Ankyrin-Repeat Containing Defense Gene, Expression of Whose during Infection Led to Enhanced Resistance to the Fungal Pathogen in Transgenic Soybean Plants

Fusarium virguliforme causes the serious disease sudden death syndrome (SDS) in soybean. Host resistance to this pathogen is partial and is encoded by a large number of quantitative trait loci, each conditioning small effects. Breeding SDS resistance is therefore challenging and identification of single-gene encoded novel resistance mechanisms is becoming a priority to fight this devastating this fungal pathogen. In this transcriptomic study we identified a few putative soybean defense genes, expression of which is suppressed during F. virguliformeinfection. The F. virguliforme infection-suppressed genes were broadly classified into four major classes. The steady state transcript levels of many of these genes were suppressed to undetectable levels immediately following F. virguliforme infection. One of these classes contains two novel genes encoding ankyrin repeat-containing proteins. Expression of one of these genes, GmARP1, during F. virguliforme infection enhances SDS resistance among the transgenic soybean plants. Our data suggest that GmARP1 is a novel defense gene and the pathogen presumably suppress its expression to establish compatible interaction