Donors Of Resistance Research Articles

Genetic diversity, population structure in a historical panel of Brazilian soybean cultivars.

Soybean [Glycine max (L.) Merrill] is one of the most widely grown legumes in the world, with Brazil being its largest producer and exporter. Breeding programs in Brazil have resulted from multiple cycles of selection and recombination starting from a small number of USA cultivar ancestors in the 1950s and 1960s years. This process has led to the successful adaptation of this crop to tropical conditions, a phenomenon known as tropicalization. Many studies describe a narrow genetic background in Brazilian soybean cultivars. Various factors can affect the genetic diversity in species, especially in cultivated crops, such as the reproduction type, artificial selection, and the number and sources of variability in the breeding programs. In turns, the genetic diversity can affect the linkage disequilibrium blocks (LD) patterns and, consequently, molecular breeding strategies for selection of target loci for agronomic traits. We used high-throughput genotyping with SoySNP50K Illumina SNP markers to assess a collection of 370 Brazilian soybean accessions covering more than 60 years of soybean breeding in Brazil. Our goal was to investigate population structure and genetic diversity in the Brazilian germplasm, detect patterns of LD blocks, and identify regions presenting signals of selective swaps linked with quantitative trait loci (QTLs) of agronomic interest. Population structure analysis revealed two major groups among all genotypes, primarily differentiated by the year of release, separating old and new cultivars (before and after 2000´s years), and by growth habit (stem termination type-SST). The group I comprises about 75% of the panel and includes cultivars release before 2000`s years, including the oldest cultivars released in Brazil, most of which exhibit a determinate growth habit and maturity groups VI and VII. Group II includes only 83 materials, but shows higher levels of diversity than group I, representing most recent introductions in Brazilian germplasm. Further analysis of substructure within Group I, identified seven subgroups with no clear trend for segregation based on maturity group, STT or year of release. Instead, these subgroups were based on the contribution of key donors of disease resistance and adaptability, as soybean cultivation expanded from the South to Central region of Brazil. This finding is consistent with the history of soybean expansion in Brazil. We identified 123 genomic regions under selection among the groups of Brazilian cultivars associated with 440 quantitative trait loci (QTLs), revealing regions fixed across the breeding process associated with yield, disease resistance, water efficiency use, and others.

VIR potato doublet collection, its significance for breeding

Relevance and research material. In 2023, it was 100 years since the beginning of the collection, study and preservation of the world doublet collection of potatoes (UNU, registration USU_505851) at the Polar Experimental Station of the VIR branch. This is one of the oldest and unique potato collections, the preservation of which is carried out in the field. The first potato samples began to enter the collection in 1923. Now the potato doublet collection has 3200 samples. It includes breeding varieties, hybrids, cultivated South American potato species Solanum andigenum Juz. et Buk, Solanum chilotanum Hawkes.Results. The collection is a unique genetic material that is of high importance in solving issues of improving the efficiency of agriculture in the country. As part of the field collection of potatoes, the source material for dangerous quarantine objects is quite widely presented: potato cancer (Synchytrium endobioticum (Schilb.) Persiva) and globoderosis (Globodera rostochiensis Woll.). There are donors of late blight resistance (Phytophthora infestans (Mont.) de Bary.). There is a source material in the collection that has economically valuable characteristics: precocity, frost resistance, yield, marketability. Varieties with a high amount of phenolic compounds in the tuber pulp are also included in the field doublet collection. Such varieties are suitable for dietary nutrition and can be used in the prevention of a number of diseases.Conclusion. The collection of the collection is of great importance for applied research and for ensuring food security of the region and the country as a whole.

Relative resistance of the initial material of peas to pea weevil (Bruchus Pisorum L.) in the Donbass

Yield losses caused by pests pose a serious threat when cultivating peas. From the earliest stages until maturing, pea plants and seeds are seriously damaged. The pea weevil (Bruchus pisorum L.) is among the most dangerous pests. According to some researchers, its harmfulness can significantly reduce yields by 30–40 % in some years. The purpose of the current study was to identify a seed damage rate (Bruchus pisorum L.) of pea collection samples with different vegetation periods, to select valuable initial material with subsequent use as a donor of increased resistance to the harmfulness of pea weevil. The weather conditions during the years of study (2021–2023) were different, which made it possible to determine the damage rate to pea forms of different maturity groups. There has been found that the mid-maturing group with a vegetation period of 65–85 days was the most vulnerable. The general damage rate was 36.8 %. The samples with a vegetation period of 51–60 days were more resistant to the pest. Seed damage rate was on average 22.9 %, which was 13.9 % less than that of mid-maturing forms. According to this criterion, the samples ‘Stengolt’, ‘Charlston’, ‘Rodegune’, ‘Imposant’, ‘Pu-726’ are of significant breeding value. According to the indicator of pest activity, there have been identified the forms ‘Stengolt’, ‘Charlston’, ‘Pu-726’, ‘Imposant’, ‘Exsellans’. The samples ‘Stengolt’, ‘Pu-726’, ‘Imposant’ are of particular interest for practical breeding since they carry complex resistance in the genotype, both by selectivity and by larvae activity inside the seed. The identified samples can be used in future breeding programs as donors of relative resistance. The analysis has revealed a reliable high correlation between damage rate of pea seeds and the length of a vegetation period of the studied forms, a selectivity rate of pea samples by pea weevil and larvae activity inside the seed.

Breeding assessment of experimental downy mildew-resistant sunflower hybrids

To determine the resistance of new sunflower starting materials to downy powdery mildew using differentiator lines. To determine the stability of plant performance and height in F1 derived from lines - donors of resistance to downy mildew in three crossing types in comparison with reference accessions bred by us. Methods. Using our own methods, to assess the presence of genetic determinants Pl, which control resistance of lines and hybrids to the pathogens of downy mildew races 710, 730, and 330, which are distributed in the eastern Forest-steppe of Ukraine, in an artificial climate. Field trials in 2022-2023 were done with assessments of major economically valuable features by conventional methods. Results. The results of the breeding assessments of the new sunflower starting materials for resistance to downy mildew in the laboratory and field trials were obtained. The effect of donors of resistance to the pathogen, Plasmopara helianthi, such as X06134ВPl, X06135ВPl, and X777БPl, on the endurance of new F1s with a significant increase in the plant performance compared to the check accessions (simple hybrid “Kadet” and three-line hybrid “Zlatson”) was proven. Negative selection was demonstrated for plant height: new plants were not taller than reference ones. It has a positive effect on plant height in an agrocenosis, which does not decrease its yield when grown in the conditions of current agriculture production. Conclusions. Promising reference accessions of resistance to downy mildew were identified: line X06135ВPl (minidisc), X06134ВPl (multidisc), and X777BPl (pollen sterility fixer), which are immune to the causative agent of downy mildew local races. The resistance of the best new hybrids to downy mildew in comparison with the specified references was characterized. Experimental hybrids of three groups: restored simple hybrids, sterile simple hybrids, and hybrid combinations obtained by artificial hybridization, were created. They are noticeable for high plant performance and optimal height and significantly better than the existing reference hybrids, “Kadet” and “Zlatson”.

Comprehensive overview of host plant resistance and its progress in wilt resistance in castor bean (Ricinus communis L.)

Castor bean, a non-edible monotypic species known for its unique hydroxy fatty acid, is susceptible to a range of pathogens. Wilt caused by Fusarium oxysporum f. sp. ricini is the most complex and destructive disease. Chemical control of wilt has proven ineffective due to the systemic nature of the disease and the seed and soil borne nature of the pathogen. Physical, chemical, biological, and integrated management methods have shown only limited success in controlling wilt. Host plant resistance, however, stands out as the most promising strategy, offering a viable pathway for the genetic improvement of castor beans for wilt resistance. Screening techniques are well established, and several resistant donors have already been identified. While significant progress has been made in understanding the inheritance of wilt resistance, a complete understanding of its genetic mechanisms still requires further research. Single Nucleotide Polymorphism (SNP) markers and genomic regions linked to wilt resistance have been successfully identified. Reniform nematode (Rotylenchulus reniformis) has been identified as a predisposing factor for wilt, and genomic regions linked to nematode resistance have also been identified. However, Marker-assisted selection has not yet been utilized to develop wilt-resistant castor varieties. Further research is required to explore the pathogen diversity, host-pathogen interactions, and mechanisms underlying wilt resistance including the metabolites responsible for preventing the emergence of new pathogenic races and ensuring long-term protection against wilt.

Identification of powdery mildew resistance quantitative trait loci in melon and development of resistant near-isogenic lines through marker-assisted backcrossing

BackgroundMelon (Cucumis melo L.), an important cucurbit crop, faces production limitations due to powdery mildew (PM). Developing resistant varieties offers a sustainable, genetics-based alternative to chemical treatments. Therefore, identifying PM resistance quantitative trait loci (QTL) and creating trait-associated markers are essential for efficient melon PM resistance improvement through marker-assisted backcrossing (MABC).ResultsThree F2 populations, A6, B2, and C4, were generated for QTL mapping of PM resistance. Major QTL were identified on chromosome 2 in A6, chromosome 5 in B2, and chromosomes 5 and 12 in C4. A series of TaqMan® assays targeting regions on chromosomes 2, 5, and 12 were developed and validated for foreground and recombinant selection, complemented by the double digest restriction-site associated DNA genotyping system to evaluate the recurrent parent genome recovery. Three MABC programs using resistant donor parents from A6 and C4 crossed with elite susceptible recurrent parents with green and orange fruit flesh were implemented. After two to three cycles of MABC, individual QTL was successfully introgressed into elite genetic backgrounds, giving six PM resistance lines in each green- and orange-fleshed background. PM inoculation on the twelve near-isogenic lines confirmed their resistance to PM.ConclusionsWe have identified major PM resistance QTL for melon on chromosomes 2, 5, and 12 and have introgressed individual QTL to elite genetic backgrounds using MABC in three and a half years. This study demonstrates the power of combining high-throughput genotyping with breeding efforts and showcases the efficiency of molecular breeding.

Tetracycline resistance gene transfer from Escherichia coli donors to Salmonella Heidelberg in chickens is impacted by the genetic context of donors

Chicken ceca are a rich source of bacteria, including zoonotic pathogens such as Salmonella enterica. The microbiota includes strains/species carrying antimicrobial resistance genes and horizontal transfer of resistance determinants between species may increase the risk to public health and farming systems. Possible sources of these antimicrobial resistance donors – the eggshell carrying bacteria from the hen vertically transmitted to the offspring, or the barn environment where chicks are hatched and raised – has been little explored. In this study, we used Salmonella enterica serovar Heidelberg to evaluate if layer chicks raised in different environments (using combinations of sterilized or non-sterile eggs placed in sterilized isolation chambers or non-sterile rooms) acquired transferable tetracycline resistance genes from surrounding bacteria, especially Escherichia coli. Two-day old chicks were challenged with an antibiotic-susceptible S. Heidelberg strain SH2813nalR and Salmonella recovered from the cecum of birds at different timepoints to test the in vivo acquisition of tetracycline resistance. Tetracycline-resistant E. coli isolates recovered from birds from the in vivo experiment were used to test the in vitro transfer of tetracycline resistance genes from E. coli to Salmonella. Even though Salmonella SH2813nalR colonized the 2-day old chicks after oral challenge, tetracycline-resistant Salmonella transconjugants were not recovered, as previously observed. In vitro experiments provided similar results. We discuss several hypotheses that might explain the absence of transconjugants in vitro and in vivo, despite the presence of diverse plasmids in the recovered E. coli. The factors that can inhibit/promote antimicrobial resistance transfers to Salmonella for different plasmid types need further exploration.

Marker-based identification of potential scab resistance donors in Latvia apple collection

Marker-based identification of potential scab resistance donors in Latvia apple collection

Interspecific hybridization and cell engineering of lettuce (Lactuca L.)

Lactuca sativa L. is a leafy vegetable crop of the Asteraceae family, widely cultivated throughout the world. The main breeding trends for lettuce include higher yields, better taste quality, earliness, and resistance to abiotic and biotic stressors. Some wild Lactuca spp. have actively been employed by lettuce breeders as donors of resistance to various diseases. Conventional and biotechnological breeding methods are both currently used to develop new lettuce cultivars. This is an overview of the main advances in the production of interspecific Lactuca hybrids, including the use of cell and tissue culture techniques, and genetic engineering. Studying artificial hybridization and natural populations makes it possible to identify evolutionary relationships among various Lactuca spp. Somatic hybridization is an overlooked but promising technology in Lactuca breeding: it allows a breeder to obtain a wider range of variations, and is beyond the strict control by GMO laws. This technique faces problems associated with complicated protoplast regeneration and the loss of reproductive ability in hybrids. Genome-editing methods are more effective and better controllable, but society is still wary of any interference with the plant genome and legally regulates the sale of GM products as food. Thus, researchers are challenged with the task to improve these techniques.

Correction: Identification and molecular validation of Bean Common Mosaic Virus Resistant Donors in Common Bean (Phaseolus vulgaris L.)

Correction: Identification and molecular validation of Bean Common Mosaic Virus Resistant Donors in Common Bean (Phaseolus vulgaris L.)

Cysteine-Rich Peptide Genes of Wheatgrass <i>Thinopyrum elongatum</i>

Cysteine-rich peptides play an important role in the plant defense system. The aim of the present work was to search in silico for genes encoding antimicrobial and signaling peptides in the genome of Thinopyrum elongatum (Host) D.R. Dewey (2n = 14, EE) − a wild grass species with high resistance to pathogens and abiotic stress. Bioinformatic analysis revealed 154 new genes of antimicrobial and signaling peptide precursors belonging to 9 families in Th. elongatum genome. Introns were detected in a number of cysteine-rich peptide genes. The structure of peptide precursors and localization of peptide genes in wheat chromosomes were determined. The greatest similarity of the sequences of Th. elongatum peptides with homologous peptides of plants of the genera Triticum and Aegilops was shown, which confirms the cytogenetic data on the relatedness of genome E with genome D and similar genomes. The results obtained contribute to the characterization of molecular components of the immune system of Th. elongatum and will serve as a basis for further studies of resistance mechanisms, as well as for scientifically justified practical use of this species as a resistance donor in wheat breeding.

The point mutation A1387G in the 16S rRNA gene confers aminoglycoside resistance in Campylobacter jejuni and Campylobacter coli.

Thermotolerant Campylobacter spp. are the most frequent cause of foodborne bacterial diarrhea and high-priority antibiotic-resistant pathogens, according to the World Health Organization (WHO). Monitoring revealed current low prevalence of gentamicin resistance in European Campylobacter spp. isolates but substantial presence of gentamicin modifying genes circulating globally. Using a combined approach of natural transformation and whole-genome sequencing, we revealed a novel gentamicin resistance mechanism, namely the point mutation A1387G in the 16S rRNA gene, originally identified in a C. coli isolate from turkey caecal content. The transformation rate of the resistance using genomic DNA of the resistant donor to sensitive recipient C. jejuni and C. coli was ~2.5 log10 lower compared to the control rpsL-A128G point mutation conferring streptomycin resistance. Antimicrobial susceptibility tests showed cross-resistance to apramycin, kanamycin, and tobramycin, with transformants exhibiting more than 4- to 8-fold increased MICs to apramycin and tobramycin and over 64-fold higher MICs to kanamycin compared to wild-type isolates. Although transformants showed 177-1,235 variations relative to the recipient, only the A1387G point mutation in the 16S rRNA was in common. This mutation was causal for resistance, as transformation of a 16S rRNA_A1387G PCR fragment into susceptible isolates also led to resistant transformants. Sanger sequencing of the 16S rRNA genes and Oxford nanopore whole-genome sequencing of transformants identified clones harboring either all three copies with A1387G or a mixed population of wild-type and mutated 16S rRNA gene alleles. Within 15 passages on non-selective medium, transformants with mixed populations of the 16S rRNA gene copies partially reverted to wild type, both geno- and phenotypically. In contrast, transformants harboring the A1387G point mutation in all three 16S rRNA gene copies kept full resistance within at least 45 passages. We speculate that partial acquisition and rapid loss of the point mutation limited its spread among C. spp. isolates. In-depth knowledge on resistance mechanisms contributes to optimal diagnosis and preventative measures.

Identification of false smut – resistant donors in Rice (Oryza sativa L.) and analysis of their morpho-molecular diversity for resistance breeding

False smut disease of rice caused by the pathogen Ustilaginoidea virens is a growing threat to the rice farmers as it affects both quality and quantity. Development of resistant variety becomes difficult, since very few resistant donors were available for false smut resistant breeding programme. Therefore, to identify potential donors for resistance breeding a total of 60 genotypes were screened at hotspot location (Gudalur) during kharif 2023 which led to identification of 12 highly resistant genotypes and the notable ones are Koolavalai, Periya chandikar, Kapikar selection and Earapalli. Genetic variability studies indicated the presence of additive gene action for all the agronomic and disease related traits. Principal component analysis revealed the first 5 principal components collectively contributing 78.79 % of the total variance with disease-related traits contributing significantly to divergence. Ten clusters were delineated using Mahalanobis D2 statistics with clusters IX and V showing higher inter cluster distance (3453.64). Forty-one polymorphic markers were used to analyse the genotypes and The Unweighted Pair Group method with Arithmetic Mean (UPGMA) clustering by Jaccard distance formed 6 clusters. The Bayesian clustering classified the entire population into 2 subpopulations. False smut linked marker RM336 and RM218 were found to be the most informative marker with high Polymorphism Information Content (0.71, 0.69) and Heterozygosity Index (0.76, 0.73). The resistant genotypes such as IG71, Thulasi vasanai sambha, Arupatham vellai, Kaltikar and Chinna aduku nel can be used in the future breeding programmes to develop the resistant cultivar and to identify the candidate genes governing resistance.

Identification and confirmation of powdery mildew (Erysiphe polygoni) resistance in pea germplasm

Erysiphe polygoni DC, the causative agent of powdery mildew, poses a significant threat to pea crop, resulting in substantial yield and economic losses. To address this menace, an exploration of intrinsic resistance within pea germplasm becomes imperative for effective disease management. In our study, phenotyping of 1095 pea accessions, sourced from both indigenous and exotic origins, under natural epiphytotic conditions during Rabi 2021-22, revealed a prevailing susceptibility, with over 60 per cent disease severity in majority of accessions. Remarkably, only 22 accessions, including IC208327, IC220109, IC220378, IC258401, IC262762, IC262849, IC267140, IC267174, IC267727, IC274039, IC274040, IC310074, IC311066, IC345548, IC424898, IC552779, IC613133, IC629544, IC629687, NC57793, IC220193 and EC598669, exhibited resistance with a disease score of <1. Subsequent, pot screening of these 22 resistant accessions under artificial epiphytotic conditions during Rabi 2022-23 confirmed their resistance showing disease severity ranging from 5.83 - 17.50 per cent. Recognizing the pivotal role of resistant varieties in disease management, these identified accessions hold immense potential as resistant donors in crop improvement programs.. KEYWORDS :Germplasm, pea, powdery mildew, resistance

Dual transcriptomic analysis reveals early induced Castanea defense-related genes and Phytophthora cinnamomi effectors.

Phytophthora cinnamomi Rands devastates forest species worldwide, causing significant ecological and economic impacts. The European chestnut (Castanea sativa) is susceptible to this hemibiotrophic oomycete, whereas the Asian chestnuts (Castanea crenata and Castanea mollissima) are resistant and have been successfully used as resistance donors in breeding programs. The molecular mechanisms underlying the different disease outcomes among chestnut species are a key foundation for developing science-based control strategies. However, these are still poorly understood. Dual RNA sequencing was performed in C. sativa and C. crenata roots inoculated with P. cinnamomi. The studied time points represent the pathogen's hemibiotrophic lifestyle previously described at the cellular level. Phytophthora cinnamomi expressed several genes related to pathogenicity in both chestnut species, such as cell wall-degrading enzymes, host nutrient uptake transporters, and effectors. However, the expression of effectors related to the modulation of host programmed cell death (elicitins and NLPs) and sporulation-related genes was higher in the susceptible chestnut. After pathogen inoculation, 1,556 and 488 genes were differentially expressed by C. crenata and C. sativa, respectively. The most significant transcriptional changes occur at 2 h after inoculation (hai) in C. sativa and 48 hai in C. crenata. Nevertheless, C. crenata induced more defense-related genes, indicating that the resistant response to P. cinnamomi is controlled by multiple loci, including several pattern recognition receptors, genes involved in the phenylpropanoid, salicylic acid and ethylene/jasmonic acid pathways, and antifungal genes. Importantly, these results validate previously observed cellular responses for C. crenata. Collectively, this study provides a comprehensive time-resolved description of the chestnut-P. cinnamomi dynamic, revealing new insights into susceptible and resistant host responses and important pathogen strategies involved in disease development.

Haplotype diversity at nine spot blotch resistance QTL in barley

Spot blotch (SB), caused by Bipolaris sorokiniana is becoming an important barley disease in humid, temperate growing regions, including Uruguay. The narrow genetic base of current donors of resistance and recent changes in pathogen virulence have driven the search for novel sources of resistance. In this study, a diverse collection of 39 barley genotypes was evaluated for SB resistance, and genetic relationships, population structure, and haplotype diversity were investigated using 27 simple sequence repeats (SSRs) and eight sequence-tagged sites (STS) markers linked to nine QTL for SB resistance located on chromosomes 1H, 2H, 3H, 4H, and 7H. Fourteen barley genotypes expressed high and moderate SB resistance at seedling and adult plant stages. Distance and model-based cluster analyses revealed that the 14 selected lines clustered in four groups consistent with geographical origin and pedigree relatedness. Reference SB resistant haplotypes were poorly represented. Based on these results, we suggest that these 14 lines are likely candidates to carry novel genes or alleles for SB resistance. Further research may expand the understanding of the genetic architecture of this trait.

Association mapping of tan spot and septoria nodorum blotch resistance in cultivated emmer wheat.

A total of 65 SNPs associated with resistance to tan spot and septoria nodorum blotch were identified in a panel of 180 cultivated emmer accessions through association mapping Tan spot and septoria nodorum blotch (SNB) are foliar diseases caused by the respective fungal pathogens Pyrenophora tritici-repentis and Parastagonospora nodorum that affect global wheat production. To find new sources of resistance, we evaluated a panel of 180 cultivated emmer wheat (Triticum turgidum ssp. dicoccum) accessions for reactions to four P. tritici-repentis isolates Pti2, 86-124, 331-9 and DW5, two P. nodorum isolate, Sn4 and Sn2000, and four necrotrophic effectors (NEs) produced by the pathogens. About 8-36% of the accessions exhibited resistance to the four P. tritici-repentis isolates, with five accessions demonstrating resistance to all isolates. For SNB, 64% accessions showed resistance to Sn4, 43% to Sn2000 and 36% to both isolates, with Spain (11% accessions) as the most common origin of resistance. To understand the genetic basis of resistance, association mapping was performed using SNP (single nucleotide polymorphism) markers generated by genotype-by-sequencing and the 9K SNP Infinium array. A total of 46 SNPs were significantly associated with tan spot and 19 SNPs with SNB resistance or susceptibility. Six trait loci on chromosome arms 1BL, 3BL, 4AL (2), 6BL and 7AL conferred resistance to two or more isolates. Known NE sensitivity genes for disease development were undetected except Snn5 for Sn2000, suggesting novel genetic factors are controlling host-pathogen interaction in cultivated emmer. The emmer accessions with the highest levels of resistance to the six pathogen isolates (e.g., CItr 14133-1, PI 94634-1 and PI 377672) could serve as donors for tan spot and SNB resistance in wheat breeding programs.

Identification of effector genes of <i>Parastagonospora nodorum</i>, <i>P. pseudonodorum</i> in Tambov populations and sensitivity genes to NEs in varieties and hybrid lines of spring soft wheat

BACKGROUND: Parastagonospora nodorum and P. pseudonodorum are known for their ability to produce necrotrophic effectors that play an important role in micromycete pathogenicity. Fungal strains characterized by the presence of effector genes will be used to create artificial infectious backgrounds to identify sources and donors of resistance to fungal diseases. Selected varieties and lines that are donors of recessive alleles snn1 and snn3, which control plant resistance to fungal toxins PtrTox1 and PtrTox3, are recommended for inclusion in programs for breeding wheat for resistance to septoriosis pathogens. AIM: The aim of the work is to assess the populations of the fungi Parastagonospora nodorum and P. pseudonodorum in 2023 based on the presence of effector genes, as well as to identify alleles of Snn1/snn1, Snn3/snn3 genes that control the sensitivity or resistance of wheat to PtrTox1 and PtrTox3 toxins. MATERIALS AND METHODS: Infectious samples were collected in 2023 from spring wheat leaves. In addition, the material for the study was 2 varieties and 23 lines of spring soft wheat of local selection. Using the molecular markers Xfcp624 and Xcfd20, the presence of the Snn1 and Snn3-B1 alleles, which control sensitivity to the fungal toxins PtrTox1 and PtrTox3, was detected. RESULTS: Using molecular screening, ToxA and Tox1 genes were identified in genotypes of P. pseudonodorum isolates; Tox3 and Tox267 in P. nodorum isolates. 2 varieties of spring soft wheat and 11 hybrid lines carry a recessive allele snn1, which protects against the phytopathogen toxin PtrTox1; wheat variety Tambovchanka and 2 hybrid lines carry the recessive allele snn3 on chromosome B1, which confers resistance to the fungal toxin PtrTox3. CONCLUSIONS: The ToxA gene was found only among monoconidial isolates of P. pseudonodorum species obtained from leaves of spring soft wheat of Lebedushka variety. As a result of molecular screening, the Tox1 gene was identified among 70 P. pseudonodorum isolates (43,21% of those studied). The presence of the Tox3 and Tox267 genes was established in 30 isolates of P. nodorum species obtained from plant samples of spring durum wheat Donskaya Elegiya. Using the PCR method, donors of the snn1 and snn3 genes were identified.

Exploring the Resistance of Pigmented Rice to Brown Planthopper (Nilaparvata lugens Stål) by Phenotypic and Genotypic Analyses

Developing new pigmented rice varieties that meet consumers' preferences requires addressing resistance to brown planthopper (BPH), a highly destructive insect pest of rice. To effectively manage this pest, it is essential to explore BPH resistance genes from rice germplasms and incorporate them into elite varieties. The objective of this study was to identify the source of resistance among local and improved pigmented rice varieties in Indonesia against field BPH. Furthermore, the study aimed to characterize their genetic diversity using molecular markers associated with Bph genes and functional markers for these genes. Eighty-eight local varieties from the Indonesian Agricultural Gene Bank, collected across 18 provinces between 1971 and 2019, and four improved varieties, were evaluated using the standard seed box screening test method. Among these entries, 6 local accessions and 1 improved variety exhibited moderate resistance. Genetic analysis of these entries and three randomly selected susceptible entries using 12 SSR and InDel markers associated with Bph gene loci showed that the moderately resistant entries had higher allele numbers (11 to 13) compared to the susceptible entries (4 to 7). These markers could distinguish the resistant group from the susceptible ones in cluster analysis. Genotyping using functional markers further showed that the moderately resistant entries had 2 to 4 combinations of Bph genes. In contrast, the susceptible entries contained neither Bph genes nor only one gene. Local accessions with a 2 to 4 Bph gene combination can be donors of BPH resistance in improving pigmented rice varieties.

Identification and Molecular Validation of Bean Common Mosaic Virus Resistant Donors in Common Bean (Phaseolus vulgaris L.)

Identification and Molecular Validation of Bean Common Mosaic Virus Resistant Donors in Common Bean (Phaseolus vulgaris L.)