Anthracnose Resistance Genes Research Articles

Global transcriptome analysis reveals resistance genes in the early response of common bean (Phaseolus vulgaris L.) to Colletotrichum lindemuthianum

BackgroundDisease can drastically impair common bean (Phaseolus vulgaris L.) production. Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum (Sacc. and Magnus) Briosi and Cavara, is one of the diseases that are widespread and cause serious economic loss in common bean.ResultsTranscriptome analysis of the early response of common bean to anthracnose was performed using two resistant genotypes, Hongyundou and Honghuayundou, and one susceptible genotype, Jingdou. A total of 9,825 differentially expressed genes (DEGs) responding to pathogen infection and anthracnose resistance were identified by differential expression analysis. By using weighted gene coexpression network analysis (WGCNA), 2,051 DEGs were found to be associated with two resistance-related modules. Among them, 463 DEGs related to anthracnose resistance were considered resistance-related candidate genes. Nineteen candidate genes were coexpressed with three resistance genes, Phvul.001G243600, Phvul.001G243700 and Phvul.001G243800. To further identify resistance genes, 46 candidate genes were selected for experimental validation using salicylic acid (SA) and methyl jasmonate (MeJA). The results indicated that 38 candidate genes that responded to SA/MeJA treatment may be involved in anthracnose resistance in common bean.ConclusionsThis study identified 38 resistance-related candidate genes involved in the early response of common bean, and 19 resistance-related candidate genes were coexpressed with anthracnose resistance genes. This study identified putative resistance genes for further resistance genetic investigation and provides an important reference for anthracnose resistance breeding in common bean.

Transcriptome Analysis and Validation of Anthracnose Resistance Genes in Walnut Varieties

Anthracnose is extremely detrimental to walnut production, because it seriously affects its yield. Therefore, this study aimed to identify anthracnose resistance genes in walnuts, to lay the foundation for cultivating novel anthracnose-resistant walnut varieties. In this study, the fruits of walnut varieties “Qinyou 1” and “Qinyou 2”, exhibiting relatively weak resistance to anthracnose, were used for transcriptome sequencing and identifying differentially expressed genes (DEGs). Thereafter, we used a quantitative real-time polymerase chain reaction to verify the reliability of the transcriptome data using the walnut varieties Qinyou 1, Qinyou 2, Qinyou 3, Liaohe 1, and Diamond 1. We identified 6326 DEGs post-infection in Qinyou 1, of which 3065 were upregulated and 3261 were downregulated. We also found 2055 DEGs (969 upregulated and 1086 downregulated genes) in the two varieties, after 6 days of anthracnose infection. Based on GO and KEGG enrichment analyses of the transcriptome data, we noted that the DEGs were primarily involved in metabolic processes, cell composition, cell structure, catalytic activity, and binding activity. Furthermore, KEGG functional enrichment analysis showed that the amino acid biosynthesis pathway and plant–pathogen interaction may be activated under anthracnose infection. We also noted that the expression levels of anthracnose resistance genes in different walnut varieties were significantly different. Thus, the findings of this study provide important genetic resources and molecular markers for the cultivation of novel anthracnose-resistant walnut varieties.

Marker assisted transfer of anthracnose resistance gene Co-5 to elite French bean (Phaseolus vulgaris L.) background

Marker assisted transfer of anthracnose resistance gene Co-5 to elite French bean (Phaseolus vulgaris L.) background

Identification of the allelic state of the Rca2 gene for resistance to anthracnose and determination of genetic relatedness in garden strawberry genotypes

The studies were conducted between 2022-2023. The purpose of the work was to analyze the relationship of hybrids and varieties of strawberries resistant and susceptible to anthracnose and to determine the putative allelic status of the anthracnose resistance gene Rca2. Selection of ISSR primers for identifying polymorphism and constructing dendrites of genetic similarity of 19 garden strawberry genotypes from the collection of the Federal State Budgetary Scientific Institution Federal Scientifi c Center for Horticulture. Th e eff ectiveness of ISSR primers was assessed by the ISSR-PCR method, followed by gel electrophoresis of ISSR-PCR products in an agarose gel. To assess the allelic state of the Rca2 gene, the SCAR marker STS-Rca2_240 was used. The genetic distance of the analyzed strawberry samples was determined using the Jaccard coeffi cient. Cluster analysis was carried out using the STATISTICA program (StatSoft ). The putative allelic status of the anthracnose resistance gene Rca2 in the studied varieties and hybrids was established. Diagnostic fragment of the STS-Rca2_240 marker, 240 bp in size. was found in the Alpha variety. Based on an array of genetic similarity coefficients, dendrograms were constructed, during the analysis of which the relationship of the studied variety samples was established. Promising forms were identifi ed that had a high degree of genetic similarity to varieties resistant to anthracnose, and forms that were closely related to susceptible varieties.

Mapping of adult plant recessive resistance to anthracnose in Indian common bean landrace Baspa/KRC 8.

The common bean (Phaseolus vulgaris) has become the food of choice owing to its wealthy nutritional profile, leading to a considerable increase in its cultivation worldwide. However, anthracnose has been a major impediment to production and productivity, as elite bean cultivars are vulnerable to this disease. To overcome barriers in crop production, scientists worldwide are working towards enhancing the genetic diversity of crops. One way to achieve this is by introducing novel genes from related crops, including landraces like KRC 8. This particular landrace, found in the North Western Himalayan region, has shown adult plant resistance against anthracnose and also possesses a recessive resistance gene. In this study, a population of 179 F2:9 RIL individuals (Jawala ×KRC 8) was evaluated at both phenotypic and genotypic levels using over 830 diverse molecular markers to map the resistance gene present in KRC 8. We have successfully mapped a resistance gene to chromosome Pv01 using four SSR markers, namely IAC 238, IAC 235, IAC 259, and BM 146. The marker IAC 238 is closely linked to the gene with a distance of 0.29cM, while the other markers flank the recessive resistance gene at 10.87cM (IAC 259), 17.80cM (BM 146), and 25.22cM (IAC 235). Previously, a single recessive anthracnose resistance gene (co-8) has been reported in the common bean accession AB 136. However, when we performed PCR amplification with our tightly linked marker IAC 238, we got different amplicons in AB 136 and KRC 8. Interestingly, the susceptible cultivar Jawala produced the same amplicon as AB 136. This observation indicated that the recessive gene present in KRC 8 is different from co-8. As the gene is located far away from the Co-1 locus, we suggest naming the recessive gene co-Indb/co-19. Fine mapping of co-Indb in KRC 8 may provide new insights into the cloning and characterization of this recessive gene so that it can be incorporated into future bean improvement programs. Further, the tightly linked marker IAC 238 can be utilized in marker assisted introgression in future bean breeding programs. The novel co-Indb gene present in Himalayan landrace KRC 8, showing adult plant resistance against common bean anthracnose, is independent from all the resistance genes previously located on chromosome Pv01.

Fine mapping of a new common bean anthracnose resistance gene (Co-18) to the proximal end of Pv10 in Indian landrace KRC-5.

Mapping and fine mapping of bean anthracnose resistance genes is a continuous process. We report fine mapping of anthracnose resistance gene Co-18 which is the first anthracnose gene mapped to Pv10. The discovery of resistance gene is a major gain in the bean anthracnose pathosystem research. Among the Indian common bean landraces, KRC-5 exhibit high levels of resistance to the bean anthracnose pathogen Colletotrichum lindemuthianum. To precisely map the anthracnose resistance gene, we used a Recombinant Inbred Line (F2:9 RIL) population (KRC-5 × Jawala). The inheritance test revealed that KRC-5 carries a dominant resistance gene temporarily designated as Co-18. We discovered two RAPD markers linked to Co-18 among 287 RAPD markers. These RAPD markers were eventually developed into SCARs (Sc-OPR15 and Sc-OPF6) and flank Co-18 on chromosome Pv10 at a distance of 5.3 and 4.2cM, respectively. At 4.0-4.1Mb on Pv10, we detected a SNP (single-nucleotide polymorphism) signal. We synthesized 58 SSRs and 83 InDels from a pool of 135 SSRs and 1134 InDels, respectively. Five SSRs, four InDels, and two SCARs were used to generate the high-density linkage map, which led to the identification of two SSRs (SSR24 and SSR36) that are tightly linked to Co-18. These two SSRs flank the Co-18 to 178kb genomic region with 13 candidate genes including five NLR (nucleotide-binding and leucine-rich repeat) genes. The closely linked markers SSR24 and SSR36 will be used in cloning and pyramiding of the Co-18 gene with other R genes to develop durable resistant bean varieties.

Haplotypes at the sorghum ARG4 and ARG5 NLR loci confer resistance to anthracnose.

Sorghum anthracnose caused by the fungus Colletotrichum sublineola (Cs) is a damaging disease of the crop. Here, we describe the identification of ANTHRACNOSE RESISTANCE GENES (ARG4 and ARG5) encoding canonical nucleotide-binding leucine-rich repeat (NLR) receptors. ARG4 and ARG5 are dominant resistance genes identified in the sorghum lines SAP135 and P9830, respectively, that show broad-spectrum resistance to Cs. Independent genetic studies using populations generated by crossing SAP135 and P9830 with TAM428, fine mapping using molecular markers, comparative genomics and gene expression studies determined that ARG4 and ARG5 are resistance genes against Cs strains. Interestingly, ARG4 and ARG5 are both located within clusters of duplicate NLR genes at linked loci separated by ~1 Mb genomic region. SAP135 and P9830 each carry only one of the ARG genes while having the recessive allele at the second locus. Only two copies of the ARG5 candidate genes were present in the resistant P9830 line while five non-functional copies were identified in the susceptible line. The resistant parents and their recombinant inbred lines carrying either ARG4 or ARG5 are resistant to strains Csgl1 and Csgrg suggesting that these genes have overlapping specificities. The role of ARG4 and ARG5 in resistance was validated through sorghum lines carrying independent recessive alleles that show increased susceptibility. ARG4 and ARG5 are located within complex loci displaying interesting haplotype structures and copy number variation that may have resulted from duplication. Overall, the identification of anthracnose resistance genes with unique haplotype stucture provides a foundation for genetic studies and resistance breeding.

Identification and Characterization of Apple Anthracnose Resistance Genes

Apple is the most widely planted fruit tree in China. Apple anthracnose which caused by the fungus Colletotrichum gloeosporioides is one of the major pathogens causing apple fruit rot and yield loss. In this study, we identified and cloned the Pectinesterase Inhibitor 6-like gene from populations of ‘Fuhan’ and ‘Micui’apples. The Pectinesterase Inhibitor 6-like protein fused to a green fluorescent protein was localized in the cell membrane. The fluorescence quantitative results showed that the expression of Pectinesterase Inhibitor 6-like gene was the highest in sepals and the lowest in styles. The resistant strain was obtained by Agrobacterium-mediated stabilized genetic transformation, and the DNA level identification further proved that the resistant strain was a positive strain successfully transformed.

ANTHRACNOSE RESISTANCE GENE2 confers fungal resistance in sorghum.

Sorghum is an important food and feed crop globally; its production is hampered by anthracnose disease caused by the fungal pathogen Colletotrichum sublineola (Cs). Here, we report identification and characterization of ANTHRACNOSE RESISTANCE GENE 2 (ARG2) encoding a nucleotide-binding leucine-rich repeat (NLR) protein that confers race-specific resistance to Cs strains. ARG2 is one of a cluster of several NLR genes initially identified in the sorghum differential line SC328C that is resistant to some Cs strains. This cluster shows structural and copy number variations in different sorghum genotypes. Different sorghum lines carrying independent ARG2 alleles provided the genetic validation for the identity of the ARG2 gene. ARG2 expression is induced by Cs, and chitin induces ARG2 expression in resistant but not in susceptible lines. ARG2-mediated resistance is accompanied by higher expression of defense and secondary metabolite genes at early stages of infection, and anthocyanin and zeatin metabolisms are upregulated in resistant plants. Interestingly, ARG2 localizes to the plasma membrane when transiently expressed in Nicotiana benthamiana. Importantly, ARG2 plants produced higher shoot dry matter than near-isogenic lines carrying the susceptible allele suggesting an absence of an ARG2 associated growth trade-off. Furthermore, ARG2-mediated resistance is stable at a wide range of temperatures. Our observations open avenues for resistance breeding and for dissecting mechanisms of resistance.

Modified screening method of middle american dry bean genotypes reveals new genomic regions on Pv10 associated with anthracnose resistance.

Anthracnose, caused by the fungal pathogen Colletotrichum lindemuthianum (Sacc. & Magnus) Lams.-Scrib., is one of the most devastating diseases in dry bean (Phaseolus vulgaris L.) with seed yield losses up to 100%. Most anthracnose resistance genes thus far identified behave in a dominant manner and were identified by seedling screening. The Middle American Diversity Panel (MDP; n=266) was screened with a modified greenhouse screening method to evaluate the response to anthracnose race 73. Thirty MDP genotypes exhibited resistance to the race of which 16 genotypes were not known to contain anthracnose resistance genes to race 73. GWAS with ~93,000 SNP markers identified four genomic regions, two each on Pv01 and Pv10, associated race 73 resistance. A likelihood-ratio-based R2 analysis indicated the peak four SNP markers are responsible for 26% of the observed phenotypic variation, where one SNP, S10_072250, explains 23% of the total variation. SNP S10_072250 is associated with a new region of anthracnose resistance and is in an intron of a ZPR1-like gene. Further greenhouse testing of the 16 resistant lines without previously known resistance to race 73 revealed various levels of resistance under various levels of disease pressure. Disease resistance was further characterized in the field using four representative genotypes. GTS-900 and Remington exhibited field resistance while Merlot and Maverick were susceptible. Field testing with two different fungicide regimes revealed the resistant genotypes had no significant disease differences. The results suggest resistance to anthracnose may differ at various growth stages and that breeders have been selecting for major genes at early seedling stages while ignoring the effect of alternative genes that may be active at later stages. The newly identified resistant lines may be related to Age Related Resistance (ARR) and could be exploited as parental sources of anthracnose resistance in addition to already known major genes. The physical localization of the multiple regions of resistance confirms the presence of two clusters of disease resistance genes on Pv01 and identifies two new regions of anthracnose resistance on Pv10 possibly associated with ARR. Future research should look at the mode of inheritance of this resistance and its effect when combined with other anthracnose resistance loci.

Genetic mapping of the Andean anthracnose resistance gene present in the common bean cultivar BRSMG Realce.

The rajado seeded Andean bean (Phaseolus vulgaris L.) cultivar BRSMG Realce (striped seed coat) developed by Embrapa expressed a high level of anthracnose resistance, caused by Colletotrichum lindemuthianum, in field and greenhouse screenings. The main goal of this study was to evaluate the inheritance of anthracnose resistance in BRSMG Realce, map the resistance locus or major gene cluster previously named as Co-Realce, identify resistance-related positional genes, and analyze potential markers linked to the resistance allele. F2 plants derived from the cross BRSMG Realce × BRS FC104 (Mesoamerican) and from the cross BRSMG Realce × BRS Notável (Mesoamerican) were inoculated with the C. lindemuthianum races 475 and 81, respectively. The BRSMG Realce × BRS FC104 F2 population was also genotyped using the DArTseq technology. Crosses between BRSMG Realce and BAT 93 (Mesoamerican) were also conducted and resulting F2 plants were inoculated with the C. lindemuthianum races 65 and 1609, individually. The results shown that anthracnose resistance in BRSMG Realce is controlled by a single locus with complete dominance. A genetic map including 1,118 SNP markers was built and shown 78% of the markers mapped at a distances less than 5.0 cM, with a total genetic length of 4,473.4 cM. A major locus (Co-Realce) explaining 54.6% of the phenotypic variation of symptoms caused by the race 475 was identified in Pv04, flanked by the markers snp1327 and snp12782 and 4.48 cM apart each other. These SNPs are useful for marker-assisted selection, due to an estimated selection efficiency of 99.2%. The identified resistance allele segregates independently of the resistance allele Co-33 (Pv04) present in BAT 93. The mapped genomic region with 704,867 bp comprising 63 putative genes, 44 of which were related to the pathogen-host interaction. Based on all these results and evidence, anthracnose resistance in BRSMG Realce should be considered as monogenic, useful for breeding purpose. It is proposed that locus Co-Realce is unique and be provisionally designated as CoPv04R until be officially nominated in accordance with the rules established by the Bean Improvement Cooperative Genetics Committee.

Introgression of anthracnose resistance Co-4 gene in elite French bean (Phaseolus vulgaris L.) background using linked molecular marker SY20

French bean is one of the most important staple foods in many parts of the world. Among several bacterial, fungal and viral diseases, anthracnose caused by Colletotrichum lindemuthianum is the most widespread and severe disease of French bean. Therefore, the present study was undertaken as prebreeding effort with the objective of introgression of important bean anthracnose resistance gene Co-4 in elite cultivar. Hybridization between resistant genotype, TO having bean anthracnose resistance gene Co-4 and elite cultivar Arka Komal was done. Cross Arka Komal × TO was further advanced to generate, F1, BC1F1, BC2F1 and BC2F2 plants. Testing of hybridity of the resultant F1, BC1F1, BC2F1 and BC2F2 plants/pods using gene linked SCAR marker SY20 resulted in identification of 46 gene-positive BC2F2. Further foreground selection revealed lack of segregation for the target gene Co-4 in 16 progenies. Screening of these 16 homozygous progenies (Co-4 gene) following detached pod and germinated seed dip methods using race 3 of C. lindemuthianum validated Co-4 imparted resistance in all the 16 BC2F3 progenies. Agronomic evaluation of 16 Co-4 gene-positive BC2F4 progenies for 8 qualitative traits and 9 quantitative traits led to identification of AKTO 4, AKTO 5, AKTO 7 and AKTO 43 progenies as having better elite background. These can either be used as donors of resistance gene for further introgression and gene pyramiding or can further be advanced following backcrossing to develop essentially derived variety of elite parent, Arka Komal.

Introgression of anthracnose resistance gene(s) into common bean (Phaseolus vulgaris)

Abstract. Kazimoto GK, Nchimbi-Msolla SF, Mabagala RB. 2022. Introgression of anthracnose resistance gene(s) into common bean (Phaseolus vulgaris). Cell Biol Dev 6: 20-31. Common bean anthracnose disease caused by the fungus Colletotrichum lindemuthianum causes significant yield losses. It is most destructive in areas with cool temperatures and high humidity (90-100%). The study aimed to introduce resistance genes into adapted but susceptible local cultivars of Masai Red and Soya Njano using conventional breeding methods. Five races of C. lindemuthianum were isolated and named from thirty-two common bean-diseased plant samples collected from Northern Tanzania. The sources of resistant genes were bean cultivars G2333 and AB136. Early developed populations were evaluated under field conditions in high altitude and humid environments at Bashnet in the Manyara region, in the Northern highlands of Tanzania. Both F2 and F3 populations of Soya Njano x G2333 were segregated for C. lindemuthianum resistance at a 9:7 ratio. Such segregation implied that two dominant epistatic genes conferred from G2333, the resistance being in the mode of epistatic gene interaction. The crosses between Masai Red x G2333 and F2 and F3 populations segregation ratio was 10:6, implying two dominant resistant genes were transferred to developed populations. The F2 and F3 progenies obtained from crossing Soya Njano and AB136 showed a ratio of 3:1. The F2 progenies from a cross between Masai Red and AB136 were segregated at a ratio of 3:1 and F3 progenies were 3:1. The 3:1 ratio confirmed single dominant gene inheritance conferred to developed progenies. The heritability (h²) from populations of Soya Njano x G2333 and Masai Red x G2333 was between 0.41 and 0.45. While Soya Njano, Masai Red, and A136 were between 0.2 and 0.53, which implied moderate heritability. F2 and F3 populations developed need further testing using MAS to confirm the presence of resistant genes. Multi-location testing should be done to verify the resistance levels of the developed bean population in later generations.

Phaseolus vulgaris-Colletotrichum lindemuthianum Pathosystem in the Post-Genomic Era: An Update.

Phaseolus vulgaris-Colletotrichum lindemuthianum is one among the oldest host and pathogen interface. Researchers have taken painstaking efforts across the world for understanding the dialogue during early and late phases of interaction. Collectively, these efforts resulted in the deluge of information that helped the researchers to underpin the interface. The latest molecular biology techniques furnished novel detection methods for the anthracnose pathogen, refined the understanding of pathogen population dynamics, and provided the insights on co-evolutionary common bean resistance and C. lindemuthianum virulence dynamics. One of the important breakthroughs came when the Phaseolus vulgaris and its corresponding anthracnose pathogen (C. lindemuthianum) genomes were decoded in 2014 and 2017, respectively. Availability of both the genomes yielded a significant genomic information that helped bean communities to fine map the economically important traits and to identify the pathogenicity determinants and effector molecules. The interface is in a continuous development as knowledge of the anthracnose resistance genes, their precise physical locations, and the identification of effector proteins; the fungus arsenals are being routinely updated. Hence, we revisited the interface and tried to provide an overview of host pathogen dialogue in the genomic era. Additionally, we compiled the sporadic information on this pathosystem from India and provided its futuristic road map to shape its research in the world and northern India, the major dry bean area in the country.

Screening of common bean (Phaseolus vulgaris L.) germplasm against Colletotrichum lindemuthianum inciting bean anthracnose

Common bean is the most cultivated grain legume consumed globally. It is enriched in proteins, vitamins, minerals and fiber. Anthracnose disease incited by hemibiotrophic fungi Colletotrichum lindemuthianum is the most destructive disease of common beans. The present study was carried out to evaluate 87 common bean genotypes collected from different locations against C. lindemuthianum. Screening of genotypes for anthracnose resistance aids in the identification of 22 highly resistant genotypes namely PL 1, EC-400397, Hur 137, IC-199277, IC-258273, S 2, EC-400442, KB 4, Utkarsh, Hur 15, IC-260299, PDR 14, VL 125, Amber, Arun, EC-398591, EC-121013, S 6, BR 31, IC- 328372, KB 12 and KB 6. These genotypes can act as potential donors of the resistant genes in markerassisted selection (MAS) programmes for transferring the anthracnose resistance gene(s) into the susceptible genotypes.

Genome-wide association analysis of anthracnose resistance in sorghum [Sorghum bicolor (L.) Moench

In warm-humid ago-ecologies of the world, sorghum [Sorghum bicolor (L.) Moench] production is severely affected by anthracnose disease caused by Colletotrichum sublineolum Henn. New sources of anthracnose resistance should be identified to introgress novel genes into susceptible varieties in resistance breeding programs. The objective of this study was to determine genome-wide association of Diversity Arrays Technology Sequencing (DArTseq) based single nucleotide polymorphisms (SNP) markers and anthracnose resistance genes in diverse sorghum populations for resistance breeding. Three hundred sixty-six sorghum populations were assessed for anthracnose resistance in three seasons in western Ethiopia using artificial inoculation. Data on anthracnose severity and the relative area under the disease progress curve were computed. Furthermore, the test populations were genotyped using SNP markers with DArTseq protocol. Population structure analysis and genome-wide association mapping were undertaken based on 11,643 SNPs with <10% missing data. The evaluated population was grouped into eight distinct genetic clusters. A total of eight significant (P < 0.001) marker-trait associations (MTAs) were detected, explaining 4.86-15.9% of the phenotypic variation for anthracnose resistance. Out of which the four markers were above the cutoff point. The significant MTAs in the assessed sorghum population are useful for marker-assisted selection (MAS) in anthracnose resistance breeding programs and for gene and quantitative trait loci (QTL) mapping.

Occurrence of anthracnose pathogen races and resistance genes in common bean across 30 years in Brazil

Anthracnose caused by Colletotrichum lindemuthianum is one of the most critical diseases in the common bean (Phaseolus vulgaris L.). The characterization and localization of pathogenic fungal races are essential for understanding pathogen population dynamics and recommending strategies to develop resistant cultivars. As resistant genotypes are the most economical and ecologically safe means of controlling plant diseases, there have been efforts to characterize resistance genes in common bean. Several studies using a system of 12 differential bean cultivars have been carried out to monitor anthracnose since 1991, reporting the constant appearance of new fungal races. C. lindemuthianum shows high virulence diversity. The objective of the present study was to review the relationship between C. lindemuthianum races and the common bean pathogenic processes involved in the risk of developing anthracnose disease. As a result, 89 races occurred in Brazil, wherein 73, 65, and 81 of C. lindemuthianum are the most frequent. Furthermore, we built a map with the anthracnose resistance loci, molecular markers, and their respective physical position. The accessibility to the genomes and sequencing technologies permits molecular markers for marker-assisted selection applied to anthracnose-resistant cultivars. This study could be used as a reference for future resistance mapping studies and as a guide for selecting resistance loci in breeding programs aiming to develop common bean cultivars with durable anthracnose resistance.

Resistance sources and reactions of common bean (Phaseolus vulgaris L.) cultivars in Turkey to anthracnose disease

Anthracnose caused by Colletotrichum lindemuthianum is one of the major diseases of common bean (Phaseolus vulgaris L.) worldwide. The aim of this study was to analyze common bean cultivars in Turkey for Co resistance genes using different molecular markers (SC08, SBB14, OPAZ04, SF10, OPF10, OPA18, SB12, TGA1, SAB3, SCAreoli, SZ04, and OPV20) linked with anthracnose resistance genes and evaluate the reaction of these cultivars to the pathogen isolates. The results showed the presence of Co-1, Co-14, Co-15, Co-2, Co-4, Co-42, Co-6, Co-10, Co-11, and Co-13 resistance genes, alone or combination except for Co-33 and Co-5, in common bean cultivars. These cultivars carried predominantly Co-6 and Co-4 genes for anthracnose resistance. Five cultivar (Sazova, Zulbiye, Akin, Onceler and Karacasehir 90), carrying Co-1, Co-14, Co-15, Co-2, Co-10, Co-13, Co-4, and Co-6 resistance genes were resistant to the pathogen isolates. These cultivars, showing a high level of resistance to the pathogen can be used as resistance sources in common bean breeding programs for resistance to anthracnose disease. These markers will provide significant benefit in breeding strategies.

Assessment of strawberry varieties by anthracnose resistance gene

The results of marker-assisted identification of the Rca2 anthracnose resistance gene in promising strawberry varieties were shown. The DNA marker STS-Rca2_240, linked to the Rca2 anthracnose resistance allele was identified in varieties Albion and Aprica (F. × ananassa), and variety Dar (F. × anashata). Strawberry varieties Alpha, Bereginya, Kokinskaya Zarya, Pamyati Zubova, Rubinovy kaskad, Slavutich, Yuniol, Big King, Brilla, Joly, Rumba and Vivara are characterized by the absence of the marker STS-Rca2_240. In strawberry varieties with the identified marker STS-Rca2_240 (Dar, Albion and Aprica), the Rca2 gene can be in a dominant homozygous or heterozygous state, which makes it possible to recommend these genotypes for use in breeding for anthracnose resistance.

Molecular Marker-Assisted Backcrossing of Anthracnose Resistance Genes into Common Beans (&amp;lt;i&amp;gt;Phaseolus vulgaris&amp;lt;/i&amp;gt; L.) Varieties

Anthracnose, caused by Colletotrichum lindemuthianum, is a major disease of common bean and results in high yield loss. Due to the high degree of pathogenic variability of the fungus and the continual emergence of new races, genetic resistance in the host is not durable. Gene pyramiding using Marker Assisted Selection (MAS) is proposed as a viable approach to improve the durability of major genes conditioning resistance to anthracnose. In this study a common bean line Urugezi x AND 1062 susceptible to anthracnose but already improved for Pythium root rot resistance was improved for anthracnose resistance through a backcross breeding program. Genotypic selection was done in Rubilizi laboratory in Kigali, Rwanada whereas phenotypic selection was conducted in an anthracnose hotspot at Rwerere, a research Centre of the Rwanda Agricultural and Animal Resources Development Board (RAB). Analysis of variance for effect of bean varieties and anthracnose isolates on disease expression showed significant differences (p 2F1 plants were 41% of them resistant and 59% susceptible to anthracnose. However, the observed proportion of 26 resistants and 37 susceptible in BC2F1 plants didn’t fit the goodness of fit of the expected proportion of 75 resistants to 25 susceptible. Only 41% of BC2F1 plants inherited the resistance genes and were phenotypically resistant. Presence of SCAR-markers, SAB3 and SBB14, in the developed resistant lines h suggested successful resistance transfer of anthracnose resistance genes.