scholarly journals Marker-assisted pyramiding of two major broad-spectrum bacterial blight resistance genes,Xa21andXa33into an elite maintainer line of rice, DRR17B

2018 ◽  
Author(s):  
CH Balachiranjeevi ◽  
S Bhaskar Naik ◽  
V Abhilash Kumar ◽  
G Harika ◽  
H.K Mahadev Swamy ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Bacterial Blight ◽  
Durable Resistance ◽  
Gene Pyramiding ◽  
Resistance Breeding ◽  
Fertility Restorer ◽  
Rice Varieties ◽  
Homozygous Condition ◽  
Specific Pcr ◽  
High Level

AbstractBacterial blight (BB) disease reduces the yield of rice varieties and hybrids considerably in many tropical rice growing countries like India. The present study highlights the development of durable BB resistance into the background of an elite maintainer of rice, DRR17B, by incorporating two major dominant genes,Xa21andXa33through marker-assisted backcross breeding (MABB). Through two sets of backcrosses, the two BB resistance genes were transferred separately to DRR17B. In this process, at each stage of backcrossing, foreground selection was carried out for the target resistance genes and for non-fertility restorer alleles concerning the major fertility restorer genesRf3andRf4, using gene-specific PCR-based markers, while background selection was done using a set of 61 and 64 parental polymorphic SSR markers respectively. Backcross derived lines possessing eitherXa21orXa33along with maximum genome recovery of DRR17B were identified at BC3F1generation and selfed to develop BC3F2s. Plants harboringXa21orXa33in homozygous condition were identified among BC3F2s and were intercrossed with each other to combine both the genes. The intercross F1plants (ICF1) were selfed and the intercross F2(ICF2) plants possessing bothXa21andXa33in homozygous condition were identified with the help of markers. They were then advanced further by selfing until ICF4generation. Selected ICF4lines were evaluated for their resistance against BB with eight virulent isolates and for key agro-morphological traits. Six promising two-gene pyramiding lines of DRR17B with high level of BB resistance and agro-morphological attributes similar or superior to DRR17B with complete maintenance ability have been identified. These lines with elevated level of durable resistance may be handy tool for BB resistance breeding.

scholarly journals Gene Pyramiding for Achieving Enhanced Resistance to Bacterial Blight, Blast, and Sheath Blight Diseases in Rice

2020 ◽  
Vol 11 ◽  
Author(s):  
Jegadeesan Ramalingam ◽  
Chandavarapu Raveendra ◽  
Palanisamy Savitha ◽  
Venugopal Vidya ◽  
Thammannagowda Lingapatna Chaithra ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Bacterial Blight ◽  
Durable Resistance ◽  
Gene Pyramiding ◽  
Resistance Breeding ◽  
Sheath Blight ◽  
Potential Donor ◽  
Broad Spectrum Resistance ◽  
Combine Blast ◽  
High Degree

Bacterial blight, blast, and sheath blight are the commonest diseases causing substantial yield loss in rice around the world. Stacking of broad-spectrum resistance genes/QTLs into popular cultivars is becoming a major objective of any disease resistance breeding program. The varieties ASD 16 and ADT 43 are the two popular, high yielding, and widely grown rice cultivars of South India, which are susceptible to bacterial blight (BB), blast, and sheath blight diseases. The present study was carried out to improve the cultivars (ASD 16 and ADT 43) through introgression of bacterial blight (xa5, xa13, and Xa21), blast (Pi54), and sheath blight (qSBR7-1, qSBR11-1, and qSBR11-2) resistance genes/QTLs by MABB (marker-assisted backcross breeding). IRBB60 (xa5, xa13, and Xa21) and Tetep (Pi54; qSBR7-1, qSBR11-1, and qSBR11-2) were used as donors to introgress BB, blast, and sheath blight resistance into the recurrent parents (ASD 16 and ADT 43). Homozygous (BC3F3 generation), three-gene bacterial blight pyramided (xa5 + xa13 + Xa21) lines were developed, and these lines were crossed with Tetep to combine blast (Pi54) and sheath blight (qSBR7-1, qSBR11-1, and qSBR11-2) resistance. In BC3F3 generation, the improved pyramided lines carrying a total of seven genes/QTLs (xa5 + xa13 + Xa21 + Pi54 + qSBR7-1 + qSBR11-1 + qSBR11-2) were selected through molecular and phenotypic assay, and these were evaluated for resistance against bacterial blight, blast, and sheath blight pathogens under greenhouse conditions. We have selected nine lines in ASD 16 background and 15 lines in ADT 43 background, exhibiting a high degree of resistance to BB, blast, and sheath blight diseases and also possessing phenotypes of recurrent parents. The improved pyramided lines are expected to be used as improved varieties or used as a potential donor in breeding programs. The present study successfully introgressed Pi54, and qSBR QTLs (qSBR7-1, qSBR11-1, and qSBR11-2) from Tetep and major effective BB-resistant genes (xa5, xa13, and Xa21) from IRBB60 into the commercial varieties for durable resistance to multiple diseases.

scholarly journals A Comprehensive Review of the Major Genes Conditioning Resistance to Anthracnose in Common Bean

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1196-1207 ◽  
Author(s):  
James D. Kelly ◽  
Veronica A. Vallejo
Keyword(s):  
Common Bean ◽  
Resistance Genes ◽  
Durable Resistance ◽  
Gene Pyramiding ◽  
Resistance Breeding ◽  
Gene Clusters ◽  
Allelic Series ◽  
Multiple Alleles ◽  
Differential Cultivars ◽  
Major Resistance Genes

Resistance to anthracnose in common bean is conditioned primarily by nine major independent genes, Co-1 to Co-10 as the Co-3/Co-9 genes are allelic. With the exception of the recessive co-8 gene, all other nine are dominant genes and multiple alleles exist at the Co-1, Co-3 and Co-4 loci. A reverse of dominance at the Co-1 locus suggests that an order of dominance exists among individual alleles at this locus. The nine resistance genes Co-2 to Co-10 are Middle American in origin and Co-1 is the only locus from the Andean gene pool. Seven resistance loci have been mapped to the integrated bean linkage map and Co-1 resides on linkage group B1; Co-2 on B11, Co-3 on B4; Co-4 on B8; Co-6 on B7; and Co-9 and Co-10 are located on B4 but do not appear to be linked. Three Co-genes map to linkage groups B1, B4 and B11 where clusters with genes for rust resistance are located. In addition, there is co-localization with major resistance genes and QTL that condition partial resistance to anthracnose. Other QTL for resistance may provide putative map locations for the major resistance loci still to be mapped. Molecular markers linked to the majority of major Co-genes have been reported and these provide the opportunity to enhance disease resistance through marker-assisted selection and gene pyramiding. The 10 Co-genes are represented in the anthracnose differential cultivars, but are present as part of a multi-allelic series or in combination with other Co-genes, making the characterization of more complex races difficult. Although the Co-genes behave as major Mendelian factors, they most likely exist as resistance gene clusters as has been demonstrated on the molecular level at the Co-2 locus. Since the genes differ in their effectiveness in controlling the highly variable races of the anthracnose pathogen, the authors discuss the value of individual genes and alleles in resistance breeding and suggest the most effective gene pyramids to ensure long-term durable resistance to anthracnose in common bean.

scholarly journals Two novel gene-specific markers at pik locus facilitate the application of rice blast resistant alleles in breeding

2019 ◽  
Author(s):  
Dagang Tian ◽  
Ziqiang Chen ◽  
Yan Lin ◽  
Zaijie Chen ◽  
Jiami Luo ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Rice Blast ◽  
Blast Resistance ◽  
Durable Resistance ◽  
Resistance Breeding ◽  
Blast Disease ◽  
Chromosome 11 ◽  
Rice Varieties ◽  
Breeding Programs ◽  
New Gene

Abstract Background: Rice blast disease, caused by Magnaporthe oryzae, is a major constraint for rice production in the world. Introgression of blast-durable resistance genes into high-yielding rice cultivars has been considered an agricultural priority in an effort to control the disease. The blast resistance Pik locus, located on chromosome 11, contains at least six important resistance genes, but these genes have not been widely employed in resistance breeding since existing markers hardly satisfy current breeding needs owing to their limited scope of application.Results: In the present study, two PCR-based markers, Pikp-Del and Pi1-In, were developed to target the specific InDel (insertion/deletion) of the Pik-p and Pi-1 genes, respectively. The two markers precisely distinguished Pik-p, Pi-1, and the K-type alleles at the Pik locus, which is a necessary element for functional genes from rice varieties. Conclusions:Two gene-specific markers of Pi-kp and Pi1 identified that only several old varieties contain the two genes, nearly half these varieties yet carry the K-type alleles. Therefore, these identified varieties can be new gene sources for developing blast resistant rice. The two newly developed markers should be highly useful for using Pi-kp, Pi1 and other resistance genes at the Pik locus in marker-assisted selection (MAS) breeding programs.

scholarly journals Soybean cyst nematodes: a destructive threat to soybean production in China

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Deliang Peng ◽  
Ru Jiang ◽  
Huan Peng ◽  
Shiming Liu
Keyword(s):  
Resistance Genes ◽  
Soybean Cyst Nematode ◽  
Integrated Management ◽  
Resistance Breeding ◽  
Research Progress ◽  
Cyst Nematodes ◽  
Soybean Production ◽  
Specific Pcr ◽  
Soybean Cyst Nematodes ◽  
Soybean Resistance

AbstractSoybean cyst nematode (SCN), Heterodera glycines, is one of the most important pests in soybean production worldwide. In China, 11 different races of SCN, including a newly identified race ‘X12’ with super-virulence, have been surveyed and found to be distributed in 22 provinces. Among them, races 1, 3 and 4 are dominant in the two principal soybean-producing areas, Northeast China and Huanghuaihai Valley, causing over 120 million dollars of annual yield loss. Rapid and reliable PCR-based approaches have been developed for the molecular diagnosis of SCN. High-throughput methods for the identification of soybean resistance against SCN are also developed with specific single nucleotide polymorphism markers by using Kompetitive Allele Specific PCR technology. Over 10,000 soybean germplasm sources were evaluated for their SCN resistance, and 28 SCN-resistant soybean accessions were selected to construct an applied core collection, which has been used for soybean breeding in China. Recently, the genome sequences of SCN and soybean are publically available, and two major SCN-resistant genes (rhg1 and Rhg4) have been identified in soybean, which greatly facilitate the researches on SCN virulence and soybean resistance, and also soybean resistance breeding against SCN. However, the management of SCN still faces many bottlenecks, for instance, the single resistance genes in soybean cultivars can be easily overcome by new SCN races; the identified resistance genes are inadequate to meet the practical breeding needs; and our understanding of the mechanisms of SCN virulence and soybean resistance to SCN are limited. SCN is a destructive threat to soybean production throughout the world including China. In this review, the major progress on soybean SCN is summarized, mainly focusing on the recent research progress in SCN, soybean resistance to SCN and integrated management of SCN in China, and aiming at a better understanding of the current SCN research status and prospects for future work.

scholarly journals Race structure of cowpea witchweed (Striga gesnerioides) in West Africa and its implications for Striga resistance breeding of cowpea

Weed Science ◽  
2020 ◽  
Vol 68 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Erik W. Ohlson ◽  
Michael P. Timko
Keyword(s):  
West Africa ◽  
Resistance Genes ◽  
Broad Spectrum ◽  
Genetic Relatedness ◽  
Durable Resistance ◽  
Resistance Breeding ◽  
Differential Resistance ◽  
African Countries ◽  
Sources Of Resistance ◽  
Striga Gesnerioides

AbstractCowpea witchweed [Striga gesnerioides (Willd.) Vatke] is a primary constraint of cowpea [Vigna unguiculata (L.) Walp.] production in West Africa. Previously, seven S. gesnerioides races were classified based upon host specificity and genotypic profiling. Because race number and distribution are dynamic systems influenced by gene flow, genetic drift, and natural selection, a thorough investigation of S. gesnerioides diversity and the effectiveness of known sources of resistance in cowpea is needed to develop varieties with durable and broad-spectrum Striga resistance. In this study, we screened seven cowpea lines against 58 unique S. gesnerioides populations collected from across nine West African countries. Individuals from 10 S. gesnerioides populations were genotyped with simple sequence repeat (SSR) markers. We identified six races of S. gesnerioides based on their parasitism of the seven cowpea lines with known differential resistance genotypes. No cowpea line was resistant to all 58 Striga populations and none of the Striga populations were able to overcome the resistance of all seven lines. A novel race, SG6, of the parasite collected from Kudu, Nigeria, was found to overcome more cowpea resistance genes than any previously reported race. SSR analysis indicates that Striga populations are highly differentiated and genetic relatedness generally corresponds with geographic proximity rather than their host compatibility. Due to the dearth of broad-spectrum resistance found among Striga-resistant cowpea lines, there exists a need to stack multiple Striga resistance genes in order to confer broad-spectrum and durable resistance.

scholarly journals Recent Strategies for Detection and Improvement of Brown Planthopper Resistance Genes in Rice: A Review

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1202
Author(s):  
Bello Sani Haliru ◽  
Mohd Y. Rafii ◽  
Norida Mazlan ◽  
Shairul Izan Ramlee ◽  
Isma’ila Muhammad ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Large Scale ◽  
Insect Pest ◽  
Durable Resistance ◽  
Brown Planthopper ◽  
Gene Clusters ◽  
Nilaparvata Lugens ◽  
Scale Production ◽  
Rice Varieties ◽  
Resistant Genes

Brown planthopper (BPH; Nilaparvata lugens Stal) is considered the main rice insect pest in Asia. Several BPH-resistant varieties of rice have been bred previously and released for large-scale production in various rice-growing regions. However, the frequent surfacing of new BPH biotypes necessitates the evolution of new rice varieties that have a wide genetic base to overcome BPH attacks. Nowadays, with the introduction of molecular approaches in varietal development, it is possible to combine multiple genes from diverse sources into a single genetic background for durable resistance. At present, above 37 BPH-resistant genes/polygenes have been detected from wild species and indica varieties, which are situated on chromosomes 1, 3, 4, 6, 7, 8, 9, 10, 11 and 12. Five BPH gene clusters have been identified from chromosomes 3, 4, 6, and 12. In addition, eight BPH-resistant genes have been successfully cloned. It is hoped that many more resistance genes will be explored through screening of additional domesticated and undomesticated species in due course.

scholarly journals Identification of novel rice blast resistance alleles through sequence-based allele mining

2019 ◽  
Author(s):  
Ying Zhou ◽  
Fang Lei ◽  
Qiong Wang ◽  
Weicong He ◽  
Yuan Bin ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Rice Blast ◽  
Blast Resistance ◽  
Resistance Breeding ◽  
Economic Losses ◽  
The Novel ◽  
Allele Mining ◽  
Rice Varieties ◽  
Rice Blast Resistance ◽  
Blast Resistance Genes

Abstract Background: As rice ( Oryza sativa ) is the staple food of more than half the world’s population, rice production contributes greatly to global food security. Rice blast caused by the fungus M agnaporthe oryzae is a devastating fungal disease of rice, affecting yield and grain quality and resulting in substantial annual economic losses. Because the fungus evolves rapidly,, resistance conferred by most of the single blast race resistance genes is often broken after a few years of intensive agricultural use. Effective resistance breeding in rice therefore requires continual enrichment of the reservoir of resistance genes and alleles. Seed banks represent a rich source of genetic diversity; however, they have not been extensively used to identify novel genes and alleles. Results: We carried out a large-scale screen for novel blast resistance alleles in 1883 rice varieties from major rice producing areas across China. Of these, 107 varieties showed at least moderate resistance to natural infection by rice blast at rice blast nurseries in Enshi and Yichang, Hubei Province. Using sequence-based allele mining to amplify and clone the allelic variants of major rice blast resistance genes at the Pi2/9/gm/zt locus of chromosome 6 from the 107 blast-resistant varieties, we identified 13 novel blast resistance alleles. We then used controlled infections to assess the resistance of rice varieties carrying the novel alleles to 34 single rice blast isolates from Hubei, Guangdong, Jiangsu, Hunan, Jangxi, Sichuan, Heilongjiang, and Fujin Provinces. The varieties identified as being resistant in the nursery trials showed varied disease responses when infected with the single blast isolates, suggesting that the novel Pi2/9/gm/zt alleles vary in their blast resistance spectra. Some of the newly identified alleles have unique single nucleotide polymorphisms (SNPs), insertions, or deletions, in addition to polymorphic residues that are shared between the different alleles. Conclusions: These alleles expand the allelic series of blast resistance genes, enriching the genetic resource for rice blast resistance breeding programs and for studies aimed at deciphering rice–rice blast molecular interactions. Key words : Pi9 , R-genes, Nucleotide diversity, Gene conversion, Resistance gene alleles, Rice blast

scholarly journals Improvement of bacterial blight resistance of the popular variety, Nellore Mahsuri, NLR34449 through marker-assisted breeding

2020 ◽  
Author(s):  
Aleena D ◽  
Padma V ◽  
Rekha G ◽  
Dilip T ◽  
Punniakotti E ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Bacterial Blight ◽  
Grain Quality ◽  
Rice Variety ◽  
Blight Resistance ◽  
Bacterial Blight Resistance ◽  
Marker Assisted Breeding ◽  
Fine Grain ◽  
High Level ◽  
Marker Assisted Backcross Breeding

Abstract To combat the dreaded diseases in rice like bacterial blight and blast, host plant resistance has been advocated as a sustainable method. Through the present study, we have successfully incorporated three major bacterial blight (BB) resistance genes viz., Xa21, xa13 and xa5 into NLR3449, a high yielding, blast resistant, fine-grain type popular rice variety through marker-assisted backcross breeding. Foreground selection was carried out using PCR based, gene-specific markers viz., pTA248 (Xa21), xa13prom (xa13) and xa5FM (xa5) at each generation of backcrossing, while 127 polymorphic SSR markers spanning on 12 chromosomes were used for background selection and backcrossing was limited to two rounds. At BC2F1 generation, a single plant (NLR-87-10) with 89.9% recovery and possessing all the three bacterial blight resistance genes was forwarded to BC2F2 generation. A solitary BC2F2 plant viz., NLR-87-10-106 possessing all the three resistance genes and > 90% genome recovery was identified and advanced through selfing till BC2F4 generation by adopting pedigree method. Three best lines at BC2F4 lines, possessing high level of resistance against bacterial blight and blast and equivalent or superior to NLR 34449 in terms of yield, grain quality and agro-morphological traits have been identified and advanced for multi-location trials.

scholarly journals Rice Blast Disease in India: Present Status and Future Challenges

2021 ◽  
Author(s):  
Deepak Chikkaballi Annegowda ◽  
Mothukapalli Krishnareddy Prasannakumar ◽  
Hirehally Basavarajegowda Mahesh ◽  
Chethana Bangera Siddabasappa ◽  
Pramesh Devanna ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Oryza Sativa L ◽  
Blast Resistance ◽  
Gene Pyramiding ◽  
Climatic Conditions ◽  
Blast Disease ◽  
Selection Marker ◽  
Rice Varieties ◽  
Future Challenges ◽  
Blast Resistance Genes

Rice (Oryza sativa L.) is the staple food of the majority of Indians, and India is both the major producer and consumer of rice. Rice cultivation in India is confronted with diverse agro-climatic conditions, varying soil types, and several biotic and abiotic constraints. Among major fungal diseases of Rice in India, the blast caused by Magnaporthe oryzae is the most devastating disease, with the neck blast being the most destructive form. Most of the blast epidemic areas in India have been identified with a mixture of races blast fungus resulting in the resistance breakdown in a short period. At present, a more significant number of the rice varieties cultivated in India were bred by conventional breeding methods with blast resistance conferred by a single resistance gene. Therefore, the blast disease in India is predominantly addressed by the use of ecologically toxic fungicides. In line with the rest of the world, the Indian scientific community has proven its role by identifying several blast resistance genes and successfully pyramiding multiple blast resistance genes. Despite the wealth of information on resistance genes and the availability of biotechnology tools, not a great number of rice varieties in India harbor multiple resistance genes. In the recent past, a shift in the management of blast disease in India has been witnessed with a greater focus on basic research and modern breeding tools such as marker-assisted selection, marker-assisted backcross breeding, and gene pyramiding.

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