Plant disease resistance

About: Plant disease resistance is a research topic. Over the lifetime, 12952 publications have been published within this topic receiving 381820 citations. The topic is also known as: plant innate immunity.

Poplar and pathogen interactions: insights from Populus genome-wide analyses of resistance and defense gene families and gene expression profiling.

Abstract: Our understanding of the molecular basis of plant-pathogen interactions is derived mostly from studies of model annual plant species, and until recently, few addressed disease resistance and defense responses in long-lived species such as trees. The release of the Populus genome sequence has permitted extensive genome-wide surveys of gene families and comparative analyses of other sequenced plant genomes. These have revealed striking features for gene families that play key roles in the plant defense response. For example, the NBS-LRR resistance ( R )-gene family is expanded compared with other plant genomes, including R -gene subfamilies not previously reported in plants. Some of these genes are clustered on the subtelomeric part of a chromosome that shows segregation distortion in genetic studies. Similar expansion is observed for other genes playing key roles in plant defense such as pathogenesis-related proteins. Among the many pathogens that infect poplar trees, Melampsora spp. fungi, which cause rus...

Alternaria Black Spot of Crucifers: Symptoms, Importance of Disease, and Perspectives of Resistance Breeding

Abstract: Summary Alternaria black spot of cruciferous vegetables, incited by different species of Alternaria, remains an increasing threat to Brassicaceae crops throughout the world, including Poland. Brassica plants are attacked by conidia of A. brassicae (Berk.) Sacc., A. brassicicola (Schw.) Wiltsh., A. raphani Groves & Skolko, and A. alternata (Fr.) Kreissler. The pathogens have a wide spectrum of hosts, such as head cabbage, Chinese cabbage, cauliflower, broccoli, and other crucifers including cultivated and wild grown plants. Alternaria pathogens usually cause damping-off of seedlings, spotting of leaves of cabbages, blackleg of heads of cabbages, and spotting of cauliflower curds and broccoli florets. In oilseed rape, A. brassicae is the dominant invasive species, while in the cruciferous vegetables, both species, A. brassicae, and A. brassicicola are encountered. Infected seeds with spores on the seed coat or mycelium under the seed coat are the main means of distribution for these pathogens. The fungus can overwinter on susceptible weeds or crop debris and on seed plants, as well as on stecklings. Methods for disease prevention and control are based on combining agricultural management practices with chemical control. Using disease-free seeds or seeds treated with fungicides can greatly reduce disease incidence. After appearance of the first symptoms of disease, stringent fungicide spray program is an effective way to reduce losses. Many authors seem to agree, that the most economically feasible method of disease control is the development of resistant Brassicaceae crops varieties, as transgenic approach proved unsuccessful. Due to our increasing understanding of pathogen-host plant interactions, identification of resistance sources, and assessment of the resistance trait inheritance mode, breeding programs of Brassica crops for Alternaria resistance can be enhanced. This is of particular importance since recent years experience dynamic development of ecological and integrated plant production with an emphasis on plant biotic stress resistance. Highly resistant genetic resources have not been reported in Brassica cultivated species, although some varieties differ in their resistance/susceptibility level.

Genome-Wide Association Study of Anthracnose Resistance in Andean Beans (Phaseolus vulgaris)

Abstract: Anthracnose is a seed-borne disease of common bean (Phaseolus vulgaris L.) caused by the fungus Colletotrichum lindemuthianum, and the pathogen is cosmopolitan in distribution. The objectives of this study were to identify new sources of anthracnose resistance in a diverse panel of 230 Andean beans comprised of multiple seed types and market classes from the Americas, Africa, and Europe, and explore the genetic basis of this resistance using genome-wide association mapping analysis (GWAS). Twenty-eight of the 230 lines tested were resistant to six out of the eight races screened, but only one cultivar Uyole98 was resistant to all eight races (7, 39, 55, 65, 73, 109, 2047, and 3481) included in the study. Outputs from the GWAS indicated major quantitative trait loci (QTL) for resistance on chromosomes, Pv01, Pv02, and Pv04 and two minor QTL on Pv10 and Pv11. Candidate genes associated with the significant SNPs were detected on all five chromosomes. An independent QTL study was conducted to confirm the physical location of the Co-1 locus identified on Pv01 in an F4:6 recombinant inbred line (RIL) population. Resistance was determined to be conditioned by the single dominant gene Co-1 that mapped between 50.16 and 50.30 Mb on Pv01, and an InDel marker (NDSU_IND_1_50.2219) tightly linked to the gene was developed. The information reported will provide breeders with new and diverse sources of resistance and genomic regions to target in the development of anthracnose resistance in Andean beans.

A major gene for powdery mildew resistance transferred to common wheat from wild einkorn wheat.

Abstract: A major gene for resistance to wheat powdery mildew (Blumeria graminis f. sp. tritici = Erysiphe graminis f. sp. tritici) has been successfully transferred into hexaploid common wheat (Triticum aestivum, 2n = 6x = 42, AABBDD) from wild einkorn wheat (Triticum monococcum subsp. aegilopoides, 2n = 2x = 14, AA). NC96BGTA5 is a germ plasm line with the pedigree Saluda × 3/PI427662. The response patterns for powdery mildew resistance in NC96BGTA5 were tested with 30 differential isolates of B. graminis f. sp. tritici, and the line was resistant to all tested isolates. The analyses of P1, P2, F1, F2, and BC1F1 populations derived from NC96BGTA5 revealed two genes for wheat powdery mildew resistance in the NC96BGTA5 line. One gene, Pm3a, was from its recurrent parent Saluda, and the second was a new gene introgressed from wild einkorn wheat. The gene was determined to be different from Pm1 to Pm21 by gene-for-gene and pedigree analyses. The new gene was identified as linked to the Pm3a gene based on the...

A rice gene of de novo origin negatively regulates pathogen-induced defense response.

Abstract: How defense genes originated with the evolution of their specific pathogen-responsive traits remains an important problem. It is generally known that a form of duplication can generate new genes, suggesting that a new gene usually evolves from an ancestral gene. However, we show that a new defense gene in plants may evolve by de novo origination, resulting in sophisticated disease-resistant functions in rice. Analyses of gene evolution showed that this new gene, OsDR10, had homologs only in the closest relative, Leersia genus, but not other subfamilies of the grass family; therefore, it is a rice tribe-specific gene that may have originated de novo in the tribe. We further show that this gene may evolve a highly conservative rice-specific function that contributes to the regulation difference between rice and other plant species in response to pathogen infections. Biologic analyses including gene silencing, pathologic analysis, and mutant characterization by transformation showed that the OsDR10-suppressed plants enhanced resistance to a broad spectrum of Xanthomonas oryzae pv. oryzae strains, which cause bacterial blight disease. This enhanced disease resistance was accompanied by increased accumulation of endogenous salicylic acid (SA) and suppressed accumulation of endogenous jasmonic acid (JA) as well as modified expression of a subset of defense-responsive genes functioning both upstream and downstream of SA and JA. These data and analyses provide fresh insights into the new biologic and evolutionary processes of a de novo gene recruited rapidly.