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.

VASCULAR ASSOCIATED DEATH1, a Novel GRAM Domain–Containing Protein, Is a Regulator of Cell Death and Defense Responses in Vascular Tissues

Abstract: The hypersensitive response (HR) is a programmed cell death that is commonly associated with plant disease resistance. A novel lesion mimic mutant, vad1 (for vascular associated death1), that exhibits light conditional appearance of propagative HR-like lesions along the vascular system was identified. Lesion formation is associated with expression of defense genes, production of high levels of salicylic acid (SA), and increased resistance to virulent and avirulent strains of Pseudomonas syringae pv tomato. Analyses of the progeny from crosses between vad1 plants and either nahG transgenic plants, sid1, nonexpressor of PR1 (npr1), enhanced disease susceptibility1 (eds1), or non-race specific disease resistance1 (ndr1) mutants, revealed the vad1 cell death phenotype to be dependent on SA biosynthesis but NPR1 independent; in addition, both EDS1 and NDR1 are necessary for the proper timing and amplification of cell death as well as for increased resistance to Pseudomonas strains. VAD1 encodes a novel putative membrane-associated protein containing a GRAM domain, a lipid or protein binding signaling domain, and is expressed in response to pathogen infection at the vicinity of the hypersensitive lesions. VAD1 might thus represent a new potential function in cell death control associated with cells in the vicinity of vascular bundles.

Molecular characterization and functional analysis of MgNLP, the sole NPP1 domain-containing protein, from the fungal wheat leaf pathogen Mycosphaerella graminicola.

Abstract: Analysis of the fully sequenced genome of the wheat leaf-specific fungal pathogen Mycosphaerella graminicola identified only a single gene encoding a member of the necrosis- and ethylene-inducing peptide 1 (Nep1)-like protein family (NLP). NLP proteins have frequently been shown to trigger cell death and the activation of defense signaling reactions in dicotyledonous plants. However, complete loss-of-function reverse genetics analyses for their importance in the virulence of eukaryotic plant pathogens are generally lacking. Real-time quantitative polymerase chain reaction on MgNLP demonstrated the gene to be specifically expressed in planta. Peak expression was observed during the immediate presymptomatic phase of colonization of a susceptible host genotype. This was followed by a dramatic decrease during disease lesion formation which, in this system, exhibits characteristics of host programmed cell death (PCD). No comparable peak in transcript levels was seen during an incompatible interaction with a host genotype exhibiting gene-for-gene-based disease resistance. Heterologously expressed MgNLP protein induced necrotic cell death and the activation of defense-related genes when infiltrated into Arabidopsis leaves but not in leaves of a susceptible wheat genotype. MgNLP infiltration also failed to stimulate wheat mitogen-activated protein kinase activities. Finally, targeted deletion of M. graminicola MgNLP caused no detectable reduction in plant pathogenicity or virulence, suggesting that this protein is not a major virulence determinant during fungal infection of its host plant. To our knowledge, this represents the first complete loss-of-function analysis of NLP in a eukaryotic plant pathogen and we discuss our findings in the context of possible functions for NLP in pathogens which only infect monocotyledonous plants.

Molecular mapping and detection of the yellow rust resistance gene Yr26 in wheat transferred from Triticum turgidum L. using microsatellite markers

Abstract: Yellow rust (stripe rust), caused by Puccinia striiformis Westend f. sp. tritici, is one of the most devastating diseases of wheat throughout the world. Wheat-Haynaldia villosa 6AL.6VS translocation lines R43, R55, R64 and R77, derived from the cross of three species, carry resistance to both yellow rust and powdery mildew. An F2 population was established by crossing R55 with the susceptible cultivar Yumai 18. The yellow rust resistance in R55 was controlled by a single dominant gene, which segregated independently of the powdery mildew resistance gene Pm21 located in the chromosome 6VS segment, indicating that the yellow rust resistance gene and Pm21 are unlikely to be carried by the same alien segment. This yellow rust resistance gene was considered to beYr26, originally thought to be also located in chromosome arm 6VS. Bulked Segregation Analysis and microsatellite primer screens of the population F2 of Yumai 18 × R55 identified three chromosome 1B microsatellite locus markers, Xgwm11, Xgwm18 and Xgwm413, closely linked to Yr26. Yr26 was placed 1.9 cM distal of Xgwm11/Xgwml8, which in turn were 3.2 cM from Xgwm413. The respective LOD values were 21 and 36.5. Therefore, Yr26 was located in the short arm of chromosome 1B. The origin and distribution of Yr26 was investigated by pedigree, inheritance of resistance and molecular marker analysis. The results indicated that Yr26 came from Triticum turgidum L. Three other 6AL.6VS translocation lines, R43, R64 and R77, also carried Yr26. These PCR-based microsatellite markers were shown to be very effective for the detection of the Yr26 gene in segregating populations and therefore can be applied in wheat breeding.

A novel blast resistance gene, Pi54rh cloned from wild species of rice, Oryza rhizomatis confers broad spectrum resistance to Magnaporthe oryzae.

Abstract: The dominant rice blast resistance gene, Pi54 confers resistance to Magnaporthe oryzae in different parts of India. In our effort to identify more effective forms of this gene, we isolated an orthologue of Pi54 named as Pi54rh from the blast-resistant wild species of rice, Oryza rhizomatis, using allele mining approach and validated by complementation. The Pi54rh belongs to CC-NBS-LRR family of disease resistance genes with a unique Zinc finger (C(3)H type) domain. The 1,447 bp Pi54rh transcript comprises of 101 bp 5'-UTR, 1,083 bp coding region and 263 bp 3'-UTR, driven by pathogen inducible promoter. We showed the extracellular localization of Pi54rh protein and the presence of glycosylation, myristoylation and phosphorylation sites which implicates its role in signal transduction process. This is in contrast to other blast resistance genes that are predicted to be intracellular NBS-LRR-type resistance proteins. The Pi54rh was found to express constitutively at basal level in the leaves, but upregulates 3.8-fold at 96 h post-inoculation with the pathogen. Functional validation of cloned Pi54rh gene using complementation test showed high degree of resistance to seven isolates of M. oryzae collected from different geographical locations of India. In this study, for the first time, we demonstrated that a rice blast resistance gene Pi54rh cloned from wild species of rice provides broad spectrum resistance to M. oryzae hence can be used in rice improvement breeding programme.

Induced Mutations in Plant Breeding

Abstract: 1 Introduction- 2 Methods for Inducing Mutations- 21 Mutagenic Agents and Related Problems- 22 The Chimerical Structure of the M1 Plants- 3 The Selection Value of Mutant Genes- 4 The Seed Production of Mutants and the Alteration of Quantitative Characters- 41 The Alteration of Quantitative Characters- 42 Mutants with Increased Seed Yield- 43 Released or Approved Mutant Varieties- 5 The Utilization of Mutants in Crossbreeding- 51 The Incorporation of Mutant Genes into the Genomes of Varieties or Strains- 52 The Joint Action of Mutant Genes- 521 Negative Interactions- 522 Positive Interactions- 6 The Alteration of the Shoot System by Means of Mutations- 61 Mutants with Reduced Plant Height: Erectoides Types, Semidwarfs, Dwarfs- 611 Barley- 612 Rice- 613 Bread and Durum Wheat Other Gramineae- 614 Dicotyledonous Crops- 62 Mutants with Increased Plant Height- 63 Mutants with Altered Stem Structure- 631 Branching, Tillering- 632 Stem Bifurcation- 6321 Bifurcated Mutants- 6322 Bifurcated Recombinants- 633 Stem Fasciation- 6331 Fasciated Mutants- 6332 Fasciated Recombinants- 634 Mutations in Fiber Plants- 7 Alterations of Flower Shape, Color and Function- 71 Flower Shapes and Flower Colors in Ornamentals- 72 Inflorescences- 73 Genetic Male Sterility- 8 Leaf Mutants of Agronomic Interest- 9 Mutations Affecting the Root System- 10 The Alteration of Flowering and Ripening Times- 101 Earliness- 102 Lateness- 103 Changes of the Photoperiodic Reaction- 11 Mutations in Vegetatively Propagated Crops and Ornamentals- 12 Heterosis- 13 Disease Resistance- 131 Resistance Against Fungi, Bacteria, and Viruses- 1311 Barley- 1312 Rice- 1313 Bread and Durum Wheat- 1314 Oats- 1315 Maize- 1316 Pearl Millet- 1317 Sugarcane- 1318 Dicotyledonous Crops- 132 Resistance Against Animal Pathogens- 133 Herbicide Tolerance- 14 Drought Resistance, Heat Tolerance, Winterhardiness- 15 Shattering and Shedding Resistance- 16 The Pleiotropic Gene Action as a Negative Factor in Mutation Breeding- 161 The Alteration of Pleiotropic Patterns Under the Influence of Changed Genotypic Background or Environment- 162 Mutations of Closely Linked Genes- 17 The Penetrante Behavior of Mutant Genes as a Negative Factor- 18 The Adaptability of Mutants to Altered Environmental Conditions- 181 The Reaction of Mutants to Different Natural Environments- 182 The Reaction of Mutants Under Controlled Phytotron Conditions- 19 The Alteration of Morphological and Physiological Seed Characters- 191 Seed Size- 192 Seed Shape- 193 Seed Color- 194 Physiological Seed Characters- 20 The Alteration of Seed Storage Substances- 201 Seed Proteins- 2011 The Characterization of Seed Proteins- 2012 Factors Influencing Protein Content and Composition- 20121 Environmental Factors- 20122 Endogenous Factors- 2013 Seed Protein Content of Different Varieties of the Same Species- 2014 Alteration of Seed Proteins Through Mutant Genes- 20141 Protein Mutants in Cereals- 20142 Protein Mutants in Legumes- 202 Seed Carbohydrates- 2021 Maize- 2022 Barley and Other Cereals- 2023 Peas- 203 Seed Lipids- 21 Other Plant Substances- 22 The Nutritional Value of Mutants- 221 Maize Mutants- 222 Barley Mutants- 223 Sorghum Genotypes- 224 Pea Mutants- 23 General Aspects of Mutation Breeding with Regard to the Improvement of Seed Storage Substances- References