Plant Breeding For Disease Resistance Research Articles

Analysis of Clade V MLO Gene Expressions in Hazelnut Leaves upon Exposure to Powdery Mildew

Powdery mildew affecting European hazelnut Corylus avellana L. trees in Turkey is caused by the obligate biotrophic fungus Erysiphe corylacearum. This fungal disease causes significant economic losses by reducing the yield and quality of hazelnuts. Loss-of-function mutations in the mildew resistance locus o (MLO) gene family of many plants confer high levels of broad-spectrum resistance to powdery mildew. The proteins encoded by the genes at the MLO locus are divided into approximately seven different conserved clades. Among them, the phylogenetic clade V has been shown to be involved in PM susceptibility, as inactivation of these genes leads to long-term disease resistance in dicotyledons. In this study, we examined the temporal expression pattern of three hazelnut MLO genes, previously identified as clade V, in response to powdery mildew infection in C. avellana cv. Tombul. Leaves are the main tissue affected by the powdery mildew pathogen in hazelnut plants. Analysis of MLO expression in hazelnut leaves showed that CavMLO2 and CavMLO6 were significantly upregulated after challenge with E. corylacearum, providing preliminary evidence that they may be involved in PM susceptibility. Thus, these results present a basis for the isolation and use of relevant genes in plant breeding for disease resistance. Moreover, expression profiles of the clade V MLO genes are also important to identify candidate genes that need to be silenced or edited for future molecular studies to obtain resistant hazelnut varieties.

Genotype-Ideotype distance index and multivariate analysis to select sources of anthracnose resistance in Capsicum spp.

The challenges of plant breeding for disease resistance include identifying genotypes that are resistant to more than one pathogen isolate and defining adequate methods for measuring resistance. We report the identification of Capsicum spp. genotypes resistant to anthracnose caused by two Colletotrichum scovillei isolates using the Genotype-Ideotype Distance Index (GIDI) and multivariate analysis. Forty-one genotypes of chili peppers from three Capsicum species considering unripe and ripe fruits were evaluated for resistance to anthracnose. For inoculation, 20 μL of a suspension containing 1 × 106 conidia/mL were applied in each fruit. Analyses were performed daily for eight days using a scale from 1 (resistant) to 9 (susceptible). Area under the disease progress curve (AUDPC), incubation period, and latent period were evaluated in unripe and ripe fruits, and analyzed using a non-parametric test with ANOVA-type statistic and correlated using the Spearman method. Genotypes were classified using the GIDI and Ward’s hierarchical clustering method. There was variability in germplasm resistance to anthracnose considering the resistance variables and the stage of fruit development. GIDI allowed identifying nine C. baccatum var. pendulum genotypes resistant to isolate 13, and eight C. baccatum var. pendulum plus one C. annuum genotypes resistant to isolate 8. GIDI and Ward’s clustering method identified the same genotypes resistant to isolate 8. Finding resistance in Capsicum genotypes representing different genic complexes means that breeders would be able to introgress resistant alleles from non-cultivated or semi-domesticated into cultivated plants. One genotype, UENF 1628 (C. baccatum var. pendulum), was resistant to two pathogen isolates representing a very interesting source of resistance to anthracnose caused by C. scovillei.

Hyperspectral Canopy Sensing of Wheat Septoria Tritici Blotch Disease.

Producing quantitative and reliable measures of crop disease is essential for resistance breeding, but is challenging and time consuming using traditional phenotyping methods. Hyperspectral remote sensing has shown potential for the detection of plant diseases, but its utility for phenotyping large and diverse populations of plants under field conditions requires further evaluation. In this study, we collected canopy hyperspectral data from 335 wheat varieties using a spectroradiometer, and we investigated the use of canopy reflectance for detecting the Septoria tritici blotch (STB) disease and for quantifying the severity of infection. Canopy- and leaf-level infection metrics of STB based on traditional visual assessments and automated analyses of leaf images were used as ground truth data. Results showed (i) that canopy reflectance and the selected spectral indices show promise for quantifying STB infections, and (ii) that the normalized difference water index (NDWI) showed the best performance in detecting STB compared to other spectral indices. Moreover, partial least squares (PLS) regression models allowed for an improvement in the prediction of STB metrics. The PLS discriminant analysis (PLSDA) model calibrated based on the spectral data of four reference varieties was able to discriminate between the diseased and healthy canopies among the 335 varieties with an accuracy of 93% (Kappa = 0.60). Finally, the PLSDA model predictions allowed for the identification of wheat genotypes that are potentially more susceptible to STB, which was confirmed by the STB visual assessment. This study demonstrates the great potential of using canopy hyperspectral remote sensing to improve foliar disease assessment and to facilitate plant breeding for disease resistance.

Mini Review: Potential Applications of Non-host Resistance for Crop Improvement.

Plant breeding for disease resistance is crucial to sustain global crop production. For decades, plant breeders and researchers have extensively used host plant resistance genes (R-genes) to develop disease resistant cultivars. However, the general instability of R-genes in crop cultivars when challenged with diverse pathogen populations emphasizes the need for more stable means of resistance. Alternatively, non-host resistance is recognized as the most durable, broad-spectrum form of resistance against the majority of potential pathogens in plants and has gained great attention as an alternative target for managing resistance. While transgenic approaches have been utilized to transfer non-host resistance to host species, conventional breeding applications have been more elusive. Nevertheless, avenues for discovery and deployment of genetic loci for non-host resistance via hybridization are increasingly abundant, particularly when transferring genes among closely related species. In this mini review, we discuss current and developing applications of non-host resistance for crop improvement with a focus on the overlap between host and non-host mechanisms and the potential impacts of new technology.

Plant breeding for disease resistance in the age of effectors

BiographyRichard Peter Oliver born in the United Kingdom in1958. Prof. of Physiological and Molecular PlantPathology, Murdoch U., Australia, and Director of theAustralian Centre for Necrotrophic Fungal Pathogens(ACNFP). BSc (1979) and PhD (1982) in Biochemistryfrom the U. of Bristol, UK, with a thesis focussing on theenzyme protochlorophyllide oxidoreductase. EMBO fel-low at the Carlsberg Laboratory (Denmark) with Prof.Diter von Wettstein researching the molecular biology ofthe barley plastid genome 1982–84. Lectureship at the U.of East Anglia was his first introduction to plantpathology and he concentrated on developing moleculartools for fungal pathogens (especially Cladosporiumfulvum) andresearchingdiseaseresistanceinArabidopsistofungalpathogens,suchaspowderymildew(1984 –96).Returned to the Carlsberg Laboratory as Prof. and HeadofthePhysiologyDept.andcontinuedresearchonC.fulvum as well as developing genomic tools for barleypowdery mildew (1996–2000). A short stay at Zeneca(UK) was followed by a move to Australia (2000) tostart the ACNFP with the goal of understanding foliarnecrotrophic pathogens, especially Stagonosporanodorum. Since 2000 the centre has developed fullscale omics tools for S. nodorum including thegenome sequence, transcriptomics, proteomics andmetabolomics. Publications: 120 refereed papers,180 other papers, edited two books. Founding senioreditor of Molecular Plant Pathology,senioreditorofMolecular Plant-Microbe Interactions.Numerouseditorial board and ad-hoc editing roles. CurrentResearch: Pathogenic mechanisms of Pleosporaleanfungi, disease resistance in Medicago truncatula,genetics mapping in legumes.

Plant breeding for disease resistance

Plant breeding for Pest and Disease Resistance. By G. E. Russell. Pp. 485. (Butterworths: London, 1978.) £25.

Crop Ecology and Plant Breeding for Disease Resistance

Crop Ecology and Plant Breeding for Disease Resistance

Symposium on Plant Breeding for Disease Resistance

Agronomy JournalVolume 17, Issue 12 p. 814-814 Agronomic Affair Symposium on Plant Breeding for Disease Resistance First published: 01 December 1925 https://doi.org/10.2134/agronj1925.00021962001700120012xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume17, Issue12December 1925Pages 814-814 RelatedInformation