Biology subjects

Ridout, C. J.

Publications and source records attributed to Ridout, C. J..

3 recordsLinked to original sources

bioRxiv2023

Pathogen lifestyle defines host genetic signature of quantitative disease resistance in oilseed rape (Brassica napus)

O_LICrops are affected by several pathogens, but these are rarely studied in parallel to identify common and unique genetic factors controlling diseases. Broad-spectrum quantitative disease resistance (QDR) is desirable for crop breeding as it confers resistance to several pathogen species. C_LIO_LIHere, we use associative transcriptomics (AT) to identify candidate gene loci associated with Brassica napus QDR to four contrasting fungal pathogens: Alternaria brassicicola, Botrytis cinerea, Pyrenopeziza brassicae and Verticillium longisporum. C_LIO_LIWe did not identify any loci associated with broad-spectrum QDR to fungal pathogens with contrasting lifestyles. Instead, we observed QDR dependent on the lifestyle of the pathogen--hemibiotrophic and necrotrophic pathogens had distinct QDR responses and associated loci, including some loci associated with early immunity. Furthermore, we identify a genomic deletion associated with resistance to V. longisporum and potentially broad-spectrum QDR. C_LIO_LIThis is the first time AT has been used for several pathosystems simultaneously to identify host genetic loci involved in broad-spectrum QDR. C_LIO_LIWe highlight candidate loci for broad-spectrum QDR with no antagonistic effects on susceptibility to the other pathogens studies as candidates for crop breeding. C_LI

plant biology↗

bioRxiv2019

Mildew Locus O facilitates colonization by arbuscular mycorrhiza in angiosperms

O_LILoss of barley Mildew Resistance Locus O (MLO) is known to confer durable and robust resistance to powdery mildew (Blumeria graminis), a biotrophic fungal leaf pathogen. Based on the increased expression of MLO in mycorrhizal roots and its presence in a clade of the MLO family that is specific to mycorrhizal-host species, we investigated the potential role of MLO in arbuscular mycorrhizal interactions. C_LIO_LIUsing mutants from barley, wheat, and Medicago truncatula, we demonstrate a role for MLO in colonization by the arbuscular mycorrhizal fungi Rhizophagus irregularis. C_LIO_LIEarly mycorrhizal colonization was reduced in mlo mutants of barley, wheat and Medicago truncatula, and this was accompanied by a pronounced decrease in the expression of many of the key genes required for intracellular accommodation of arbuscular mycorrhizal fungi. C_LIO_LIThese findings suggest that the primary role of MLO in angiosperms is in the establishment of symbiotic associations with beneficial fungi, which has been appropriated by powdery mildew. C_LI

plant biology↗

bioRxiv2018

Physical and transcriptional organisation of the bread wheat intracellular immune receptor repertoire

Disease resistance genes encoding intracellular immune receptors of the nucleotide-binding and leucine-rich repeat (NLR) class of proteins detect pathogens by the presence of pathogen effectors. Plant genomes typically contain hundreds of NLR encoding genes. The availability of the hexaploid wheat cultivar Chinese Spring reference genome now allows a detailed study of its NLR complement. However, low NLR expression as well as high intra-family sequence homology hinders their accurate gene annotation. Here we developed NLR-Annotator for in silico NLR identification independent of transcript support. Although developed for wheat, we demonstrate the universal applicability of NLR-Annotator across diverse plant taxa. Applying our tool to wheat and combining it with a transcript-validated subset of genes from the reference gene annotation, we characterized the structure, phylogeny and expression profile of the NLR gene family. We detected 3,400 full-length NLR loci of which 1,540 were confirmed as complete genes. NLRs with integrated domains mostly group in specific sub-clades. Members of another subclade predominantly locate in close physical proximity to NLRs carrying integrated domains suggesting a paired helper-function. Most NLRs (88%) display low basal expression (in the lower 10 percentile of transcripts), which may be tissue-specific and/or induced by biotic stress. As a case study for applying our tool to the positional cloning of resistance genes, we estimated the number of NLR genes within the intervals of mapped rust resistance genes. Our study will support the identification of functional resistance genes in wheat to accelerate the breeding and engineering of disease resistant varieties.

plant biology↗