Biology subjects

Ronald, P.

Publications and source records attributed to Ronald, P..

3 recordsLinked to original sources

bioRxiv2017

Distribution and inheritance of a gene cluster encoding a sulfated tyrosine peptide in Xanthomonas spp.

The rice XA21-mediated immune response is activated upon recognition of the RaxX peptide produced by the bacterium Xanthomonas oryzae pv. oryzae (Xoo). The 60 residue RaxX precursor is posttranslationally modified to form a sulfated tyrosine peptide that shares sequence and functional similarity with the plant sulfated tyrosine (PSY) peptide hormones. The five kb raxX-raxSTAB gene cluster of Xoo encodes RaxX, the RaxST tyrosylprotein sulfotransferase, and the RaxA and RaxB components of a predicted type one secretion system. The identified the complete raxX-raxSTAB gene cluster is present only in Xanthomonas spp., in five distinct lineages in addition to X. oryzae. The phylogenetic distribution of the raxX-raxSTAB gene cluster is consistent with the occurrence of multiple lateral transfer events during Xanthomonas speciation. RaxX variants representing each of the five lineages, and three Xoo RaxX variants, fail to activate the XA21-mediated immune response yet retain peptide hormone activity. These RaxX variants contain a restricted set of missense mutations, consistent with the hypothesis that selection acts to maintain peptide hormone-like function. These observations are also consistent with the hypothesis that the XA21 receptor evolved specifically to recognize Xoo RaxX.

microbiology↗

bioRxiv2017

The Rice XA21 Ectodomain Fused to the Arabidopsis EFR Cytoplasmic Domain Confers Resistance to Xanthomonas oryzae pv. oryzae

O_LIRice (Oryza sativa) plants expressing the XA21 cell surface receptor kinase are resistant to Xanthomonas oryzae pv.oryzae (Xoo) infection. We previously demonstrated that expressing a chimeric protein containing the EFR (ELONGATION FACTOR Tu RECEPTOR) ectodomain and the XA21 endodomain (EFR:XA21) in rice does not confer robust resistance to Xoo.\nC_LIO_LITo test if the XA21 ectodomain is required for Xoo resistance, we produced transgenic rice lines expressing a chimeric protein consisting of the XA21 ectodomain and EFR endodomain (XA21:EFR) and inoculated these lines with Xoo. We also tested if the XA21:EFR rice plants respond to a synthetic sulfated 21 amino acid derivative (RaxX21-sY) derived from the activator of XA21-mediated immunity, RaxX.\nC_LIO_LIWe found that five independently transformed XA21:EFR rice lines displayed resistance to Xoo as measured by lesion length analysis, and showed that five lines express markers of the XA21 defense response (generation of reactive oxygen species and defense response gene expression) after treatment with RaxX21-sY.\nC_LIO_LIOur results indicate that expression of the XA21:EFR chimeric receptor in rice confers resistance to Xoo. These results suggest that the endodomain of the EFR and XA21 immune receptors are interchangeable and the XA21 ectodomain is the key determinant conferring robust resistance to Xoo.\nC_LI

plant biology↗

bioRxiv2017

WheatNet: A genome-scale functional network for hexaploid bread wheat, Triticum aestivum

Gene networks provide a system-level overview of genetic organizations and enable the dissection of functional modules underlying complex traits. Here we report the generation of WheatNet, the first genome-scale functional network for T. aestivum and a companion web server (www.inetbio.org/wheatnet). WheatNet was constructed by integrating 20 distinct genomics datasets, including 156,000 wheat-specific co-expression links mined from 1,929 microarray data. A unique feature of WheatNet is that each network node represents either a single gene or a group of genes. We computationally partitioned gene groups mimicking homeologous genes by clustering 99,386 wheat genes, resulting in 20,248 gene groups comprising 63,401 genes and 35,985 individual genes. Thus, WheatNet was constructed using 56,233 nodes, and the final integrated network has 20,230 nodes and 567,000 edges. The edge information of the integrated WheatNet and all 20 component networks are available for download.

genetics↗