germine and jasmonic-acid

In rice (Oryza sativa L.), crown roots (CRs) have many important roles in processes such as root system expansion, water and mineral uptake, and adaptation to environmental stresses. Phytohormones such as auxin, cytokinin, and ethylene are known to control CR initiation and development in rice. However, the role of jasmonic acid (JA) in CR development remained elusive. Here, we report that JA promotes CR development by regulating OsGER4, a rice Germin-like protein. Root phenotyping analysis revealed that exogenous JA treatment induced an increase in CR number in a concentration-dependent manner. A subsequent genome-wide association study and gene expression analyses pinpointed a strong association between the Germin-like protein OsGER4 and the increase in CR number under exogenous JA treatment. The ProGER4::GUS reporter line showed that OsGER4 is a hormone-responsive gene involved in various stress responses, mainly confined to epidermal and vascular tissues during CR primordia development and to vascular bundles of mature crown and lateral roots. Notable changes in OsGER4 expression patterns caused by the polar auxin transport inhibitor NPA support its connection to auxin signaling. Phenotyping experiments with OsGER4 knockout mutants confirmed that this gene is required for CR development under exogenous JA treatment. Overall, our results provide important insights into JA-mediated regulation of CR development in rice.

Topics: Gene Expression Regulation, Plant; Genome-Wide Association Study; Indoleacetic Acids; Oryza; Plant Proteins; Plant Roots

This is the first report that GLP gene (OsGLP2-1) is involved in panicle blast and bacterial blight resistance in rice. In addition to its resistance to blast and bacterial blight, OsGLP2-1 has also been reported to co-localize with a QTLs for sheath blight resistance in rice. These suggest that the disease resistance provided by OsGLP2-1 is quantitative and broad spectrum. Its good resistance to these major diseases in rice makes it to be a promising target in rice breeding. Rice (Oryza sativa) blast caused by Magnaporthe oryzae and bacterial blight caused by Xanthomonas oryzae pv. oryzae are the two most destructive rice diseases worldwide. Germin-like protein (GLP) gene family is one of the important defense gene families which have been reported to be involved in disease resistance in plants. Although GLP proteins have been demonstrated to positively regulate leaf blast resistance in rice, their involvement in resistance to panicle blast and bacterial blight, has not been reported. In this study, we reported that one of the rice GLP genes, OsGLP2-1, was significantly induced by blast fungus. Overexpression of OsGLP2-1 quantitatively enhanced resistance to leaf blast, panicle blast and bacterial blight. The temporal and spatial expression analysis revealed that OsGLP2-1is highly expressed in leaves and panicles and sub-localized in the cell wall. Compared with empty vector transformed (control) plants, the OsGLP2-1 overexpressing plants exhibited higher levels of H

Topics: Cyclopentanes; Disease Resistance; Gene Expression Regulation, Plant; Glycoproteins; Hydrogen Peroxide; Magnaporthe; Oryza; Oxylipins; Plant Diseases; Plant Growth Regulators; Plant Proteins; Plants, Genetically Modified; Xanthomonas

A germin-like gene (CchGLP) cloned from geminivirus-resistant pepper (Capsicum chinense Jacq. Line BG-3821) was characterized and the enzymatic activity of the expressed protein analyzed. The predicted protein consists of 203 amino acids, similar to other germin-like proteins. A highly conserved cupin domain and typical germin boxes, one of them containing three histidines and one glutamate, are also present in CchGLP. A signal peptide was predicted in the first 18 N-terminal amino acids, as well as one putative N-glycosylation site from residues 44-47. CchGLP was expressed in E. coli and the recombinant protein displayed manganese superoxide dismutase (Mn-SOD) activity. Molecular analysis showed that CchGLP is present in one copy in the C. chinense Jacq. genome and was induced in plants by ethylene (Et) and salicylic acid (SA) but not jasmonic acid (JA) applications in the absence of pathogens. Meanwhile, incompatible interactions with either Pepper golden mosaic virus (PepGMV) or Pepper huasteco yellow vein virus (PHYVV) caused local and systemic CchGLP induction in these geminivirus-resistant plants, but not in a susceptible accession. Compatible interactions with PHYVV, PepGMV and oomycete Phytophthora capsici did not induce CchGLP expression. Thus, these results indicate that CchGLP encodes a Mn-SOD, which is induced in the C. chinense geminivirus-resistant line BG-3821, likely using SA and Et signaling pathways during incompatible interactions with geminiviruses PepGMV and PHYVV.

Topics: Capsicum; Cloning, Molecular; Computational Biology; Cyclopentanes; Disease Resistance; Escherichia coli; Ethylenes; Geminiviridae; Gene Expression Regulation, Plant; Glycoproteins; Mosaic Viruses; Oxylipins; Phytophthora; Plant Diseases; Plant Proteins; Recombinant Proteins; Salicylic Acid; Sequence Analysis, DNA; Superoxide Dismutase