RRC ID 81424
Author Keisuke Kariya, Haruka Mori, Makoto Ueno, Takanori Yoshikawa, Masayoshi Teraishi, Yukinori Yabuta, Kotomi Ueno, Atsushi Ishihara
Title Identification and evolution of a diterpenoid phytoalexin oryzalactone biosynthetic gene in the genus Oryza
Journal The Plant Journal
Abstract SUMMARYThe natural variation of plant‐specialized metabolites represents the evolutionary adaptation of plants to their environments. However, the molecular mechanisms that account for the diversification of the metabolic pathways have not been fully clarified. Rice plants resist attacks from pathogens by accumulating diterpenoid phytoalexins. It has been confirmed that the composition of rice phytoalexins exhibits numerous natural variations. Major rice phytoalexins (momilactones and phytocassanes) are accumulated in most cultivars, although oryzalactone is a cultivar‐specific compound. Here, we attempted to reveal the evolutionary trajectory of the diversification of phytoalexins by analyzing the oryzalactone biosynthetic gene in Oryza species. The candidate gene, KSLX‐OL, which accounts for oryzalactone biosynthesis, was found around the single‐nucleotide polymorphisms specific to the oryzalactone‐accumulating cultivars in the long arm of chromosome 11. The metabolite analyses in Nicotiana benthamiana and rice plants overexpressing KSLX‐OL indicated that KSLX‐OL is responsible for the oryzalactone biosynthesis. KSLX‐OL is an allele of KSL8 that is involved in the biosynthesis of another diterpenoid phytoalexin, oryzalexin S and is specifically distributed in the AA genome species. KSLX‐NOL and KSLX‐bar, which encode similar enzymes but are not involved in oryzalactone biosynthesis, were also found in AA genome species. The phylogenetic analyses of KSLXs, KSL8s, and related pseudogenes (KSL9s) indicated that KSLX‐OL was generated from a common ancestor with KSL8 and KSL9 via gene duplication, functional differentiation, and gene fusion. The wide distributions of KSLX‐OL and KSL8 in AA genome species demonstrate their long‐term coexistence beyond species differentiation, suggesting a balancing selection between the genes.
Volume 118
Pages 358-372
Published 2024-4-1
DOI 10.1111/tpj.16608
PMID 38194491
MeSH Diterpenes* / metabolism Oryza* / genetics Oryza* / metabolism Phylogeny Phytoalexins Plant Proteins / genetics Plant Proteins / metabolism Sesquiterpenes* / metabolism
Resource
Rice W0106 W0120 W0137 W0180 W0593 W0630 W1230 W1236 W1294 W1551 W1669 W1681 W1715 W1807 W1866 W1886 W1921 W1945 W1962 W1965 W1976 W1981 W2003 W2051 W2057 W2078 W2109 W2263 W2114 W2117