Evolutionary trajectory of phytoalexin biosynthetic gene clusters in rice

作者：Koji Miyamoto, Masahiro Fujita, Matthew Shenton, Shota Akashi, Chizu Sugawara, Arisa Sakai, Kiyotaka Horie, Morifumi Hasegawa, Hiroshi Kawaide, Wataru Mitsuhashi, Hideaki Nojiri, Hisakazu Yamane, Nori Kurata, Kazunori Okada, Tomonobu Toyomasu · 发表于：The Plant Journal · 年份：2016 · DOI：10.1111/tpj.13200 · 被引用次数：104 · 研究领域：Plant biochemistry and biosynthesis、Photosynthetic Processes and Mechanisms、Plant Gene Expression Analysis

Plants frequently possess operon-like gene clusters for specialized metabolism. Cultivated rice, Oryza sativa, produces antimicrobial diterpene phytoalexins represented by phytocassanes and momilactones, and the majority of their biosynthetic genes are clustered on chromosomes 2 and 4, respectively. These labdane-related diterpene phytoalexins are biosynthesized from geranylgeranyl diphosphate via ent-copalyl diphosphate or syn-copalyl diphosphate. The two gene clusters consist of genes encoding diterpene synthases and chemical-modification enzymes including P450s. In contrast, genes for the biosynthesis of gibberellins, which are labdane-related phytohormones, are scattered throughout the rice genome similar to other plant genomes. The mechanism of operon-like gene cluster formation remains undefined despite previous studies in other plant species. Here we show an evolutionary insight into the rice gene clusters by a comparison with wild Oryza species. Comparative genomics and biochemical studies using wild rice species from the AA genome lineage, including Oryza barthii, Oryza glumaepatula, Oryza meridionalis and the progenitor of Asian cultivated rice Oryza rufipogon indicate that gene clustering for biosynthesis of momilactones and phytocassanes had already been accomplished before the domestication of rice. Similar studies using the species Oryza punctata from the BB genome lineage, the distant FF genome lineage species Oryza brachyantha and an outgroup species Leersia p...