茉莉酸信号转导突变体ber15的分离和基因克隆表明油菜素内酯的合成影响茉莉酸信号转导

Characterization of Jasmonic Acid Response Mutant ber15 Demonstrates Cross Talk Between Jasmonic Acid and Brassinosteriod Signaling

bestatin是一种氨肽酶抑制剂,能够激活茉莉酸信号转导途径而诱导抗性相关基因的表达,从而为用化学遗传学手段解析茉莉酸途径提供了一个有效的工具。ber15是我们鉴定到的一个对bestatin不敏感的拟南芥突变体,随后的研究表明该突变体对外源茉莉酸的敏感性也明显降低,表明相应的野生型基因BER15在茉莉酸信号转导中起重要作用。图位克隆结果表明BER15编码一个细胞色素P450单加氧酶,是植物激素油菜素内酯合成途径中的一个关键酶。对BER15基因功能的深入研究将会为了解油菜素内酯的合成与茉莉酸信号途径间的互作关系提供证据。

Bestatin, an inhibitor of some aminopeptidases, potently activates jasmonic acid-induced defense genes expression in the model systems of tomato and Arabidopsis. We have employed bestatin as a small molecular chemical tool to dissect jasmonic acid signaling in Arabidopsis and identified a collection of bestatin response （her） mutants, ber15 is one of these mutants that are resistant to the inhibitory effect of bestatin on root elongation. Subsequent investigation revealed that ber15 is less sensitive to applied jasmonic acid in term of root growth inhibition, suggesting that the BER15 gene play a role in JA signaling. Map-based cloning of BER15 demonstrated BER15 encodes a cytochrome P450 monooxygenase which acts as a key enzyme in brassinolide synthesis. Further functional analysis of BER15 will broaden our knowledge of the interaction mechanism between brassinolide biosynthesis and JA signaling.