中文摘要：

Brassinosteroids (BR ) 是植物激素的一个主要的组调整植物生长和开发。BRI1，对质膜局部性的蛋白质，当 BR 受体和它被建议了，工作它的 kinase 活动在调整 BR 的植物生长和开发有一个必要角色。这里，我们报导隔离和 bri1 的新等位基因的分子的描述， bri1-301，哪个表演中等词法显型和减少的回答到在正常生长条件下面的 BR。顺序分析从 GG 识别了二底的改变到，导致到在 BRI1 kinase 领域的 989I 的 989G 的变换在。kinase 活动的试管内试金证明 bri1-301 不向 BRI1 底层 TTL 和 BAK1 举办可检测的 autophosphorylation 活动或磷酸化活动。而且，我们的结果建议甚至与极其损害的 kinase 活动， bri1-301 仍然在调整植物生长和开发保留部分功能，它提出 BRI1 kinase 活动是否在高等植物为调停 BR 的生长和开发是必要的问题。

英文摘要：

Brassinosteroids （BRs） are a major group of plant hormones that regulate plant growth and development. BRI1, a protein localized to the plasma membrane, functions as a BR receptor and it has been proposed that its kinase activity has an essential role in BR-regulated plant growth and development. Here we report the isolation and molecular characterization of a new allele of bril, bril-301, which shows moderate morphological phenotypes and a reduced response to BRs under normal growth conditions. Sequence analysis identified a two-base alteration from GG to AT, resulting in a conversion of 989G to 9891 in the BRI1 kinase domain. An in vitro assay of kinase activity showed that bril-301 has no detectable autophosphorylation activity or phosphorylation activity towards the BRI1 substrates TTL and BAK1. Furthermore, our results suggest that bril-301, even with extremely impaired kinase activity, still retains partial function in regulating plant growth and development, which raises the question of whether BRI1 kinase activity is essential for BR-mediated growth and development in higher plants.