Role of SGT1 in resistance protein accumulation in plant immunity
Role of SGT1 in resistance protein accumulation in plant immunity
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DOI：
10.1038/sj.emboj.7601084
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发表时间：
2006-05-03
期刊：
影响因子：
11.4
通讯作者：
Shirasu, Ken
中科院分区：
文献类型：
--
作者：
Azevedo, Cristina;Betsuyaku, Shigeyuki;Shirasu, Ken
高度保守的真核蛋白 SGT1 与分子伴侣 HSP90 特异性结合。在植物中，SGT1 积极调节许多抗病 (R) 蛋白赋予的抗病性以及对植物激素、生长素的发育反应。我们发现本塞姆氏烟草中 SGT1 的沉默会导致 R 蛋白 Rx 的稳态水平降低。这些数据支持 SGT1 在 R 蛋白积累中的作用，可能是在复杂组装水平上。在拟南芥中，两种 SGT1 蛋白 AtSGT1a 和 AtSGT1b 在发育早期存在功能冗余。 AtSGT1a 和 AtSGT1b 在感染后在叶子中被诱导，一旦达到一定水平，任一蛋白都可以发挥抗性作用，具体取决于测试的 R 蛋白。在未受到攻击的组织中，稳态 AtSGT1b 水平至少是 AtSGT1a 的四倍。虽然 SGT1a 和 SGT1b 各自的四肽重复 (TPR) 结构域控制蛋白质积累，但它们对于 SGT1 在抗性和生长素反应中的内在功能来说是可有可无的。
A highly conserved eukaryotic protein SGT1 binds specifically to the molecular chaperone, HSP90. In plants, SGT1 positively regulates disease resistance conferred by many Resistance (R) proteins and developmental responses to the phytohormone, auxin. We show that silencing of SGT1 in Nicotiana benthamiana causes a reduction in steady-state levels of the R protein, Rx. These data support a role of SGT1 in R protein accumulation, possibly at the level of complex assembly. In Arabidopsis, two SGT1 proteins, AtSGT1a and AtSGT1b, are functionally redundant early in development. AtSGT1a and AtSGT1b are induced in leaves upon infection and either protein can function in resistance once a certain level is attained, depending on the R protein tested. In unchallenged tissues, steady-state AtSGT1b levels are at least four times greater than AtSGT1a. While the respective tetratricopeptide repeat (TPR) domains of SGT1a and SGT1b control protein accumulation, they are dispensable for intrinsic functions of SGT1 in resistance and auxin responses.