熱激蛋白90（Hsp90）家族是一類(lèi)進(jìn)化上非常保守的熱激蛋白,，廣泛存在于動(dòng)植物和真菌中。作為一種重要的分子伴侶,，Hsp90參與多種生理過(guò)程,，如信號(hào)傳導(dǎo)、蛋白質(zhì)折疊和降解等,。Hsp90在細(xì)胞質(zhì),、線粒體、葉綠體和內(nèi)質(zhì)網(wǎng)中都有分布,。此前的研究表明,，胞質(zhì)Hsp90在調(diào)控植物的生長(zhǎng)發(fā)育、抗病耐逆過(guò)程、緩沖遺傳變異等方面具有重要功能,，但已有的研究主要集中在擬南芥和煙草等雙子葉模式植物上,，而在單子葉植物，如小麥中尚未進(jìn)行系統(tǒng)研究,。因此,，對(duì)小麥胞質(zhì)Hsp90家族進(jìn)行系統(tǒng)鑒定和生物學(xué)功能研究，對(duì)深入認(rèn)識(shí)小麥生長(zhǎng)發(fā)育調(diào)控和抗病耐逆過(guò)程具有重要的理論意義,，對(duì)小麥品種改良也具有應(yīng)用價(jià)值,。
中國(guó)科學(xué)院遺傳與發(fā)育生物學(xué)研究所張相岐研究組和王道文研究組合作，對(duì)小麥胞質(zhì)Hsp90基因家族進(jìn)行了系統(tǒng)鑒定和功能分析,。首先,，根據(jù)植物Hsp90基因保守序列設(shè)計(jì)引物，通過(guò)PCR擴(kuò)增和篩選普通小麥BAC文庫(kù)等方法獲得了9個(gè)胞質(zhì)Hsp90基因的cDNA和基因組DNA序列,。從結(jié)構(gòu)上,，這9個(gè)基因可明顯分為3組，即TaHsp90.1,，TaHsp90.2和TaHsp90.3,。染色體定位表明，這3組TaHsp90基因分別位于第2,、7和5同源群染色體上,，每組有3個(gè)成員，分別來(lái)自A,、B和D基因組,，據(jù)此將9個(gè)基因分別命名為T(mén)aHsp90.1-A1、B1,、D1,，TaHsp90.2-A1、B1,、D1和TaHsp90.3-A1,、B1、D1,。同時(shí),，通過(guò)同源克隆方法獲得了普通小麥A基因組的二倍體供體種烏拉爾圖小麥（T. urartu，AA）,、D基因組的二倍體供體種粗山羊草（Ae. tauschii，DD）和四倍體的野生二粒小麥（T. turgidum ssp. dicoccoides,，AABB）中的全部12個(gè)同源基因,。
進(jìn)化分析顯示，Hsp90.2和Hsp90.3兩組基因的親緣關(guān)系較近，在進(jìn)化樹(shù)中處于一個(gè)分枝,，而Hsp90.1與其它兩組Hsp90基因的親緣關(guān)系相對(duì)較遠(yuǎn),，單獨(dú)處于一個(gè)分枝。暗示3組胞質(zhì)Hsp90可能已經(jīng)產(chǎn)生了功能分化,。隨后,，利用病毒誘導(dǎo)的基因沉默（VIGS）實(shí)驗(yàn)對(duì)3組Hsp90基因的功能進(jìn)行了分析。結(jié)果表明,，降低TaHsp90.1基因的表達(dá)后,，小麥植株發(fā)育明顯遲緩，而部分沉默其它兩組基因?qū)χ仓晟L(zhǎng)發(fā)育無(wú)明顯影響,，說(shuō)明TaHsp90.1是小麥正常生長(zhǎng)發(fā)育所必需的,。對(duì)通過(guò)VIGS分別降低了3組TaHsp90基因表達(dá)的抗條銹病小麥品種Suwon11植株接種小麥條銹菌小種Cy29，結(jié)果發(fā)現(xiàn)降低TaHsp90.2或TaHsp90.3表達(dá)的植株對(duì)條銹菌的抗性（HR）喪失,，淪為感病,，而降低TaHsp90.1表達(dá)的植株仍然保持對(duì)Cy29的良好抗性。說(shuō)明TaHsp90.2和TaHsp90.3兩組基因具有抗小麥條銹病功能,。
該研究首次揭示了小麥胞質(zhì)Hsp90基因家族內(nèi)部的功能分化,，并證實(shí)了不同組的基因分別具有調(diào)控生長(zhǎng)發(fā)育或抗條銹病功能。
該研究結(jié)果已于4月13日在《新植物學(xué)家》（New Phytologist）上在線發(fā)表,。張相岐實(shí)驗(yàn)室的博士研究生王官鋒和魏學(xué)寧為該論文的共同第一作者,，張相岐研究員和王道文研究員為共同通訊作者。該研究得到了國(guó)家“轉(zhuǎn)基因生物新品種培育”科技重大專(zhuān)項(xiàng)的資助,。（生物谷Bioon.com）
生物谷推薦原文出處：
New Phytologist DOI： 10.1111/j.1469-8137.2011.03715.x
Molecular analysis of common wheat genes encoding three types of cytosolic heat shock protein 90 (Hsp90): functional involvement of cytosolic Hsp90s in the control of wheat seedling growth and disease resistance
Wang, Guan Feng; Wei, Xuening; Fan, Renchun; Zhou, Huanbin; Wang, Xianping; Yu, Chunmei; Dong, Lingli; Dong, Zhenying; Wang, Xiaojie; Kang, Zhensheng; Ling, Hongqing; Shen, Qian Hua; Wang, Daowen; Zhang, Xiangqi
Heat shock protein 90 (Hsp90) molecular chaperones play important roles in plant growth and responses to environmental stimuli. However, little is known about the genes encoding Hsp90s in common wheat. Here, we report genetic and functional analysis of the genes specifying cytosolic Hsp90s in this species.?Three groups of homoeologous genes (TaHsp90.1, TaHsp90.2 and TaHsp90.3), encoding three types of cytosolic Hsp90, were isolated. The loci containing TaHsp90.1, TaHsp90.2 and TaHsp90.3 genes were assigned to groups 2, 7 and 5 chromosomes, respectively. TaHsp90.1 genes exhibited higher transcript levels in the stamen than in the leaf, root and culm. TaHsp90.2 and TaHsp90.3 genes were more ubiquitously transcribed in the vegetative and reproductive organs examined.?Decreasing the expression of TaHsp90.1 genes through virus-induced gene silencing (VIGS) caused pronounced inhibition of wheat seedling growth, whereas the suppression of TaHsp90.2 or TaHsp90.3 genes via VIGS compromised the hypersensitive resistance response of the wheat variety Suwon 11 to stripe rust fungus.?Our work represents the first systematic determination of wheat genes encoding cytosolic Hsp90s, and provides useful evidence for the functional involvement of cytosolic Hsp90s in the control of seedling growth and disease resistance in common wheat.
