我國(guó)人口眾多,，保障糧食生產(chǎn)安全顯得更加重要。糧食生產(chǎn)高度依賴于水資源,，而水資源瀕乏嚴(yán)重制約糧食生產(chǎn)安全,。在世界經(jīng)濟(jì)的發(fā)展特別是發(fā)展中國(guó)家的發(fā)展對(duì)水資源的需求日趨增加，缺水的情況逐漸加劇的情況下,，一方面不斷提高水資源管理水平提高糧食生產(chǎn),，另一方面利用生物技術(shù)手段特別是轉(zhuǎn)基因技術(shù)育種有效地提高農(nóng)作物抗干旱和抗鹽堿能力，為我國(guó)糧食生產(chǎn)提供有力的保障,，已經(jīng)成為了一個(gè)重要的關(guān)鍵技術(shù),。在農(nóng)作物轉(zhuǎn)基因技術(shù)日趨成熟背景下，挖掘行之有效地抗干旱基因是農(nóng)業(yè)生物技術(shù)發(fā)展迫切需求,。中科院版納植物園功能基因研究組余迪求研究員領(lǐng)導(dǎo)的研究小組從水稻逆境誘導(dǎo)的cDNA文庫(kù)中克隆獲得一個(gè)能有效調(diào)控植物抗干旱和鹽堿能力的轉(zhuǎn)錄調(diào)節(jié)基因WRKY45,。表達(dá)譜分析表明，OsWRKY45受干旱,、鹽堿,、病源菌等多種逆境因子，以及非生物逆境調(diào)控激素脫落酸（ABA）處理而強(qiáng)烈誘導(dǎo)表達(dá)。在轉(zhuǎn)基因擬南芥中過(guò)量表達(dá)OsWRKY45可以激活植物抗病相關(guān)基因PRs的表達(dá),，從而提高植物對(duì)病原菌的抗性,。另一方面，該基因也能有效地提高轉(zhuǎn)基因植物對(duì)高鹽及干旱的耐性,，同時(shí)減弱了轉(zhuǎn)基因植物在萌發(fā)階段及其后期的幼苗生長(zhǎng)階段對(duì)ABA的敏感性,，一些逆境相關(guān)基因及ABA合成基因的表達(dá)也有所增強(qiáng)。進(jìn)一步研究證實(shí),，OsWRKY45也能有效地提高轉(zhuǎn)基因水稻抗干旱能力,。這揭示了OsWRKY45可以提高多種植物抗干旱能力，具有廣泛的應(yīng)用前途,。
一般而言,，如果一個(gè)基因能夠有效地提高轉(zhuǎn)基因植株對(duì)逆境的抗性水平，那么該基因必定會(huì)降低轉(zhuǎn)基因植物的生物量,，從而導(dǎo)致產(chǎn)量降低,。然而OsWRKY45基因就表現(xiàn)出不同的特征，在水稻和擬南芥中高表達(dá)該基因后不僅能有效地提高轉(zhuǎn)基因植株抗干旱能力,，而且不會(huì)引起任何轉(zhuǎn)基因植物在其形態(tài)發(fā)生,、花器官發(fā)育、授粉特征,、結(jié)實(shí)率及最終產(chǎn)量等指標(biāo)沒(méi)有任何降低,，相反還有一定程度的改善。
相關(guān)研究結(jié)果發(fā)表在愛(ài)思唯爾期刊《環(huán)境與實(shí)驗(yàn)植物學(xué)》（Environmental and Experimental Botany）上,。（生物谷Bioon.com）
生物谷推薦原始出處：
Environmental and Experimental Botany,，doi:10.1016/j.envexpbot.2008.07.002，Yuping Qiu,，Diqiu Yu
Over-expression of the stress-induced OsWRKY45 enhances disease resistance and drought tolerance in Arabidopsis
Yuping Qiua, b and Diqiu Yua, ,
aXishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming 650223, PR China
bGraduate School of the Chinese Academy of Sciences, Beijing 100039, PR China
Abstract
The WRKY transcriptional factor superfamily regulates diverse functions, including processes such as plant development and stress response. In this study, we have shown that the rice WRKY45 (OsWRKY45) expression is markedly induced in response to stress-related hormone abscisic acid (ABA) and various stress factors, e.g., application of NaCl, PEG, mannitol or dehydration, treatment with 0 °C and 42 °C as well as infection by Pyricularia oryzae Cav. and Xanthomonas oryzae pv. oryzae. Together, these results indicate that the OsWRKY45 may be involved in the signal pathways of both biotic and abiotic stress response. Further analyses of 35S:OsWRK45 Arabidopsis plants have shown that ectopic, constitutive over-expression of the OsWRKY45 transgene confers a number of properties to transgenic plants. These properties include significantly increased expression of PR genes, enhanced resistance to the bacterial pathogen Pseudomonas syringae tomato DC3000, enhanced tolerance to salt and drought stresses, decreased sensitivity toward ABA signalling during seed germination and post-germination processes, and modulation of ABA/stress-regulated genes during drought induction. In addition, higher levels of OsWRKY45 expression in transgenic plants correlate positively with the strength of the abiotic and biotic responses mentioned above. More specifically, the decreased ABA sensitivities, the enhanced disease resistance and drought tolerances may be attributed, in part, to stomatal closure and induction of stress-related genes during drought induction. The relationship between OsWRKY45 expression and ABA signalling is discussed.
