Abstract
摘要:植物在生長過程常遭受各種生物性及非生物性逆境,農作物產量也因逆境而造成巨大損失,全球為解決此問題而採取的作法對生態系統也造成了不可避免的傷害。事實上,植物為了存活於自然界中各種嚴苛的環境,已經發展出不同的防禦機制。因此,研究植物的防禦機制並將之應用於農業上,將發展永續農業,並得以保護生態系統。番茄青枯病是全球最嚴重的病害之一,但我們對於植物如何抵抗這類土壤傳播病的防禦機制了解仍極少。Ethylene-responsive element binding factors (ERFs)是植物特有的轉錄因子,在植物的逆境訊息傳遞反應中扮演中樞角色,因此,了解ERFs如何調控植物在逆境下的反應當然是重要且必需的。藉由微陣列分析技術,我們已在阿拉伯芥中找到一個會在青枯病菌感染時快速被誘導表現的未知功能的基因At5g61600;另外,利用virus-induced gene silencing (VIGS)的方法,我們也證實番茄中的兩個ERF基因(LeERF3 和TRSF)參與抗青枯病的防禦反應中。為了進一步研究相關的植物防禦機制,在此計畫中,我們將會針對At5g61600和特定的番茄ERF基因進行功能性分析,預計進行一系列的研究,包括:在不同時間點及不同部位的表現情況、在細胞內的表現位置、利用transient/transgenic overexpression與knock-out/down等方法來證實不同的ERFs在植物青枯病防禦機制中的角色、以transcriptomic策略分析受其調控之目標基因。此外,由於青枯病與缺水逆境有許多共通點,我們也將透過與其他子計畫的合作,同時研究這些ERFs在植物缺水逆境中所扮演的角色。另外,由於我們已經建立了完善的青枯病的分析系統,本子計畫也可協助其他子計畫,分析其研究之目標基因是否在植物青枯病反應中扮演重要角色。透過整體研究計畫的整合,本子計畫預期將在植物對抗疾病與缺水逆境防禦機制上提供重要資訊,並期望可集結有利於農作物生物科技發展之資源。
Abstract: Plant constantly encounters environmental stresses, including abiotic and biotic factors. The huge amount of agricultural efforts devoted to reduce the tremendous losses in crop productivity due to stresses has led to irreversible harm to our ecosystems. In nature, most plants possess various defensive machineries to ensure their survival in harsh environments. Therefore, elucidation of plant nature defense mechanisms and explore their potential applications on improvement of crop stress tolerance would serve as a useful strategy for agriculture sustainability and thus benefit protection of our ecosystems. Tomato bacterial wilt (BW) is one of the most complex and serious crop diseases worldwide. However, information on plant defense response to systemic infection of soil-borne pathogens is very limited. ERFs (ethylene-responsive element binding factors) are plant-specific transcription factors, playing a pivotal role in plant signaling transduction pathways switching extracellular signals into cellular responses, including biotic and abiotic stress responses. A better understanding about how these proteins regulate plant stress responses is thus important and would be highly desired. By carrying out transcriptomic analysis using a micoarray approach, we have identified an early BW-responsive ERF gene of unknown function, At5g61600. In addition, using a virus-induced gene silencing (VIGS) approach, we have also evidenced that two tomato ERF genes, LeERF3 and TRSF, are involved in natural defense response against BW. To elucidate plant defense mechanism further, this sub-project will study functions of At5g61600 and tomato ERF genes (B1a and B3 clusters) in plant disease defense, and gain insights into the involved mechanisms. Spatial/temporal gene expression and sub-cellular localization of the ERF gene products will be analyzed. Transient and transgenic knock-out/down and overexpression approaches will be employed to determine the authentic roles of the studied genes in plant defense mechanism. Target genes of selected ERFs will be identified by taking transcriptomic approaches. Furthermore, as the nature of BW shares commonness with that of water deficit (WD), roles of the studied ERFs in plant responses to drought and salinity will be investigated as well through coordination with other sub-projects. Additionally, with the well-established BW-bioassay systems, this sub-project could provide assistance to determine whether the genes proposed to be studied in other sub-projects involve in plant response to BW. Through the integration of this Programmatic Project, the functional genomic studies proposed here are expected to gather important information about plant defense mechanisms against important diseases and water deficit, as well as to assemble resources useful for crop biotechnology.
Keyword(s)
阿拉伯芥
番茄
ERF
青枯病
缺水
防禦
Arabidopsis
tomato
ERF
bacterial wilt
water deficit
defense