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Study of Solanaceae zinc finger protein and EAS genes in disease and abiotic stress responses
Date Issued
2011
Date
2011
Author(s)
Chen, Ya-Ting
Abstract
Plant constantly encounters environmental stresses, including biotic and abiotic factors. Bacterial wilt (BW, caused by Ralstonia solanacearum or Rs) and water deficit (WD) are very important factors limiting crop production worldwide. The aim of this work was to study function of a tomato zinc-finger protein SlZFP (a C3HC4-RING finger protein) and a Solanaceae gene encoding 5-epi-aristolochene synthase (EAS) in biotic and abiotic stresses. Previously, SlZFP was suggested to involve in tomato BW defense mechanism by virus-induced gene silencing (VIGS). This study further revealed that SlZFP was abundantly expressed in tomato flower and mature fruit, and that GFP::SlZFP recombinant protein localized on cytoskeleton in Arabidopsis protoplasts. SlZFP expression at transcriptional level was suppressed by Rs and various pathogen-associated molecular patterns (PAMPs), but not significantly changed under drought and phytohormone treatments. In addition, VIGS of SlZFP in tomato resulted in increased sensitivity to drought stress, and the 35S::SlZFP transgenic tobacco displayed enhanced tolerance to BW, drought, oxidative stress and salinity. Furthermore, expression of SA-dependent pathway-related genes was enhanced in 35S::SlZFP transgenic tobacco under normal growth condition. These results together evidences an important and positive role of SlZFP in defense response to multiple stresses. On the other hand, null mutants of the Arabidopsis orthologous gene At5g24870 of SlZFP exhibited significantly increased susceptibility to various abiotic stresses during seed germination stage, but their response to Rs and Pectobacterium chrysanthemi infection was not obviously affected, suggesting that At5g24870 is involved in plant defense to various abiotic stresses. Secondly, tomato SlEAS was suggested to involve in tomato BW defense mechanism by VIGS. Current study further showed that 35S::NtEAS transgenic tobacco conferred enhanced tolerance to BW, oxidative and salinity, and that expression of SA-dependent pathway-related genes in these transgenic plants was enhanced under normal growth condition. In addition, our previous study identified and isolated a Nicotiana glutinosa EAS (NgEAS) whose expresion could be significantly induced by Rs and oxidative stress. This study further revealed that NgEAS promoter can be systemically induced by a group of economically important phytopathogenic bacteria and fungi, as well as PAMP in vascular tissues, and the GT-1 box is an essential cis-element for systemic activation. These results consistently demonstrate that Solanaceae EAS positively regulate defense response to microbial pathogens and various abiotic streses. Collectively, current study paves the way not only for elucidating mechanisms and determinants involved in plant stress defense responses, but also for potentially the establishing useful means of breeding crops with enhanced tolerance to diseases and abiotic stresses.
Subjects
Zinc finger protein
Ralstonia solanacearum
drought
5-epi-aristolochene
inducible promoter
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ntu-100-R97b42034-1.pdf
Size
23.32 KB
Format
Adobe PDF
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