Roles of tomato ERF cluster B1-a in response to bacterial wilt and abiotic stress responses
Date Issued
2011
Date
2011
Author(s)
Yang, Tsung-Lin
Abstract
Plants constantly encounter a wide range of abiotic and biotic stresses, leading to tremendous crop losses. Plant bacterial wilt (BW), a serious vascular disease caused by Ralstonia solanacearum (Rs), is one of the most complex and serious crop diseases worldwide. However, information on plant defense response to systemic soil-borne diseases is very limited. Ethylene-response factors (ERFs) are a subfamily of the APETALA2 (AP2)/ethylene-responsive-element-binding protein (EREBP) transcription factor superfamily and unique to plants. ERFs play a pivotal role in plant signaling transduction pathways switching extracellular signals into cellular responses. In this study, roles of five uncharacterized members of tomato ERF cluster B1-a, namely SlERF B1a-1,-2,-3,-4,-5, in plant response to BW and water deficit (WD) are investigated. These ERFs localize in nucleus and confer transcriptional repression activity. These genes display differential transcriptional expression patterns in various tissues and under, treatments of Rs, drought and defense phytohormones, implying they may have distinct functions. VIGS assays further revealed their differential roles in tomato defense to BW and water deficit (WD) response. Results of functional analyses by VIGS and transgenic overexpression suggest that SlERF B1a-1 may play a positive role in defense to BW and salinity, and a negative role in drought. However, SlERF B1a-3 may play a negative role in defense response to BW and drought, and a positive role in salinity. Furthermore, functioning of these two genes involves ET/JA (ethylene/ jasmonic acid)-related pathways. On the other hand, reduced seed germination rates of Arabidopsis at5g44210 null mutants, an othorlogous gene of SlERF B1a-1, indicated a function of this gene in various abiotic stresses. However, mature plants of the null mutants displayed unaltered response to Rs, Pectobacterium chrysanthemi and drought treatments. Together, these results demonstrate important overlapping and differential roles of the studied ERF cluster B1-a members in plant response to biotic and abiotic stresses. These studies, along with further suggested analyses, are expected to decipher multiple functions of these proteins and to establish the related regulatory networks in plant stress responses.
Subjects
Ethylene-response factors (ERFs)
bacterial wilt (BW)
water deficit (WD)
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