Functional analysis of a salt-and water deficit-induced AP2 transcription factor in Arabidopsis

• Main Authors: MEI-HSIU LIN, 林美秀
• Other Authors: MING-TSAIR CHAN
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/35519966424857374845

碩士 === 國立中央大學 === 生命科學研究所 === 93 === Abstract Plants are exposed to dynamic environmental stresses throughout their life cycle. Drought, low temperature and high salts in the soils are the most common stresses that alter metabolism and gene expression, which affects agricultural productivity. Although these stresses are quite different they do induce similar or different genes in order to cope with changes in the environment. The predominant mechanism for controlling gene expression in plants is regulated at transcriptional level and is mediated by transcription factors, which active or represses transcription. The AP2/EREBP is a gene family encodes transcription factors with highly conserved AP2-binding domain and is unique to plants. Some of AP2/EREBP family genes such as CBF1, AP2 and EREBP etc., have been characterized as key regulators in developmental processes and biotic or abiotic stresses. Recently we have isolated a novel AP2/EREBP transcription factor induced by drought and salt stresses from Affymetrix microarray. The northern blot data revealed that expression of AF9 (At4g34410) was induced under salt stress and drought stress. However, expression under drought stress is not clear and this data need to be confirmed. In addition, AF9 was also induced by H2O2, MV, Cd, Cu, ethylene, and methyl jasmonate. Furthermore, it was induced in early phase of stresses. A binary vector consisting of AF9 gene was transferred to Arabidopsis via A. tumefaciens. Four T0 transgenic lines were obtained and collected T1 progeny. The leaves of T1 transgenic plants are more with many short hairy roots than wild-type. It was demonstrated that AF9 protein can bind to the GCC box (-AGCCGCCAC-) in promoter of responsive gene by EMSA. Moreover, two proteins, At1g65720 and At5g18970 were identified by bacterial two hybrid screening and confirmed by yeast two hybrid screening. These two genes were co-bombarded into onion epidermis to confirm the interaction with AF9. These results could help us to understand the function of AF9 gene in plants for further studies.