Abstract:

【Objective】 CTR1 is a key negative regulator in ethylene signal transduction. A salt-induced CTR1 like gene (TaCTR1)was cloned from wheat, the expression of TaCTR1 under abiotic stresses and ABA treatment, the subcellular localization and the effect of overexpression of TaCTR1 on salt tolerance in tobacco was studied. 【Method】 A putative CTR1 gene was cloned and characterized from wheat via rapid amplification of cDNA ends ( RACE) and RT-PCR, TaCTR1 expression under stresses was analyzed using semi-quantitative RT-PCR, and the effect of overexpression of TaCTR1 on salt tolerance was conducted in tobacco.【Result】 The full-length cDNA of TaCTR1 is 2 635 bp which codes for a polypeptide of 759 amino acids. There is a conserved serine/threonine protein kinase domain at the carboxyl terminus containing an ATP-binding site. Southern analysis revealed that TaCTR1 is consisted of a gene family in wheat. The amino acid homologies of CTR1 among different organisms share higher similarities. Expression analysis revealed that TaCTR1 was induced by NaCl and drought stress but inhibited by ABA treatment. Transient expression of TaCTR1:GFP in the onion epidermal cells revealed that TaCTR1 was probably localized to the plasma membrane. Over expressing TaCTR1 decreased salt tolerance of transgenic tobacco (Nicotiana tabacum L.) plants compared with control. 【Conclusion】 TaCTR1 is the first CTR1 gene cloned in wheat and may involve in various abiotic stresses. Overexpression of TaCTR1 decreased the salt-tolerance in tobacco suggested that TaCTR1 may act as a negative regulator of salt stress in plants.

Key words: CTR1, RACE, stress, Triticum aestivum L, transgenic tobacco