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棉 花 学 报 Cotton Science 2008,20(2):88-93
Molecular Cloning and Expression Analysis of Two Chitinase in Upland Cotton Abstract: ESTs encoding class Ⅲ and class Ⅳ chitinase respectively were isolated from the SSH library inoculated with Verticillium wilt. Both of them contained full 3 ' end and their full open reading frame were obtained by RACE and RT-PCR. As a result, the entire coding region of class Ⅲ and class Ⅳ chitinase is 1390 bp and 678 bp respectively and encodes a polypeptide of 298 and 226 amino acids. The polypeptide encoded by these two genes shared 71% and 65% homology to their homologous proteins of Arabidopsis . They were designated as Ghachi 3 and Ghachi 4. All of these two genes have signal peptide and were predicted to be extracellular chitinase. Ghachi 3 were abundant in petals, buds and phloem, whereas Ghachi 4 only showed an extremely high level in phloem by semi-quantitative RT-PCR. The accumulation of Ghachi 4 increased remarkably after treatment of Verticillium wilt and Fusarium wilt in the disease resistant cultivar exclusively. But Ghachi 3 was also induced by Verticillium wilt in the susceptible cultivar. In addition, the expression of both the two genes increased remarkably after treatment of ABA. All the results indicated that these two genes might play roles in response to biotic and abiotic stresses.
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