Molecular Cloning of a Cotton Phosphatase Gene and Its Functional Characterization

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Shi-You Lu¹, Guang-Rong Zhao¹, Ai-Min Wu¹, M. A. Jenks², Shuping Zhang¹, and Jin-Yuan Liu^1*

¹Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, China; E-mail: liujy@mail.tsinghua.edu.cn

²Department of Horticulture and Landscape Architecture, Center for Plant Environmental Stress Physiology, Purdue University, West Lafayette, IN 47907, USA

^* To whom correspondence should be addressed.

Received February 19, 2009; Revision received April 22, 2009

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In this study, we report isolation of a phosphatase gene designated GhHL1 from cotton and its functional characterization. GhHL1 transcripts were detected in all cotton tissues examined. Southern blotting analysis indicated that it exists in multiple-copies. Biochemical analysis showed that GhHL1 was Mg²⁺-dependent and cation-sensitive. Purified recombinant GhHL1 protein dephosphorylated both 3′,5′-bisphosphate nucleotide and inositol 1,4-bisphosphate, demonstrating dual 3′,5′-bisphosphate nucleotidase and inositol polyphosphate 1-phosphatase activities. Overexpression of GhHL1 complemented yeast hal2 mutant and enhanced yeast growth under elevated NaCl or LiCl, showing a role in salt tolerance associated with ionic stress response. Taken together, these results show that GhHL1 is a functional and good candidate gene, which might be used to improve salt tolerance in plants.

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KEY WORDS: cotton, phosphatase, salt tolerance, enzyme activity, functional characterization

DOI: 10.1134/S0006297910010116

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