Enhanced tolerance against heat stress of Escherichia coli cells by overexpressing an Ammopiptanthus mongolicus heat stress associated protein gene AmHsa32.

The extremely summer high temperature in desert region makes the plant heat tolerant and a desirable model for revealing the mechanism of plant resistance to heat stress. In the present research, one gene designated as AmHsa32 encoding heat stress associated protein 32 was cloned by expressed sequence tags from cold and droughttreated Ammopiptanthus mongolicus seedlings. Bioinformatic analysis showed that the ORF of AmHsa32 was composed of 858 base pairs, which encoded a heat stress associated protein with 286 amino acids and a molecular weight of 32 kD. AmHsa32 had a high affinity with heat stress associated protein 32 in Arabidopsis thaliana. qRTPCR analysis showed that the expression level of AmHsa32 was 25fold of control one hour later under heat stress and upregulated under cold，drought，and salt stresses. Escherichia coli cells expressing AmHsa32 protein showed increased resistance to heat stress(50 ℃) compared with control. We propose that AmHsa32 plays a protective role in cells under heat stress. This finding could potentially be used to improve the plant tolerance to heat stress via gene transfer.