Cloning and abiotic stress resistance analyses of a new proline-glycine-alanine histidine-rich protein gene from Ipomoea batatas (L.) Lam.

Authors: XIANG TAO, BIN YONG, HUAN-HUAN SHAO, XIN-RONG MA

Abstract: Sweet potato [Ipomoea batatas (L.) Lam.] is one of the top six most important crops in the world in terms of production. It has the capacity to tolerate marginal growing conditions better than most other crops. In this study, a proline- and glycine-rich protein encoding gene, IbPGAHRP1, was isolated and characterized from the transcriptome of sweet potato cultivar Xushu 18. Sequence analyses showed that proline, glycine, alanine, and histidine account for 62.6% of the total amino acid residues. Two proline-rich tandem repeats, an alanine-rich repeat, a histidine-rich tandem repeat, and five XYPP motifs were present in IbPGAHRP1. Sequence similarity analysis showed that IbPGAHRP1 shared 41% similarity with GmGPRP4, indicating that IbPGAHRP1 should be a GPRP-like protein and play an important role in stress resistance. RT-PCR results showed that IbPGAHRP1 was specifically expressed in the sweet potato flower. In vivo expression of IbPGAHRP1 demonstrated that it enhanced the cold and drought resistance in the yeast recombinant, but could not trigger the same changes in Escherichia coli. This study revealed that IbPGAHRP1 is a flower-specific gene and should play an important role in response to abiotic stresses.

Keywords: Flower-specific, IbPGAHRP1, sweet potato, abiotic stress

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