Isolation and functional characterization of the ASR gene from Ipomoea pes-caprae

We focused on the full-length cDNA encoding ASR protein isolated from a Ipomoea pes-caprae (Linn.) Sweet. cDNA library. Results showed the coding region of IpASR cDNA was 648 bp, encoding a 215 amino acid protein with a molecular weight of 24.57 kD and isoelectric point of 5.42. By ectopic expression of IpASR in yeast, we found that IpASR improved the salt and H₂O₂ tolerance of transgenic yeast strains. Using adult plants and seedlings of I. pes-caprae with or without abiotic stress and ABA treatment, real-time RT-PCR analysis showed that IpASR was widely expressed in different adult organs in I. pes-caprae. The IpASR transcript was induced under abiotic stress and ABA treatment. The subcellular localization assay combining bioinformatics analysis showed that IpASR was a nucleoprotein. These results suggest that IpASR might play an important role in the regulation of I. pes-caprae growth and development, and therefore respond to environmental abiotic stress and the ABA signal pathway.