Alternatively spliced transcripts of group 3 late embryogenesis abundant protein from Pogonatherum paniceum confer different abiotic stress tolerance in Escherichia coli

The gene encoding a group 3 late embryogenesis abundant (LEA) protein was cloned from callus of the drought-tolerant grass Pogonatherum paniceum. Three alternatively spliced transcripts of this gene were amplified by RT-PCR. According to the bioinformatics analysis, the gene contained three exons and two introns. The PpLEA3.1 transcript which was the most abundant one in P. paniceum contained all three exons, and the PpLEA3.2 transcript lacked fragments of the first two exons which encoded a 41-amino acid-long region of the PpLEA3 protein. The PpLEA3.3 transcript retained the second intron. The three splicing patterns resulted in changes in the number of repeats of an 11-amino acid motif, hydropathy and the predicted 3-dimensional structure. When expressed in Escherichia coli, the three proteins differentially affected growth responses to salt, cold and heat stress. These results confirmed that the complete motif repeat structures and an appropriate hydrophilic/hydrophobic balance are important for the LEA protein in providing protection against various forms of stresses.