Characterization of OsLEA1a and its inhibitory effect on the resistance of E. coli to diverse abiotic stresses.

OsLEA1a is a late embryogenesis abundant (LEA) protein gene from Oryza sativa L, which contains an open reading frame of 282-bp that encodes a putative polypeptide of 93 amino acids. OsLEA1a protein contains abundant of Lys, Ala, Glu, Asp, Gly, Arg and Leu, but depleted in Cys, His, Phe, Trp and Tyr residues; and is strongly hydrophilic. OsLEA1a includes six helical domains and a β-sheet domain. Real-time PCR analysis showed that OsLEA1a was expressed in roots, leaves and panicles of rice, with no or only a few transcripts in stem tissues, and remained at a relatively higher level in leaves during the tillering period, the heading period, the filling period and the full ripe period. To make sense of OsLEA1a functions, TrxA-OsLEA1a fusion protein expression vector and OsLEA1a protein expression vector were transformed into Escherichia coli DL21 (DE3), respectively. The accumulation of the TrxA-OsLEA1a fusion protein or OsLEA1a protein interfered with the resistance of E. coli to high salinity, metal ions, hyperosmotic, oxidation, heat and freeze-thaw stresses. The purified TrxA-OsLEA1a fusion protein reduced stabilization of LDH and increased damage of diverse abiotic stresses to LDH. The findings suggested that the OsLEA1a may confor antibacterial activity under abiotic stresses.