Characterization of OsPM19L1 encoding an AWPM-19-like family protein that is dramatically induced by osmotic stress in rice.

The plant-specific AWPM-19-domain proteins play important roles in plant development and stress responses. In the current study, OsPM19L1 encoding Oryza sativa AWPM-19-like protein 1 was isolated from rice. Tissue-specific gene expression analysis revealed that OsPM19L1 was highly expressed in the leaf sheath of rice. Interestingly, expression of OsPM19L1 was high at the early stage of panicle development and decreased thereafter. qRT-PCR analysis indicated that OsPM19L1 was dramatically induced by 20% PEG stress (>600-fold), exogenous abscisic acid (>350-fold), salt and cold stress. Subcellular localization assay suggested that the OsPM19L1-GFP (green fluorescent protein) fusion protein was localized in the membrane system in rice cells. Moreover, under stress conditions, OsPM19L1 expression was enhanced in an ABI5-Like1 (ABL1) deficiency rice mutant, abl1, suggesting that ABL1 negatively regulates OsPM19L1 gene expression. Thus, OsPM19L1 appears to be closely associated with stress tolerance through ABA-dependent pathway in rice.