Role of the Phyllostachys edulis SnRK1a gene in plant growth and stress tolerance

Abstract

Sucrose nonfermenting 1 (SNF1)-related protein kinase 1 (SnRK1) plays a crucial role in carbon metabolism and stress responses in annual herbaceous plants. However, the function of SnRK1 in perennial gramineous bamboo is unclear. Here, a SnRK1 gene was isolated from Phyllostachys edulis and named PeSnRK1a. Sequence analysis indicated that the open reading frame (ORF) of PeSnRK1a comprised 1509 nucleotides encoding 502 amino acids that composed typical N-terminal Ser/Thr-protein kinase catalytic (STKc), ubiquitin-associated (UBA) and kinase-associated 1 (KA1) domains. Amino acid sequence alignment showed that PeSnRK1a shares 83–92% identity with Arabidopsis thaliana, Sorghum bicolor, Zea mays and Oryza sativa homologs. Phylogenetic analysis suggested that PeSnRK1a is homologous to ZmSnRK1a, SbSnRK1a and OSK1 (a SnRK1a gene in rice) and belongs to the SnRK1a subfamily. On the basis of the results of real-time quantitative PCR analysis, PeSnRK1a was more highly expressed in the leaves than in the roots and stems. Abiotic stress (200 mM NaCl and darkness) induced the expression of PeSnRK1a in Phyllostachys edulis seedlings. Compared with wild-type (WT) seeds, transgenic PeSnRK1a-overexpressing seeds presented a significantly greater germination rate under high-salt conditions, and the transgenic seedlings had longer roots. Additionally, the transgenic leaves experienced slower senescence than did the WT leaves under darkness. These results suggest that PeSnRK1a plays an important regulatory role in bamboo development and stress tolerance.