Transcriptional Expression of the StSnRK2 Gene Family in Response to Osmotic Stress and Correlation Analysis Between Physiological Traits

Sucrose non-fermenting-1 related protein kinases 2 (SnRK2) is a family of highly conserved plant protein kinases. They play important roles in abscisic acid-dependent plant development, and are involved in the stress responses of plants to osmotic stress caused by drought and salinity. In the current study, the transcriptional expression of StSnRK2genes from tetraploid potato (Solanum tuberosum L. cv.‘Longshu No.3’) plantlets in response to gradient saline stress (0, 25, 50, 100 and 200 mmol/L NaCl) and gradient water stress (0, 2%, 4%, 6% and 8% PEG) were determined over three continuous observations (two, four, and six weeks, respectively). Results showed that the expression pattern of StSnRK2 varied under salt and drought stresses. The transcripts of StSnRK2.4and StSnRK2.6 increased under saline treatment, whereas StSnRK2.3 increased with PEG treatment. The transcriptional expression of StSnRK2.5 decreased under saline treatment, but increased under PEG treatment. Under saline treatment, the expression of StSnRK2.6 was positively correlated with the activity of CAT and SOD, and negatively correlated with stomatal area. Under PEG treatment, the StSnRK2.6 transcripts were positively correlated with proline content. Results from this study will offer valuable reference for the molecular breeding of stress resistant potato varieties.