Enhanced Tolerance to Water Deficit and Salinity Stress in Transgenic Lycium barbarum L. Plants Ectopically Expressing ATHK1, an Arabidopsis thaliana Histidine Kinase Gene

ATHK1 has been implicated in drought and salt tolerance in Arabidopsis thaliana. In this study, the full-length coding sequence of ATHK1 was introduced into Lycium barbarum L. by Agrobacterium transformation. Our results indicated that the transgenic plants tolerated high concentrations of NaCl or water deprivation and exhibited faster recovery following re-watering compared to wild type plants. Salt- or water-stressed transgenic plants had higher relative water content, proline and soluble protein levels, and lower chlorophyll losses and membrane ion leakage. In addition, they showed higher capacity for antioxidative reactions reflected by reduced hydrogen peroxide (H2O2), superoxide anion radical (O-2 (-)), and lipid peroxide production and increased superoxide dismutase, catalase, and peroxidase activities. The ATHK1 transcript, as shown by reverse transcription polymerase chain reaction, was more abundant under high than low osmolarity in transgenic plants. ATHK1 therefore improved tolerance of L. barbarum to drought and salt stress.