Arabidopsis LOS5 Gene Enhances Chilling and Salt Stress Tolerance in Cucumber
2013
LIU Li-ying, DUAN Liu-sheng, ZHANG Jia-chang, MI Guo-quan, ZHANG Xiao-lan, ZHANG Zhen-xian, REN Hua-zhong (1.Key Laboratory for Bio-Resource and Eco-Environment, Ministry of Education/State Key Laboratory of Hydraulics and Mountain River Engineering/College of Life Science, Sichuan University, Chengdu 610064, P.R.China 2.Neijiang Hybrid Rice Research and Development Center, Neijiang 641000, P.R.China 3.Department of Plant, Soil and Entomological Sciences, University of Idaho, Moscow 83844, USA 4.School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, P.R.China)
Low temperature and high salinity are the major abiotic stresses that restrict cucumber growth and production, breeding materials with multiple abiotic resistance are in greatly need. Here we investigated the effect of introducing the LOS5 gene, a key regulator of ABA biosynthesis in Arabidopsis thaliana, under the stress-responsive RD29A promoter into cucumber (Cucumis sativus L. cv. S516). We found that T1 RD29A-LOS5 transgenic lines have enhanced tolerance to cold and salt stresses. Specifically, transgenic lines exhibited dwarf phenotypes with reduced leaf number, shorter internode, decreased length of the biggest leaf, fewer female flowers, shorter fruit neck and lower vitamin C (Vc). The increased cold tolerance can be reflected from the significantly decreased cold index, the reduced electrolyte leakage index and the MDA content upon cold treatment as compared to those in the control. This may result from the accumulation of internal ABA, soluble sugars and proline, and the enhanced activities of protective enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the transgenic lines. Under salt treatment, the transgenic lines exhibited increased germination index, vigor index, more lateral roots and increased root fresh weight. Moreover, RD29A-LOS5 transgenic plants displayed quicker responses in salt stress than that in low-temperature stress.
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