Role of glucose-6-phosphate dehydrogenase in the drought tolerance of alfalfa

doi:10.11686/cyxb2017308

Abstract

Abstract: Glucose-6-phosphate dehydrogenase (G6PDH, EC1.1.1.49) is the first and critical rate-limiting enzyme in the pentose phosphate pathway. It is involved in the synthesis of NADPH and ribose-5-phosphate, and plays an important role in plant responses to biotic and abiotic stresses. The aim of this study was to explore the role of G6PDH under drought stress in alfalfa. First, 7-day-old alfalfa seedlings were treated with different concentrations of polyethylene glycol (PEG), and then plant height and root length, fresh weight and dry weight, and the contents of hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) were determined. These analyses were used to define the concentration of PEG causing drought stress to the seedlings. Then, the activity of G6PDH in alfalfa seedlings was determined under a range of stress-inducing PEG concentrations. The G6PDH inhibitor Na₃PO₄ was applied to alfalfa seedlings under drought stress, and changes in the indexes described above were determined. The results showed that PEG treatment significantly inhibited the growth of alfalfa seedlings. Plant height, root length, fresh weight, and dry weight decreased with increasing PEG concentrations. Compared with non-stressed seedlings, those subjected to PEG-induced drought stress (15% PEG) showed 28.4% and 19.9% higher contents of H₂O₂ and MDA, respectively, and 49.4% lower G6PDH activity. Application of Na₃PO₄ decreased the activity of G6PDH and caused the symptoms of drought stress to become more severe, suggesting that G6PDH is involved in the regulation of oxidative stress induced by PEG.

XIONG Li-li, YAN Shuang, LI Ping, YANG Guo-zhu, YIN Wei, YAN Xiao-xia, ZHANG Han. Role of glucose-6-phosphate dehydrogenase in the drought tolerance of alfalfa[J]. Acta Prataculturae Sinica, 2018, 27(2): 48-56.

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