Identification of the Cytosolic Glucose-6-Phosphate Dehydrogenase Gene from Strawberry Involved in Cold Stress Response

• Main Authors: Yunting Zhang, Mengwen Luo, Lijuan Cheng, Yuanxiu Lin, Qing Chen, Bo Sun, Xianjie Gu, Yan Wang, Mengyao Li, Ya Luo, Xiaorong Wang, Yong Zhang, Haoru Tang
• Format: Article
• Language: English
• Published: MDPI AG 2020-10-01
• Series: International Journal of Molecular Sciences
• Subjects: Glucose-6-phosphate dehydrogenase; Cold stress; Strawberry; Antioxidant enzymes; Oxidative damage
• Online Access: https://www.mdpi.com/1422-0067/21/19/7322

Glucose-6-phosphate dehydrogenase (G6PDH) plays an important role in plant stress responses. Here, five <i>FaG6PDH</i> sequences were obtained in strawberry, designated as <i>FaG6PDH-CY</i>,<i> FaG6PDH-P1</i>,<i> FaG6PDH-P1.1</i>, <i>FaG6PDH-P2 </i>and <i>FaG6PDH-P0</i>, which were divided into cytosolic (CY) and plastidic (P) isoforms based on the bioinformatic analysis. The respective <i>FaG6PDH</i> genes had distinct expression patterns in all tissues and at different stages of fruit development. Notably, <i>FaG6PDH-CY</i> was the most highly expressed gene among five <i>FaG6PDH</i> members, indicating it encoded the major G6PDH isoform throughout the plant. FaG6PDH positively regulated cold tolerance in strawberry. Inhibition of its activity gave rise to greater cold-induced injury in plant. The <i>FaG6PDH-CY</i> transcript had a significant increase under cold stress, similar to the G6PDH enzyme activity, suggesting a principal participant in response to cold stress. Further study showed that the low-temperature responsiveness (LTR) element in <i>FaG6PDH-CY </i>promoter can promote the gene expression when plant encountered cold stimuli. Besides, <i>FaG6PDH-CY</i> was involved in regulating cold-induced activation of antioxidant enzyme genes (<i>FaSOD</i>, <i>FaCAT</i>, <i>FaAPX</i> and <i>FaGR</i>) and RBOH-dependent ROS generation. The elevated <i>FaG6PDH-CY</i> enhanced ROS-scavenging capability of antioxidant enzymes to suppress ROS excessive accumulation and relieved the oxidative damage, eventually improving the strawberry resistance to cold stress.