2020, VOLUME 7 ISSUE 1Pages: 255-267
Differential responses of antioxidants and dehydrin in two Switchgrass (Panicum virgatum L.) cultivars contrasting in drought tolerance
Y. M. Liu#, G. F. Hu#, G. Q. Wu, L. L. Yan, B. Y. Zhao* and X. Z. Zhang*
*Department of Crop and Soil Environmental Science and Department of Horticulture, Virginia Tech, Blacksburg, VA, USA
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Drought stress is a major limiting factor for plant growth and production, including biofuel crops. This study was designed to investigate antioxidant metabolism and dehydrin responses to drought stress in two cultivars (drought tolerant Alamo and drought sensitive Dacotah) contrasting in drought tolerance of Switchgrass (Panicum virgatum). Alamo and Dacotah were subjected to control (25.7%–28.3% soil water content) or drought treatment (27.2%–4.7% soil water content) conditions for 24 d in growth chambers. Our results showed that drought treatment decreased leaf relative water content (RWC), increased leaf electrolyte leakage (EL) and leaf malondialdehyde (MDA) content in two Switchgrass cultivars. However, Alamo had higher leaf RWC, lower leaf EL and MDA compared to Dacotah at 24 d of drought treatment. Drought treatment also increased superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activities in Alamo and Dacotah, Alamo had higher SOD, CAT and APX activities and greater abundance of SOD and APX isozymes than Dacotah at 24 d of drought treatment. Alamo also had higher abundance of 55 KDa and 18 KDa dehydrin accumulation than Dacotah under 24 d of drought treatment. Relative genes expression level of PvCAT1, PvAPX2 and PvERD in Alamo were significantly higher than Dacotah at 24 d of drought treatment. Our results suggest that antioxidants and dehydrin played an important role in Switchgrass drought tolerance. Antioxidants and dehydrin abundance could be screening indicators to identify drought tolerance in Switchgrass populations.