Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (5): 160-167.doi: 10.13560/j.cnki.biotech.bull.1985.2022-0889

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Physiological and Biochemical Analysis of Drought Resistance in Sorghum Cuticular Wax-deficient Mutant sb1

WANG Chun-yu(), LI Zheng-jun, WANG Ping, ZHANG Li-xia()   

  1. Sorghum Research Institute, Liaoning Academy of Agricultural Sciences, Shenyang 110161
  • Received:2022-07-18 Online:2023-05-26 Published:2023-06-08
  • Contact: ZHANG Li-xia E-mail:wangchunyu88899@126.com;39533597@qq.com

Abstract:

The drought tolerance trait of plant is related to the wax accumulation on the surface. Sorghum is a cereal crop that can survive under extreme drought stress, its surfaces of stems and leaves were covered with a thick layer of wax on the. The study on the difference of drought resistance in sorghum with or without cuticular wax may provide a theoretical basis for breeding drought-resistant sorghum varieties and revealing the molecular mechanism of drought resistance. Sorghum cv. BTx623(with cuticular wax)and cuticular wax-deficient mutant sb1(without cuticular wax)were used as experimental materials. Firstly, agronomic traits of BTx623 and sb1 were recoded and leaf surface wax structure was observed by using electron microscope. Secondly, the influences of the presence and absence of cuticular wax on the water loss rates of excised leaves and chlorophyll leaching rates were analyzed. Finally, phenotype changes, activities of SOD(superoxide dismutase)and POD(peroxidase)were detected under drought stress. Compared to sorghum cv. BTx623, the height of cuticular wax-deficient mutant sb1 significantly decreased, while the heading-flowering period delayed for one week. Sheticular wax was absent on the distal axial surface of leaves, and no significant variance in other agronomic traits was found. Water loss rates of excised leaves and chlorophyll leaching rates of mutant sb1 were significantly higher than those of BTx623. Under the drought stress treatment, the activities of SOD and POD were induced in both BTx623 and sb1, while the enzyme activities of BTx623 were significantly higher than those of sb1. After drought treatment, most leaves of sb1 were withered and dried after 96 h with re-watering. This study demonstrate that leaf's permeability is enhanced and leaf's ability to scavenge reactive oxygen species is weakened in cuticular wax-deficient mutant sb1 compared to BTx623, which indicates the presence of cuticular wax plays an important role in drought tolerance.

Key words: sorghum, cuticular wax, drought stress, permeability, antioxidant enzyme