Institution: | 1.College of Agronomy, Guangxi University, Nanning, Guangxi, China ;2.College of Pharmacy, Guangxi University of Chinese Medicine, Nanning, Guangxi, China ;3.College of Life Science and Technology, Guangxi University, Nanning, Guangxi, China ;4.Guangxi Key Laboratory for Agro-Environment and Agro-Product Safety, Nanning, Guangxi, China ; |
Abstract: | Aims Metacaspases are cysteine-dependent proteases, which play essential roles in programmed cell death (PCD), and caspase-3-like protease is the crucial executioner. However, its response mechanism to aluminum (Al)-induced PCD is still elusive. MethodsHere, the type I metacaspase gene in peanut (Arachis hypoganea L.), AhMC1, was cloned from the Al-sensitive cultivar ZH2. Physiological and biochemical methods, as well as gene expression analyses, were employed to explore its function in Al-induced PCD in peanut root tips. ResultsAhMC1 had a 1068-bp open reading frame, encoding a peptide of 355 amino acids, and the purified protein exhibited a high caspase-3-like protease activity. Its expression levels in different tissues of peanut varieties ZH2 and 99–1507 (Al-tolerant) varied under Al-stress conditions. The subcellular localization indicated that AhMC1 was transferred from mitochondria into the cytoplasm. Furthermore, overexpressing AhMC1 reduced the resistance to Al stress. Sense transgenic plants showed a low relative root growth rate, and reduced superoxide dismutase, peroxidase, and catalase activities, compared with wild-type and antisense transgenic plants under Al-stress conditions, but had a high root-cell death rate, and increased Al and maleic dialdehyde contents. ConclusionsThe data suggest that metacaspase AhMC1 is a positive factor in Al-induced PCD in peanut root tips. |