Antioxidant enzyme activities during somatic embryogenesis in Musa acuminata Colla (AAA group) ‘Grand Naine’ and Musa spp. (AAB group) ‘Rasthali’

Abstract

Antioxidant enzymes play a major role in scavenging reactive oxygen species that arise during somatic embryogenesis (SE). Activity levels of antioxidant enzymes such as peroxidase (POX), catalase (CAT), and superoxide dismutase (SOD) were investigated during developmental stages of SE of Musa acuminata Colla (AAA group) ‘Grand Naine’ and Musa spp. (AAB group) ‘Rasthali’. Using native polyacrylamide gel electrophoresis, five POX isoforms were detected in ‘Rasthali’, and four POX isoforms were observed in ‘Grand Naine’. The POX1 isoform was highly expressed in non-embryogenic callus (NEC) of both cultivars, and the POX2 isoform was present in somatic embryos (se) at 0, 30, 45, and 60 d of development of ‘Rasthali’, but not ‘Grand Naine’. Among two CAT isoforms, the CAT2 isoform showed higher expression in embryonic stages than in vegetative stages in explants and NEC of both cultivars. A total of five SOD isoforms detected in different developmental stages of both cultivars, SOD4 and SOD5, were detected only during the developmental stages of se. The enzyme assay showed that the highest CAT and SOD activity was in embryogenic callus (EC) of both cultivars, whereas activity of POX was reduced in EC. During somatic embryo development, the activity of SOD, POX, and CAT was found to be higher in the early globular stage than in the later coleoptilar stage embryos. During germination, the activity of SOD and POX was found to be higher in germinating se of ‘Grand Naine’. The specifically detected isoforms can be used as biochemical markers.