Biochemical markers as a useful tool for the early identification of Fusarium oxysporum f.sp. cubense,race 1 resistance banana clones

Abstract

Panama disease of banana (Musa spp) caused by the fungus Fusarium oxysporum f. sp. Cubense (FOC), is a serious constraint both to the commercial production of banana and cultivation for subsistence agriculture. Chemical control is not economically effective and is also hazardous to the environment and human health. Breeding for disease resistance is an alternative strategy, which leads to the development of resistance clones. Field evaluation is the most reliable method of screening for disease resistance, but it is demanding in terms of cost, manpower and space requirements. Another approach of screening hybrids at the sucker's stage (planting material) through biochemical markers has been found to be effective in early identification of resistant hybrids. The resistance mechanisms involving the role of phenol, PAL, oxidative enzymes like peroxidase (PO), polyphenol oxidase (PPO), superoxide dismutase (SOD), catalase and PR-proteins like chitinase, β-1-3 glucanase were studied and they showed relatively higher activity in resistant hybrids than susceptible hybrids. Isozyme analysis of peroxidase (PO) and polyphenol oxidase (PPO) was also carried out in cultivars and hybrids, which revealed the induction of specific isoforms in the resistant hybrids upon challenge inoculation. This could be a useful tool for early identification of F. oxysporum f. sp. cubense resistance banana clones.