Main content area

A study on exogenous spermidine improving resistance to powdery mildew in melon seedlings

Zhang, X., Li, X. L., Liu, C. M., Liu, L. H., Yang, R. P., Zheng, J. X., Mo, Y. L., Mo, M. M., Yang, J. J.
Acta horticulturae 2017 no.1151 pp. 195-202
Cucumis melo, catalase, catechol oxidase, cultivars, dose response, enzyme activity, foliar spraying, hydrogen peroxide, malondialdehyde, melons, oxidative stress, peroxidase, photosynthesis, pigments, powdery mildew, seedlings, spermidine, superoxide dismutase
Spermidine (Spd) plays important roles in plants resistance to various environment stresses. To determine whether Spd could improve resistance to powdery mildew, we examined the effect of Spd on the disease index, activities of defence enzymes, photosynthetic pigments in susceptible Cucumis melo cultivar '066', '0544' and resistant cultivar 'Yuntian-930' seedlings after powdery mildew inoculation. The results showed that: (1) Exogenous Spd induced Cucumis melon tolerance to powdery mildew based on lower disease index and this induction was dose-dependent (1 mmol L-1); (2) Spd mitigated powdery mildew-induced reduction of photosynthetic pigments; (3) Foliar-spraying Spd increased activities of four defence enzymes (superoxide dismutase, SOD; peroxydase, POD; catalase, CAT; and polyphenol oxidase, PPO) and alleviated increase of malondialdehyde (MDA) and H2O2. In summary, these results suggested that Spd improves photosynthetic capacity via alleviating reduction, alleviates oxidative stress via increasing defence enzyme activities, and finally increases Cucumis melon resistance to powdery mildew.