Induction of disease resistance in mango fruit by postharvest heat.
Benitez M. M., Acedo A. L. Jr., Jitareerat P., Kanlavanarat S.
Author Affiliation: Postharvest Technology Laboratory, Department of Horticulture, Leyte State University, Visca, Leyte, 6521, Philippines.
: 785-792
Abstract : Mango cv. 'Namdokmai' fruits at the mature-green stage were dipped in 55°C water (HWD) or ambient water (control) for 5 min with or without prior inoculation with the anthracnose pathogen, Colletotrichum gloeosporioides [Glomerella cingulata], and stored at 25°C with 90-95% relative humidity. Anthracnose symptoms developed in both inoculated and un-inoculated fruits, with pathogen inoculation advancing disease development. HWD remarkably delayed the onset of disease infection, reduced the number of infected fruits, and lowered the severity of infection. At the end of storage, HWD-treated fruits had still lower disease severity than unheated fruits. Phenylalanine ammonia lyase (PAL) and ?-1,3-glucanase increased in both peel and pulp of HWD-treated fruit. Pathogen inoculation enhanced PAL and glucanase activity, particularly at the initial stage of storage. The results indicate that HWD reduced disease incidence, partly by inducing defence mechanism in the fruit tissue.