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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Water Management Research » Research » Publications at this Location » Publication #311969
Title: Effects of pre- and post-harvest application of selenium on inducing disease resistance and selenium accumulation in fruits

Author
item WU, ZHI-LIN - Anhui Agricultural University
item YIN, XUE-BIN - University Of Science And Technology Of China
item Banuelos, Gary
item LIN, ZHI-QING - Southern Illinois University
item YUAN, LIN-XI - University Of Science And Technology Of China
item LIU, YING - University Of Science And Technology Of China
item LI, MIAO - Anhui Agricultural University

Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary: Pencicillium expansum and Botrytis cinerea are two major fungal pathogens, which cause severe economic losses of fruits and vegetables. Tomato and apple fruits are two main susceptible hosts of these pathogens. Management of decay caused by B. cinerea and P. expansum has become important for ensuring the quality and safety of various fruits. However, the use of fungicides is becoming increasingly restricted because of concerns for environment and health, as well as the development of fungicide resistance by pathogens. Selenium (Se), as an essential micronutrient for humans, may be effective in improving a plant’s resistance to fungal pathogens and increase a plant’s antioxidant capacity. In this study, effects of pre- and post-harvest applications of Se were respectively investigated on inducing disease resistance in tomatoes and apples. The spraying at pre- and postharvest significantly reduced decay incidence on apple and tomato fruit caused by P. expansum and B. cinerea, respectively, compared with control groups without Se. These results suggest that Se might serve as a potential alternative to synthetic fungicides for the control of the postharvest disease of fruit caused by P. expansum and B. cinerea by stimulating fungal protection through Se-activated antioxidant activities within the fruit.

Technical Abstract: Botrytis cinerea, a ubiquitous fungal pathogen, causes severe damage (gray mold rot) on a large number of economically important fruits, vegetables, and ornamental crops at both pre- and post-harvest, which renders fruits unmarketable. Penicillium expansum is a widely spread fungal pathogen that causes blue mold rot in a variety of fruits, including apples, pears, peaches, and cherries. Many synthetic fungicides have been used intensively since the 1950s, resulting in the selection of resistant mutants in natural populations of phytopathogenic fungi. However, the use of fungicides is becoming increasingly restricted because of concerns for environment and health, as well as the development of fungicide resistance by pathogens. Selenium (Se), as an essential micronutrient for biological systems, may be effective in improving a plant’s resistance to fungal pathogens and increase the plant’s antioxidant capacity. Selenium has been shown to possess an inhibitory effect on some certain pathogens, including Fusarium. In this study, effects of pre- and post-harvest application of Se as sodium selenite were respectively investigated on inducing disease resistance in apples and tomatoes. Results showed that pre-harvest and post-harvest treatment with Se significantly reduced lesion diameters and decay incidence on apple and tomato fruit caused by P. expansum and B. cinerea respectively, compared with control groups (without Se). Pre-harvest treatment of fruits with Se induced polyphenol oxidase (PPO), peroxidase (POD) activities, and enhanced the content of phenolic compounds during the early storage time. Selenium applied at a concentration of 10 mg Se/L showed direct fungi toxicity on two the fungal pathogens and significantly inhibited mycelial growth and spore germination. Relatively, Se showed more obvious inhibitory effect on P. expansum than B. cinerea in both in vivo and in vitro experiments. Furthermore, with the use of an oxidant sensitive probe 2,7- dichlorofluorescin (DCHF-DA), we found that Se could induce the generation of intracellular reactive oxygen species (ROS) in vitro. These results suggest that Se might serve as a potential alternative to synthetic fungicides for the control of the postharvest disease of fruit caused by P. expansum and B. cinerea. However, further study on the mechanism of Se against fungal pathogens at the biochemical and molecular level is still needed.