Inhibitory activity of tea polyphenol and Candida ernobii against Diplodia natalensis infections.
OBJECTIVE
To investigate the effect of tea polyphenol (TP) and Candida ernobii alone or in combination against postharvest disease (Diplodia natalensis) in citrus fruit and to evaluate the possible mechanisms involved.


RESULTS
TP at concentrations of 0.1%, 0.5% and 1.0% alone, or in combination with C. ernobii (1x10(6) CFU ml(-1)), showed a lower infection rate of stem-end rot. TP at the concentration of 0.5% or above significantly inhibited the spore germination of D. natalensis. TP at the concentration of 1.0% showed inhibitary ability on mycelium growth of D. natalensis. The addition of TP did not affect the growth of C. ernobii in vitro and significantly increased the population of C. ernobii in vivo.


CONCLUSIONS
TP exhibited an inhibitory effect against D. natalensis and improved the biocontrol efficacy of C. ernobii. It was direct because of the inhibitory effects of TP on spore germination and mycelial growth of D. natalensis in vitro and indirect because of the increased populations of C. ernobii in vivo.


CONCLUSIONS
The results suggested that TP alone or in combination with biocontrol agents has great potential in commercial management of postharvest diseases in fruits.
National Centre of Citrus Breeding, Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agriculture University, Wuhan, Hubei, China.
H M
HM
Liu
National Centre of Citrus Breeding, Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agriculture University, Wuhan, Hubei, China.
J H
JH
Guo
National Centre of Citrus Breeding, Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agriculture University, Wuhan, Hubei, China.
P
P
Liu
National Centre of Citrus Breeding, Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agriculture University, Wuhan, Hubei, China.
Y J
YJ
Cheng
National Centre of Citrus Breeding, Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agriculture University, Wuhan, Hubei, China.
B Q
BQ
Wang
National Centre of Citrus Breeding, Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agriculture University, Wuhan, Hubei, China.
C A
CA
Long
National Centre of Citrus Breeding, Key Laboratory of Horticultural Plant Biology of Ministry of Education, Huazhong Agriculture University, Wuhan, Hubei, China.
B X
BX
Deng
D000898:Antibiosis; D002175:Candida / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D002957:Citrus / Q000382:microbiology*; D005419:Flavonoids / Q000494:pharmacology*; D003904:Mitosporic Fungi / Q000187:drug effects* / Q000254:growth & development; D025282:Mycelium / Q000187:drug effects / Q000254:growth & development; D010636:Phenols / Q000494:pharmacology*; D010935:Plant Diseases / Q000517:prevention & control*; D059808:Polyphenols; D013172:Spores, Fungal / Q000187:drug effects / Q000254:growth & development; D013662:Tea / Q000737:chemistry*
D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D013662:Tea