Research On The Control Mechanism Of Trichokonins Against Gray Mold On Phalaenopsis

Trichoderma is an important biocontrol fungi, Peptaibols is a special kind ofα-aminoisobutyric acid riched antimicrobial peptides with broad spectrum of leathaleffect on some fungi, protozoa, resistant bacteria. In recent years, gray mold is a seriousdisease on the Phalaenopsis spp. This paper researched on trichokonins (TKs), a newantimicrobial peptides isolated from Trichoderma pseudokoningii SMF2strains. Botrytiscinerea which were isolated from Phalaenopsis spp.was used for the test pathogens. Thecontrol mechanism of trichokonins against gray mold on Phalaenopsis spp.were reported.All the results include the follows:1． The pathogens of gray mold on Phalaenopsis spp. were isolated and identified asBotrytis cinerea, which belonging Deuteromycotina, Moniliales.The pathogens were identified by morphology and molecular biology method.Results showed that the teleomorph and anamorph state of gray mold on Phalaenopsisspp. has homology of99.8%compared with Botryotinia fuckeliana and Botrytis Cinerea,which were reported in GenBank. Combined with morphological characteristics, it couldbe concluded that the teleomorph pathogens of gray mold on Phalaenopsis spp. isBotryotinia fuckeliana, Helotiales, Ascomycotina. The anamorph of pathogens is Botrytiscinerea, Moniliales, Deuteromycotina.2． The control mechanism of trichokonins on gray mold mainly includes threeaspects: inhibitting effection, induced resistance and promote plant growth.The effect of trichokonins on Botrytis cinerea were determined, include hyphaegrowth, spore germination, sclerotium and the sclerotia germination, hyphae conductivityand dissolved matter, soluble protein contents of the mycelium. Results showed thattrichokonins can inhibit the mycelial growth, spores and the sclerotia germination,increase the permeability of cell membranes, reduce the soluble protein contents ofB. cinerea.The activity of defense-related enzyme include POD, PPO, PAL; resistance-relatedenzyme SOD, CAT, MDA; pathogenesis-related enzyme β-1,3glucanase, chitinase inPhalaenopsis spp. were assayed. Results showed that after induced by trichokonins, the POD, PPO, PAL, SOD, CAT and other defense-related enzymes and resistance enzymeactivity were improved, the content of harmful substances MDA was reduced. Aftertreatment with trichokonins, the pathogenesis-related enzyme activity also increased.It was also found that after treatment with trichokonins growth of Phalaenopsis spp.is obviously stronger than the control.The biomass aboveground and belowground haveincreased, the grow of roots also strengthened.3． Trichokonins has good control effect on gray mold, and the technology system oftrichokonins induced resistance to gray mold on Phalaenopsis spp. was established．The fungicidal and inhibitory effect of trichokonins against B. cinerea weredetermined in vitro. Results showed that the fungicidal effect of trichokonins is weakerthan pyrimethanil, while it can persist for a longer time. The effect of inhibition B.cinerea is obvioused. Trichokonins can be used by spraying and irrigating. Bactericidaleffect is good when spraying, inhibitory effect is good when irrigating.The technology system of trichokonins induced resistance to gray mold onPhalaenopsis spp. were established. The best concentration of trichokonins is0.2mg/L;Irrigating induced relative control effect is better; When the interval between inducedinoculation and challenge inoculation are1day and3day, trichokonins’s inducedresistance is better; The sooner treated with trichokonins during growth and developmentof plants, the better of the induced effect.