Biological Control of Green Mould Decay in Postharvest Chinese Bayberriesby Pichia membranaefaciens

摘要

The effect of the yeast antagonist Pichia membranaefaciensfor control of green mould decay caused by Penicilliumcitrinum or Verticicladiella abietina and naturaldecay in postharvest Chinese bayberries (Myrica rubraSeib & Zucc.), and the possible mechanisms were investigated.The results showed that 1/109 colony-formingunits (CFU)/ml of washed cell suspensions of theyeast provided better control of green mould decaythan yeast in culture broth at the same concentration.Treatment with cell-free culture filtrates or autoclavedcell cultures had little effect on disease incidence. Theconcentration of a washed cell suspension of P. membranaefacienshad a significant effect on efficacy in controllingdisease incidence. At a concentration rangefrom 1 · 106 to 1 · 109 CFU/ml, the higher the concentrationof the antagonist, the lower was the incidenceof the disease. In the inoculated wounds of Chinesebayberries, populations of P. membranaefaciensincreased by approximately 145- and 41-fold, respectively,after incubation at 20 deg C for 2 day or at 1 deg C for8 day. P. membranaefaciens significantly induced activitiesof two defence-related enzymes chitinase and b-1,3-glucanase in Chinese bayberries. The in vitro experimentshowed that spore germination and germ tubeelongation of the two pathogens were markedly inhibitedby washed cell suspensions of P. membranaefaciens.In addition, P. membranaefaciens significantlyreduced natural decay in Chinese bayberries. Theseresults indicate that P. membranaefaciens can effectivelyreduce fruit decay possibly by directly inhibiting pathogengrowth and indirectly by inducing disease resistance.Thus, we suggest that P. membranaefaciens haspotential as a biocontrol agent to control fruit decay inChinese bayberries during postharvest storage.