Sugar Protectants Improve The Thermotolerance And Biocontrol Efficacy Of The Biocontrol Yeast,Candida Oleophila

At present,biological control methods have broad prospects in managing various pre-harvest and post-harvest diseases.However,the activity and viability of biocontrol yeast begin to decline under relatively adverse environment,resulting in reduction in control effect.Various sugars have been used as additives in recent years to protect various biocompatible yeasts from adverse environmental stresses.However,the protective effects of maltose and lactose as sugar protectants are not well understood.In this study,the protective effects of six sugars have been examined.After screening,protective effect of maltose and lactose is significant.for the yeast Candida oleophila cells suspended in 5% or 10%(w/v)in the malt sugar or lactose under 45 o C in 10 minutes.It was found that both solutions provided significant protection effect at different concentrations.The research results show that:1.Compared with cells suspended in sterile distilled water(control)and exposed to 45 o C,the survival rate,enzyme activity and gene expression of catalase(CAT),thioredoxin reductase(Trx R)and glutathione reductase(GR)has significantly increased.Not only that,C.oleophila cells suspended in maltose and lactose solution also showed higher ATP level than cells in the control group.Proved that the oxidative damage of mitochondria was reduced.2.After high temperature stress treatment,C.oleophila yeasts suspended and non-suspended in the 10% sugar or lactose were tested for biocontrol efficacy.The results showed that the disease incidence and lesion diameter of the sugar-treated group were lower than those in the control group.sugar or lactose.In conclusion,maltose and lactose have shown great application potential as effective biocontrol yeast sugar protectants,also providing a reliable basis for further research of biocontrol yeast protectants.