Study On The Mechanism Of Biocontrol Yeast Against Grape Gray Mould Blight And Grape Anthracnose

Grape anthracnose which caused by Colletotrichum gloeosporioides is a common disease of grape.It could infect grape berries and cause reduction of grape production and quality.Grape gray mould blight is a common disease which cause the most serious loss in grape postharvest storage.It also occurs in vineyard.At present,chemical agent is the primary method to control grape anthracnose and grape gray mould blight.But there are some disadvantages,such as environment pollution,pesticide residue and harmful to human body.Biological control is a environmental and effective method to control disease,thus received wide attention.In the midst of biological control,biocontrol yeasts are widely studied because of its great efficiency and nontoxicity.In this study,the yeasts which could inhibit C.gloeosporioides and B.cinerea were identified from the lab killer yeasts collection.The biological efficiency and mechanism of biocontrol yeasts were preliminary studied.The tartaric acid and tea polyphenols were used to improve biocontrol efficiency of yeasts.The results are as follows:1.Three yeasts(LFA802,L24 and GA8)which could inhibit C.gloeosporioides were selected from 216 killer yeasts.The inhibition effects of LFA802,L24 and GA8 were 21.30%,21.89%and 79.28%respectively.The cell-free filtrate of three yeasts showed inhibition on C.gloeosporioides.The inhibition rate of GA8 volatile compounds was 72.78%.All of three yeasts exhibited inhibition on C.gloeosporioides spores germination,and the higher the concentration of yeast cells the better effect of the inhibition.The LFA802,L24 and GA8(10~8cfu/m L)efficiency of control grape anthracnose were 72.62%,65.08%and 75.98%in vivo.All of three yeasts could produceβ-1,3-glucanase and chitinase.All of three yeasts could colonize on the surface and wounds of grape berry.The cell-free filtrate showed the best inhibition efficiency on C.gloeosporioides when the culture conditions were NYDA culture medium,temperature 25℃,medium capacity 20 m L,p H 4,culture mode 24 h concussion,culture time 144h.2.A yeast(GA8)which could inhibit B.cinerea was selected from 216 killer yeasts.The substrates produced by GA8 showed inhibition on B.cinerea.The inhibition rate of cell-free filtrate,high temperature treated cell-free filtrate and volatile compounds were 22.31%,9.91%and 71.90%respectively.The GA8(10~8cfu/m L)preventive and curing efficiency of grape gray mould blight were 72.53%and 19.78%respectively in vivo.The strain GA8(10~7cfu/m L)could inhibit B.cinerea spore germination with rate 93.30%.At 4℃centigrade,the strain GA8 could colonize surface and wounds of grape rapidly and keep stable.3.It found that decanoic acid and 9-decenoic acid showed remarkable inhibition on B.cinerea in preliminary activity identification.Different concentration of decanoic acid showed different inhibition efficiency on B.cinerea.B.cinerea couldn’t grow when the concentration is 0.55μL/m L.When the 9-decenoic acid concentration is from 0.11 to 0.55μL/m L,B.cinerea could be completely inhibited.Decanoic acid and 9-decenoic acid showed inhibition on B.cinerea spore germination.The effect didn’t change with the concentration.The inhibition efficiency was 60%to 70%.The volatile compounds produced by GA8 could control grape gray mould blight.The incidence of gray mould reduced 22.08%relative to control group.4.Tea polyphenols(TP)in combination with strain GA8 showed a lower infection rate of grape spots than strain GA8 alone.TP had inhibition on spore germination of C.gloeosporioides,the higher concentration the better effect.In vitro,TP had effect on GA8 and low concentration(0.01%,0.05%and 0.1%)improved the growth of GA8,high concentration(0.5%and 1%)inhibited the growth of GA8.TP had no effect on growth of GA8in vivo.TP at the concentration of 0.01%,0.05%,0.1%,0.5%and 1%had no effect on the mycelium growth of C.gloeosporioides.Tartaric acid(TA)with a concentration of 1.2%,1.6%and 2%in combination with strain GA8(10~6cfu/m L)had a lower occurence rate of spots than strain GA8(10~8cfu/m L)alone.TA had inhibition on spore germination of C.gloeosporioides,the higher concentration the better effect.TA at the concentration of 0.4%,0.8%,1.2%,1.6%and 2%showed compete inhibition on the mycelium growth of C.gloeosporioides.In vitro,TA had effect on GA8 and low concentration(0.4%,0.8%and 1.2%)improved the growth of GA8,high concentration(1.6%and 2%)inhibited the growth of GA8.In vivo,TA with concentration of 0.4%and 0.8%had no effect on colonization of GA8 on grape and TA with concentration of 1.2%,1.6%and 2%reduced colonization ability.