Isolation,Identification,Biological Characteristics And Biological Control Of Pathogens Which Latently Infecting In Chinese Olive Fruit

Canarium album(Lour.)Raeusch is a popular subtropical fruit in southern of China.The Chinese olive fruit have abundant nutritional with powerful health care function and medicinal value.In recent years,with its growing cultivated area and extensive management,post-harvest disease genus and injured degreealso increase day by day,leading to lower commodity rate,quality of fruit and storage period.The latent infection of pathogens is a major factor for post-harvest disease,and so it's one of the problems during storage of 'Changying' Chinese olive fruit that needs urgent resolution.At present there are only a few researches of the species or the biological characteristics of the latent infection of pathogens of'Changying' Chinese olive fruit.The latent infection of pathogens from 'Changying' Chinese olive were isolated in this study by tissue isolation method in some specific growth periods of 'Changying'Chinese olive,including full-blossom period,young fruit stage,fruit enlargement period,prematuration period and maturation period.Then the combination of morphology and molecular biology with phylogenetic analysis were used to identify the species of pathogens causing'Changying' Chinese olive fruit rot.In order to provide a theoretical basis for prevention,the biological characteristics of two higher isolation frequency major pathogens,and the biological control of one of two major pathogens were researched.The main results are as follows:1.Isolation and identification of latent pathogens of 'Changying' Chinese olive fruit:Six kind of pathogenic fungi were isolated and identified using tissue isolation method from flower and fruit of'Changying' Chinese olive,including Botryosphaeriaceae,Pestalotiopsis,Phomopsis,Phanerochaete,Guignardia and Fumago Pers.ex Sacc.Among them,Botryosphaeria dothidea and Pestalotiopsis microspora were the main latent infection pathogenic fungis causing 'Changying'Chinese olive postharvest decay.They are infected 'Changying' Chinese olive fruit in the same period which is full-blossom period.The main pathogenic fungi of leaves are consistent with isolation of fruit were discovered through isolation and identification of the pathogenic fungi in specific growth period of 'Changying'Chinese olive.This result indicated that there are cross-infection phenomenon of main pathogenic fungi which are isolated from 'Changying' Chinese olive fruit and leaves.2.The biological characteristics of Botryosphaeria dothidea:For the mycelial growth of Botryosphaeria dothidea,the optimum pH was 6.the optimum temperature was 28?,the optimal light condition were all-day illumination and the alternation of light and darkness.The optimal pH,temperature and favorable light condition for the production of stroma of the B.dothidea were 7,26?28?,and the all-day illumination,respectively.The optimal pH and temperature for ascospore germination of the B.dothidea were 7 and 28?.The optimum carbon sources were glucose and sucrose,and the optimum nitrogen sources was peptone for B.dothidea growth,then producted more stroma in sucrose and maltose as the carbon source and peptone as the nitrogen source.The ascospore germination needed high relative humidity,the germination rate was higest under 100%relative humidity[(79.9±1.52)%],and the ascospore could not germinate when the relative humidity was lower than 80%.The mycelial and ascospore lethal temperature were 56?(30 min)and 60?(30 min).3.The biological characteristics of Pestalotiopsis microspora:The optimal pH,temperature and favorable light condition for the mycelial growth of Pestalotiopsis microspora were 6,24?26?,and all-day illumination,respectively.For the production of conidium of the P.microspora,the optimum pH was 7,the optimum temperature was 24?26?,the optimal light condition was alternation of light and darkness.The optimal pH,temperature and favorable light condition for conidium germination of P.microspora were 6,26-28? and complete darkness.The fungi grew best in D-fructose and mannitol as the carbon source and peptone as the nitrogen source,then producted more conidium in sucrose and glucose as the carbon source and peptone as the nitrogen source.The conidium germination needed high relative humidity,the germination rate was higest under 100%relative humidity[(52.81±2.66)%],and the conidium could not germinate when the relative humidity was lower than 85%.The mycelial and conidium lethal temperature were 54?(30 min)and 56?(20 min).4.The biological control of Pestalotiopsis microspora:We found that the supernatant of LY-1 had the best effect of antagonism among LY-1,TNX-1 and MG-3 by using in vitro screening method and living donor screening method.Then we researched concentration,temperature and pH impact on the effect of the antagonism of supernatant.The results showed that the concentration of supernatant had a great influence on the antagonism,and with the concentration increased(sparse multiple reduced),the antagonism also increased.The temperature had no significant effect on the.antagonism of supernatant of LY-1 strain.The inhibition rate decreased by 10%with the treated temperature increased from 40? to 120?.So the antagonistic substance of supernatant was a kind of thermal stability material.Adjusting the treat pH higher than 6,the effect of antagonism was better and has a good sustained antagonism.However,the effect of antagonism was worse when adjusting the treat pH below 6.Therefore,the alkaline condition conducive to maintaining antagonism of the antagonistic substance.