Structures Communities And Biodiversity Of Yeast In Flowers Of Wine Grape

Yeast is an important flora in the process of wine brewing.They synthesize aromatic substances in wine and have vital impact on the quality of wine.Yeasts are also very common in the natural environment and widely exist in the environment related to grapes.In this paper,culture and non-culture techniques were used to isolate,collect and identify yeasts from different regions,and obtain yeast resources.The taxonomic status of novel species of yeast were established,and the structure of fungal community in the topsoil of vineyard was analyzed.In this study,65 grape flower samples of 7 wine grape species were collected from vineyard of Nanliang town(Yinchuan,Ningxia),Yuquanying(Yinchuan,Ningxia)and Shihezi(Xinjiang).The yeasts were isolated from grape flower by dilution and spreading,and cultured with YM(Yeast Extract Malt Extract Agar)and PDA(Potato Dextrose Agar)plate culture medium.After purification and culture,the D1/D2 region of large subunit ribosomal DNA(26S rDNA)was sequenced.A total of 554 strains of yeast were isolated,of which 11 were suspected novel species.210 strains of yeast were isolated from grape flower samples from vineyard in Nanliang(Yinchuan,Ningxia),belonging to 15 genera and24 species,of which Filobasidium,Aureobasidium and Cryptococcus were dominant genera.84 strains of yeast were isolated from grape flower samples of vineyard in Yuquanying(Yinchuan,Ningxia),belonging to 8 genera and 9 species.The dominant genera were Filobasidium,Aureobasidium and Candida.260 strains of yeast were isolated from grape flower samples of vineyard in Shihezi,belonging to 12 genera and 16 species,of which Filobasidium and Aureobasidium were dominant genera.Filobasidium and Aureobasidium were the common dominant genera of grape flowers in three vineyards.In addition,at the species level,the common yeast strains in the grape flower samples of the three vineyards included Aureobasidium pullulans,Vishniacozyma carnescens,Filobasidium magnum and Cryptococcus tephrensis.The results of strain isolation showed that the diversity of yeasts in flowers was much higher than that in soil,indicating that the correlation between yeasts in flowers and soil was weak,and it may be affected by external effects such as wind and insects.Five suspected novel species of yeast were identified by polygenic system analysis and phenotypic analysis.Three novel species of yeast that Wickerhamomyces kurtzmani sp.nov.,Naganishia floricola sp.nov.,Halobasidium floricola sp.nov.were established.In addition,through the enzyme activity experiment,216 yeast strains with casein activity were screened,which can be used in the follow-up application development.The topsoil of Cabernet Sauvignon vineyard in Nanliang Town of Yinchuan in Ningxia,Yuquanying of Yinchuan in Ningxia and Shihezi in Xinjiang were collected,and the total DNA,of soil samples was extracted.The community structure and characteristics of fungi in the topsoil of vineyard were described by high-throughput sequencing analysis of ITS2.The results of sequencing showed that at the level of phylum,class,order and family,the most abundant components in the three groups were Ascomycota,Sordariomycetes,Hypocreales and Nectriaceae,respectively.There is no common dominant fungal genus at the genus level.Pseudogymnoascus is the dominant fungal genus in Nanliang Town and Yuquanying(Yinchuan,Ningxia),and an unclassified fungal genus is the dominant genus in the samples of Shihezi(Xinjiang).The fungal genera detected in this study include two yeast genera,Phaeococcomyces and Solicoccozyma.The diversity of fungi in the topsoil of Nanliang Town and Yuquanying is similar,and they are significantly different from those in Shihezi,indicating that the structure of fungal community in soil is related to geographical factors.The fungal diversity of surface soil samples of Shihezi vineyard was higher than that of Nanliang Town and Yuquanying.