Diversity And Salt Resistance Characteristics Of Yeast From Typical Tidal And The Qinghai Gobi Desert In China

From July 2020 to May 2021,members of the research team collected a total of 92transmembrane seawater samples from typical coastal tidal flats in China-Hangzhou Bay,Beibu Gulf and Bohai Bay,as well as samples from Qaidam Basin-Qinghai Haixi Mongolia 39 samples from the Gobi Desert in the Tibetan Autonomous Prefecture,including 26 soil sediments and 13 plant samples.Varieties of yeasts were isolated,purified,identified and preserved from the above samples to understand the distribution and species diversity of yeasts in typical coastal mudflats in China and the Gobi Desert in Qinghai;at the same time,the salt tolerance characteristics of representative species were studied.The main results are as follows in the study:1.A total of 731 yeast strains were isolated from 92 seawater samples collected from typical coastal tidal flats in China,such as Beibu Gulf,Bohai Bay and Hangzhou Bay,including 92 species from 48 genera.Among them,Diutina catenulata was the dominant species,accounting for 19.43%of all isolated yeast strains.By comparing the strains of yeasts isolated from Beibu Gulf,Bohai Bay and Hangzhou Bay,it was found that Rhodotorula mucilaginosa,Galactomyces candidum,Cystobasidium minutum,Candida pseudolambica and Candida parapsilosis were isolated in these three different regions.The relative abundance analysis of isolate-able yeasts at 44 sampling sites in three regions showed that the BH10 site in Bohai Bay had the highest relative abundance of yeasts.The analysis of alpha diversity showed that the Bohai Bay area was larger than the Beibu Gulf and Hangzhou Bay areas in terms of abundance index.In terms of diversity index,the Bohai Bay area in the Xiangnon index is larger than the Hangzhou Bay area;the Simpson index in the Beibu Gulf area is smaller than that in the Bohai Bay and Hangzhou Bay areas.In terms of evenness index,Beibu Gulf is smaller than Bohai Bay and Hangzhou Bay.Using rare species to estimate the species diversity index is consistent with the richness,and the Bohai Bay area is larger than the Beibu Gulf and Hangzhou Bay areas.The PCOA analysis of?-diversity shows that yeast communities in the same area are clustered together,yeasts in different areas overlap each other,and all species in the Bohai Bay area are included in the Beibu Gulf and Hangzhou Bay areas,indicating that the Bohai Bay has a high diversity in species composition.It is very similar to Beibu Gulf and Hangzhou Bay.2.A total of 219 strains of yeasts were isolated from 39 samples(26 soil sediments and 13 plants)from the Gobi Desert,Haixi Mongolian and Tibetan Autonomous Prefecture,Qinghai,China,9 soil samples with salinity not exceeding 34.32‰and 6 yeasts were isolated from 1 plant samples,but no yeasts were found in crust samples.A total of 24species from 14 genera were isolated,including 5 new species.Naganishia albida,Filobasidium sp.,Diutina catenulata,Filobasidium magnum were the dominant species,accounting for 31.05%,12.79%,11.42%,and 9.59%of the total number of isolated strains.Vishniacozyma sp.,Kondoa sp.,Symmetrospora sp.,Filobasidium sp.,Teunia sp.are five new species.By comparing the species of yeast strains from different isolated sources of soil and plants,it was found that Naganishia albida,Filobasidium magnum,Papiliotrema laurentii,Teunia korlaensis,Udeniomyces puniceus,Symmetrospora coprosmaezhe species were isolated in these two types of isolates.By comparing the diversity of yeast species from different isolated sources,it was found that the yeasts isolated from soil wasere significantly less than the yeasthoset isolated from plants in terms of the number of strains and species.It The results shows that there are more yeast resources in plants.3.Taking Kodamaea ohmeri,Pichia kudriavzevii,Metschnikowia bicuspidata,Metschnikowia bicuspidata yeast species in China's typical coastal tidal flat samples and Diutina,Naganishia,Vishniacozyma yeast species in Qinghai Gobi Desert samples as research objects.And 55 yeast strains from plant samples were tested for salt tolerance.By comparing the yeasts from the Gobi Desert in Qinghai,we found that the growth delay period(2 h)of the strains derived from the high salinity soil samples of the same species was significantly shorter than that of the lichen-derived strains and the strains in the plant samples(18-21 h),and the growth rate(4.2?5.5×10~3 OD/min)of the strains in the high salinity soil samples was significantly higher than that in the lichen and low salinity soil samples(2×10~3 OD/min).It shows that the strains from high-salt environment can adapt well to higher salt stress.In addition,the comparison between the yeast strains isolated from the Gobi Desert of Qinghai and the seawater of Bohai Bay showed that the salt tolerance of the salt-tolerant strains from different environmental sources was also different.By comparing yeasts isolated from coastal beaches,we found that the same strain has significant or extremely significant differences in lag period,growth rate and utilization efficiency;different strains of the same species have significant differences in lag period,growth rate and utilization efficiency,which.showed varying degrees of difference or no significant difference.The salt tolerance of Kodamaea ohmeri species is the best able to tolerate salt concentrations above 15%.Pichia kudriavzevii species is tolerant of salinity below 6%.Metschnikowia bicuspidata species are tolerant of environments with salinity concentrations below 9%.Metschnikowia bicuspidata species are tolerant to salt concentrations below 6%.