The Study On Diversity Of Contaminated Fungus Species Of Potato Tissue Culture

In the middle and late last century,potato was the main food in many impoverished areas of our country.As the cultivation area expands year by year,the potato industry has developed rapidly,and its status and role have also changed.Especially since my country implemented the strategy of turning potatoes into staple foods,many regions have put potatoes as the focus of poverty alleviation,and potatoes have become an important food crop that leads farmers to get rid of poverty and become rich.Degradation of potato varieties seriously restricts the development of the potato industry,and the application of virus-free test-tube plantlet tissue culture technology on potatoes has fundamentally solved the problems of virus invasion and accumulation and variety degradation.And pollution is one of the most difficult problems in the process of tissue culture.If it is not prevented and controlled,it will cause time and economic waste and loss.In this study,the fungi that caused pollution during the cultivation of potato tissue cultured seedlings were isolated and identified,the harm of the contaminated bacteria to the tissue cultured seedlings was investigated,and the contaminated bacteria were systematically classified and studied on their diversity.For the three contaminating bacteria that caused serious losses,the indoor virulence test was carried out with 11 fungicides to provide a basis for subsequent screening of antibacterial agents.The main findings are as follows:1 Diversity of contaminated fungi from potato plantlets in vitro The contaminated potato plantlets were collected from the Tissue Culture Laboratory,and pure contaminated fungi were isolated and cultured.The internal transcribed spacer(ITS)and large subunit(Lsu)sequences of contaminated fungi were determined,construction of phylogenetic tree for diversity analysis.The results showed that the 27 contaminated fungi belonged to the flora of Bionectriaceae,Parengyodontium of Cordycipitaceae,Fusarium of Nectriaceae,Alternaria of Pleosporaceae,Mucor of Rhizopodaceae,Mulina of Physalacriaceae,coriodium of Polyporaceae,Aspergillus and Penicillium of Laclus,Cladosporium of Cladosporium,Aspergillus and Cladosporium of Cladosporiaceae.The results showed that the species of fungi in potato tissue culture were complex and had rich diversity.Aspergillus sp.、Cladosporium sphaerospermum、Penicillium sp.、Fusarium spp.、Clonostachys rosea、Fusarium spp.、Alternaria spp.、Aspergillus ochraceus and Fusarium acuminatum.The highest frequency of fungal contamination was found in 9 strains.2 Species identification of contaminated fungi Based on the characteristics of colony and micromorphology,9 strains of contaminated fungi with high contamination rate were identified by molecular biology,and 5 strains of specific species were identified,they are: Clonostachys rosea、Cladosporium sphaerospermum、Penicillium rubens,fusacuminatum and Gillus ochaceus.The morphological characteristics and its harm to tissue culture seedlings were described.3 Screening agents for preventing and controlling polluting bacteria indoors Potato tissue cultured seedlings contaminated fungi include Clonostachy roseas,Penicillium,Mucor racemosu.11 kinds of fungicides were used for indoor virulence testing.The results showed that 70% thiophanate-methyl,250 g/L azoxystrobin and 3%Zhongshengmycin were used,50% boscalid,40% myclobutanil and 80%carbendazim have strong inhibitory effects on the growth of pathogenic bacteria.Among them,3% Zhongshengmycin,250 g/L azoxystrobin and 40% Myclobutanil are more virulent.