Research In Population Structure Of Non-Fusarium Graminearum Strains From Maize In China

Corn is one of the major food crops and corn industry plays an important role in agriculturl production China. Maize ear rot caused by Fusarium species is one of the important disease in maize yield loss in our country. Maize ear rot is widely distributed in the main maize production areas in China, and it is influenced by the agricultural ecological environment, meteorological condition, cropping system and field management. Field loss caused by Maize ear rot is usually 5%-10%, and when it is seriously can reaches 40%. With the enlargement of the corn planting area in China, the danger of maize ear rot is increases year by year. Currently, The pathogens which can cause maize ear rot mainly include Fusarium, Penicillium, Trichoderma, Aspergillus, Alternaria, Rhizopus, etc. Among them, Fusarium species is the one which have the most widely distributed and the largest influence, and F.graminearum and F. verticillioides are the main species of them.Fusarium species can infect wheat, rice, corn and other cereal grain crops, is an economically important plant pathogenic fungus in China and throughout theworld. The pathogen can produce different kinds of mycotoxins during infecting plants. Fusarium mycotoxins can be divided into eight species:Trichothecenes, Zearalenone, Fumonisins, Fusarin C, Moniliformin, Enniatins, Beauvericin and Fusaproliferin. Trichothecenes, Zearalenone and Fumonisins are most common Fusarium mycotoxins. These toxins can directly endangering human and animal health when they are introduced into the food chain with food and feed processing, and then cause food safety issues. Fusarium species are widely distributed, the population structure analysis of the pathogen is very important for the plant-pathogen interaction research, pathogen and mycotoxins control, and also will contribute to the management of Fusarium disease and food security. In this study, we studied the population structure, pathogenicity and mycotoxin productivity of non-Fusarium graminearum from corn in China. The main results are as follows.1. Clear the population structure of non-Fusarium graminearum on maize in chinaDiseased ears of corn from 148 sampling sites in 22 provinces were collected from corn fields in China. In total,905 Fusarium strains were isolated and further purified through single spore isolation. The combination of traditional morphological classification and molecular methods were employed for the identification of these strains in the current study. Seventeen Fusarium species were identified:F. verticillioides, F. proliferatum, F. oxysporum, F. equiseti, F. fujikuroi, F. subglutinans, F. temperatum, F. poae, F. kyushuense, F. solani, F. boothii, F. andiyazi, F. anthophilum, F. lacertarum, Fmusae, F. sacchari, F. commune. Clear the species and geographic distribution of non-Fusarium graminearum onmaize in china. The result shows that F. verticillioides is the dominant species in non-Fusarium graminearum on maize in china. Besides, F. commune, F. temperatum, F. kyushuense, F. lacertarum, F. boothii, F. andiyazi and F. sacchari are new record species from corn in China.2. The pathogenicity of different non-Fusarium graminearum strains were differenceThe pathogenicity of sixteen non-Fusarium graminearum strains from different geographical and host origins was tested on wheat and corn, respectively. The results indicated that the pathogenicity of different non-Fusarium graminearum strains were difference, but less aggressive. The symptoms only shown in the inoculated spikelets on susceptible wheat cultivar Annong8455. The fungus can’t spread beyond the inoculated spikelets. No significant difference was found on the pathogenicity tests on corn cultivars Zhengdan958.3. The type and quantity of mycotoxin produced by different non-Fusarium graminearum strains was significant different.The mycotoxin metabolism profiles of twenty-nine Fusarium strains were assayed. The results showed that all the tested Fusarium graminearum clade strains can produce type B trichothecenes (DON、4-ANIV、3-ADO、15-ADON、NIV). However, type B trichothecenes were only produced by F. kyushuense, F. lacertarum and F. poae in the non-Fusarium graminearum clade strains, and NIV accounted for a higher proportion. The quantity of mycotoxin produced by different strains was significant different.