Structure of rhizosphere mycocomplexes and phyloplanes of cultural peanuts
Relevance. Peanut seeds are rich in oils, protein, carbohydrates, vitamins and flavonoids, therefore they are widely used in the production of food, feed, biodiesel, as well as in medicine. When cultivating peanuts, the problem of reducing the yield and sometimes the quality of seeds necessarily arises due to the impact of phytopathogenic microscopic fungi, and the main factors in the transmission of the infectious principle are soil and plant residues. The plant protection system should be based on knowledge of the structure of mycocomplexes of the rhizosphere and phylloplane. Methods. On a typical black soil on a natural infectious background in Belgorod (Russia), a sample of cultural peanuts V-2012 (Vietnam) from the collection of the Department of Biotechnology and Microbiology of the Institute of Pharmacy, Chemistry and Biology of the National Research University "BelSU" was studied. The species composition of microscopic fungi in the peanut rhizosphere was analyzed in comparison with fallow soil (control), which was found by seeding soil dilutions and leaf samples on dense nutrient media, followed by identification to species. Results. Compared with the control soil, the mycocomplex of the peanut rhizosphere (the Shannon index value at the level of 2.5 and 2.7 in the rhizosphere and control, respectively) was characterized by a lower degree of diversity and the degree of similarity of soil samples was high (the Jaccard coefficient was 50%), which means that that the cultivation of peanuts has little effect on the composition and structure of a typical black soil. In the peanut rhizosphere, a decrease in the frequency of occurrence of the phytopathogenic species F. oxysporum was observed, which may be associated with an increase in the rank in the mycocomplex of the mycophilic species T. lignorum. Aspergillus ochraceus, A. terreus, A. ustus, Candida albicans, Curvularia lunata, Fusarium oxysporum, Trichothecium roseum species were found to be sensitive to peanut cultivation. Peanut leaf spot was caused annually by the species Alternaria alternate, which can lead to a decrease in seed productivity up to 80%.