Histological examination of endophytic Chaetomium cochliodes Palliser fungus localization in healthy tissues of agricultural crop roots

Abstract

The ability was investigated of the Chaetomium cochliodes fungus to penetrate the healthy tissues of agricultural crop roots. It is well-known that endophytic fungi can exist in plant tissues for a long time without any sign of their presence and only become active under adverse environmental conditions. Localization of endophytic fungus mycelia within the macroorganism was revealed using histological methods. Seeds of wheat, barley, rye, triticale, buckwheat, maize, sunflower, soybean and flax were inoculated with the saprotrophic fungus C. cochliodes and grown in a vegetation experiment. Thin sections of the roots and plant root hairs were painted with an aniline blue lactic acid solution to visualize fungal mycelia and, in some cases, spores. Some small hyphae were found inside rhizodermal cells. The presence of fungal structures and their localization in healthy tissues of the roots of cereals, legumes and industrial crops indicated the endophytic ability of C. сochliodes. At the same time, an increase in the succinate dehydrogenase activity was observed in the roots of plants inoculated with the fungus for wheat (by 1.2 times), barley (by 3.2 times), rye (by 3.7 times), triticale (by 3.4 times), maize (by 3.2 times), sunflower (by 1.6 times), soybeans (by 2.9 times) and buckwheat (by 1.5 times). Additional evidence of the formation of active endophytic symbiotic systems was the increasing activity of succinate dehydrogenase with the simultaneous penetration of C. cochliodes into healthy plant roots. The studies conducted deepen the understanding of the biology of the relationship between a macroorganism and an endophytic fungus.