Análise comparativa de glicanas e quitinas da parede celular de espécies de Trichoderma e a relação desses polissacarídeos no pareamento com fitopatógenos

Abstract

The fungal cell wall is responsible for intracellular protection, shape and communication. Its varieties of functions are related to its composition. The cell wall is composed primarily of polysaccharides and proteins. Among the polysaccharides most important to the fungal cell are glucans and chitins, and the amounts of these polysaccharides may vary according to each species and genus of fungi. The fungi of the genus Trichoderma are among the most studied currently, due to their importance for agriculture. It is known mainly for its mechanism of combat to phytopathogens mainly Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium oxysporum. This mechanism of attack to phytopathogens is closely linked with the composition of the fungal wall, therefore the need to study the composition of the wall of Trichoderma and phytopathogens. In this work the species will be studied the composition of the cell wall of Trichoderma harzianum, T. harzianum mutant (ΔEPL1), T. asperellum and T. reesei. The fungi were cultivated in BDA medium for 7 days, where they were grown alone and in antagonism with phytopathogens. Cell wall polysaccharides were extracted and fractionated from Trichoderma mycelium. The analysis of the wall sugars were performed in HPLC, where glucose and N-acetylglucosamine, respectively, glucans and chitins were detected. In addition, analyzes were performed for the detection of glucans and chitin directly by glucox and DMAB. Total sugars and proteins were also dosed, in addition to the enzymes glucanases and chitinases. It was observed that the fungi Trichoderma harzianum and T. asperellum have an amount of glucans and chitin higher than the fungus Trichoderma reesei, which can be explained by the fact that T. reesei possesses a low mycorrhizal activity when compared with other Trichoderma species. When the Trichoderma walls were analyzed in contact with phytopathogens, it was observed that the amount of sugars and their enzymatic composition increased significantly, and it can be concluded that the change in composition of the fungal wall reveals that it is very dynamic and is directly related to the process of myoparasitism.