Caracterização cultural e micromorfológica de actinobactérias do semiárido nordestino em diferentes níveis de cobertura vegetal

Abstract

Actinobacteria are Gram-positive bacteria, rich in guanine and cytosine in their DNA, forming complex structures such as spores and spore chains. They provide important ecosystem services which indirectly or directly contribute to edaphic formation and maintenance. Moreover, they are highly exploited sources of secondary metabolites. These bacteria are present in the Brazilian northeastern semiarid and their cultural and micromorphological characteristics are quite variable. However, these characteristics are a key factor for the classification of this phylum. Thus, the objective of the present study was to characterize the bacterial culture, identify genera, analyze diversity and generate photographic content focusing on the differences in 46 strains of actinobacteria from three areas with different levels of plant cover in the Médio Jaguaribe region (CE) ). The characterization of the culture due to the color of the aerial and reverse mycelium and the texture of the colonies showed the heterogeneity of the strains, presenting the predominance of gray and white color in the mycelia and velvety texture (65%). The nine genera identified through microscopic analysis were: Actinomadura, Arthrobacter, Micrococcus, Mycobacterium, Nocardia, Micromonospora, Thermomonospora, Streptosporagium and Streptomyces. Based on the morphological parameters of the color of the aerial and reverse mycelium, aspect of colony formation and micromorphology of the spore chain, the chromogenic and textural diversity was evidenced, and the predominance of the genus Streptomyces. These characteristics, together with the image collection, can assist and serve as a basis for ecological and bioprospecting studies on these microorganisms.