Caracterización molecular de bacterias rizosféricas asociadas a Echinocactus platyacanthus en invernadero y silvestres

The sweet biznaga (Echinocactus platyacanthus) is an endemic cactus of Mexico characterized by its slow growth and low rate of reproduction, which together with a high collection pressure, places wild populations at risk. Currently, the study of bacterial communities associated with cactus is scarce and it is unknown what cultivable bacteria are present in the rhizosphere of sweet biznagas that grow in nature and those that are grown in nurseries. For this study rhizospheric material was collected from wild and cultivated biznagas, in addition to non-rhizospheric soil. A total of 268 morphotypes were isolated and grouped into 41 different ribotypes by RFLP. Representatives of each ribotype were identified by sequencing the 16S rRNA gene. The cultivable fraction of the bacterial community associated with E. platyacanthus is mainly composed of members of the genera Bacillus (21 strains), Pseudomonas (6 strains), Stenotrophomonas (4 strains), Paenibacillus (2 strains), Brevibacterium, Staphylococcus and Cutibacterium (1 strain, each one), with Bacillus genus being the predominant. The genera Bacillus and Pseudomonas have been previously reported for carrying out beneficial activities for the plants with which they are associated.