Biotechnological potential of endophytic bacteria of bamboo Guadua sp. for promotion of growth of micropropagated yam plants (Dioscorea rotundata Poir)

Abstract

Endophytic microorganisms have a wide genetic diversity, being very useful for agriculture, for producing growth regulators and making nutrients available to plants. In this context, this research aimed to isolate and characterize endophytic bacteria from bamboo Guadua sp., in order to evaluate the use of these microorganisms in promoting plant growth in yam plants (Dioscorea rotundata Poir). For this, the macromorphological characteristics of bacterial colonies were studied: shape, borders, consistency, color, brightness. Micromorphological analysis was performed using the Gram method. Biological tests of phosphate solubilization, biological nitrogen fixation and indole acetic acid production were carried out, where the bacteria with the best results were selected to assess the potential to promote the growth of white yam plants. The growth experiment consisted of four treatments: a control (without inoculation) and three treatments with endophytic bacteria, inoculated in pre-acclimated yam plants. Each treatment consisted of 6 repetitions with 5 plants per plot, totaling 30 plants per treatment. The colonies showed similar patterns of morphological characteristics for the three collection sites, with characteristics such as “circular” shape, “entire” border, “creamy” consistency, “brown” color and “bright” shine. We observed that 39.1% of the bacteria were able to perform phosphate solubilization, 61.9% performed atmospheric nitrogen fixation and 26.9% performed indole acetic acid synthesis. The results showed that the endophytic bacteria isolated from Guadua sp. did not promote dry matter accumulation of white yam plants after 45 days of cultivation in a nursery.