Evaluación de la expresión de los genes involucrados en la biosíntesis de lipopéptidos antimicrobianos en Bacillus megaterium mediante RT-qPCR.

Abstract

One of the main problems of agriculture is to control phytopathologies, due to this factor, there is a need to apply biological agents as pest controllers to prevent the use of chemicals. Therefore, in the present research was performed to evaluate the expression of genes involved in antimicrobials lipopeptides’ biosynthesis in B. megaterium by using RT-qPCR. The relative gene expressions (RGE) evaluated were the FEND and ITUDI genes which encode for fengicines and iturines respectively. The first stage consisted of antagonist tests of B. Megaterium vs. Alternaria sp. and Botrytis sp., performed for nine days, evidencing that the bacteria controlled growth of both pathogens. To corroborate this result, the second stage consisted of various molecular tests, evaluated the expression of FEND and ITUDI genes during nine days; which were taken from the dual microbial culture previously discussed, resulting in the expression of the FEND gene of Bacillus megaterium vs. Alternaria sp. increased by 20,16 times and against Botrytis sp. increased 3,20 times, both at day 5. In the same way the bacteria were put into a fermentation process, in different times, giving an increase of 95,14 and 18,70 times more than the normal expression of the FEND and ITUDI genes respectively, concluding that there is an actual increase in the genetic expression when Bacillus Megaterium grows next to a pathogen, as previously reported. Thus, the growth of Bacillus Megaterium in fermentation conditions increases the genetic expression even more.