Analysis of soil bacterial communities associated to genetically modified drought tolerant corn plants

IBARRA, JOSE G.; LOPEZ NANCY I.; GODEAS ALICIA M.; COLOMBO, ROXANA P.

San Miguel deTucuman

Congreso; SAMIGE; 2017

Asociación Argentina de Microbiología General

The use of genetically modified (GM) plants have been developed worldwide since the last 30 years, these crops dominated the agricultural production systems in Argentina in a few years. It is known that different plant species influence the composition and activity of the rhizosphere microbiota through the modification of physicochemical factors in soil. Since microorganisms play a fundamental role in environmental processes, soil fertility and plant growth and health, it is of the utmost importance to understand plant-microorganism interactions, including how GM plants can affect the soil microbial communities.The aim of this work was to analyze the bacterial community diversity associated to GM maize plants resistant to drought stress.In order to analyze whether GM plants impact on the soil bacterial community, experiments under controlled conditions were carried out. Plants were grown in pots with soil from Río Cuarto (RC) and Inés Indart (II) in a growth chamber for 60 days. Two lines of maize were used, one GM that over express the Hahb4 gene and the wild-type line (B104). Soil moisture was maintained at 100 or 30% of soil field capacity. Bacterial diversity of soil samples was analyzed by amplicon sequencing of the16S ribosomal RNA gene V1-V3 region using Illumina MiSeq.The two analyzed soils were different in terms of diversity but not differences in diversity were found by comparing treatments within soils. In II there were no differences in  diversity between treatments, whereas in RC we found differences when comparing the samples with different corn line.The composition of the major groups was similar between soils, with Proteobacteria being the most represented with around 30% of the total reads, followed by Acidobacteria (17%) and Planctomycetes and Verrucomicrobia (10%) each one.In all samples the predominant genus was Acidobacterium with 14 to 20% of the reads and most genera had a relative abundance of 0.01-0.1%. Analysis were performed to determine bacterial genera affected by each irrigation condition and corn line. We found 23 genera significantly affected (p