Analysis of soil bacterial communities associated with genetically modified drought-tolerant corn

Abstract

It is well known that plant species influence the composition and activity of the rhizosphere microbiota through the modification of physicochemical characteristics of the soil. Since microorganisms play a fundamental role in soil processes and plant growth, it is important to understand plant-microbe interactions, including how genetically modified (GM) plants can affect the soil microbial communities. This study aimed to investigate the diversity of the soil bacterial community associated with the root of GM drought-tolerant corn (Zea mays L.) bearing the gene encoding the transcription factor Hahb4 of sunflower (Helianthus annuus L.). Bacterial diversity was analyzed by amplicon sequencing of the 16S rRNA gene in an experiment under controlled conditions using soil from two agricultural sites in Argentina (Río Cuarto and Inés Indart) and two irrigation regimes (30% and 100% of soil field capacity). Results showed differences in microbial diversity between the two soils. However, under the conditions tested, the GM drought-tolerant corn line did not affect the α or β diversity at the different irrigation regimes in comparison with the parental wild-type corn line. The main phyla composing the bacterial community were similar in both soils. Several genera were significantly more represented in the drought condition than in the condition with good irrigation. Drought had less effect on the bacterial diversity of Inés Indart soils than on that of Río Cuarto soils. Results showed no undesirable impact of the GM drought-tolerant corn expressing the Hahb-4 gene on the rhizosphere bacterial community under the experimental conditions used in this study.