Bacterial and fungal diversity from the rhizosphere of plants wildly growing in agricultural soil under unfavourable environmental conditions

Rhizospheres commonly harbor a great diversity of microorganisms, many of which interact with the plants and soil, favouring plant nutrient acquisition and/or contributing to the recycling of organic compounds and/or taking part in symbiotic associations and therefore having global benefits to plant ecosystems. However, when it comes to agriculture, frequently, there is a tendency to remove any plant different from that of the species being cultivated. This work aimed to display the microbial communities associated with the roots of native vegetation wildly growing in soil devoted to agricultural crops. Thus, high-throughput sequencing of culture-independent marker genes was performed for bacteria and fungi from these habitats. Rhizospheres were collected from several sampling sites within the same agricultural area in dry land after a period of prolonged environmental high temperatures.

With respect to bacteria, results revealed a number of OTUs ranging from 3,210 to 3,266, with the relatively most abundant identified families and/or genera being Bacillus, Caulobacter, Domibacillus, Erwiniaceae, Glycomyces, Lechevalieria, Massilia, Micrococcaceae, Paenarthrobacter, Promicromonospora, Pseudomonas, Rhizobiaceae, Sphingomonas, Streptomyces, and Terribacillus. With respect to fungi, the results revealed a number of OTUs ranging from 963 to 973, with the relatively most abundant identified families and/or genera being Alternaria, Aspergillus, Aureobasidium, Chaetomium, Cladosporium, Coniothyrium, Didymellaceae, Entoloma, Fusarium, Macrophomina, Monosporascus, Poculum, and Sclerostagonospora. All of them, along with the totality of the substantial minority species, can contribute with their activity to the sustainability of the agricultural soil. Information on the composition of the rhizosphere bacterial and fungal communities allows for a deeper understanding of their potential functions and, eventually, of their beneficial effects on plant growth under challenging environmental conditions.