Changes in Root Bacterial Communities Associated to Two Different Development Stages of Canola (Brassica napus L. var oleifera) Evaluated through Next-Generation Sequencing Technology

Abstract

Crop production may benefit from plant growth-promoting bacteria. The knowledge on bacterial communities is indispensable in agricultural systems that intend to apply beneficial bacteria to improve plant health and production of crops such as canola. In this work, the diversity of root bacterial communities associated to two different developmental phases of canola (Brassica napus L.) plants was assessed through the application of new generation sequencing technology. Total bacterial DNA was extracted from root samples from two different growth states of canola (rosette and flowering). It could be shown how bacterial communities inside the roots changed with the growing stage of the canola plants. There were differences in the abundance of the genera, family, and even the phyla identified for each sample. While in both root samples Proteobacteria was the most common phylum, at the rosette stage, the most common bacteria belonged to the family Pseudomonadaceae and the genus Pseudomonas, and in the flowering stage, the Xanthomonadaceae family and the genus Xanthomonas dominated the community. This implies in a switch in the predominant bacteria in the different developmental stages of the plant, suggesting that the plant itself interferes with the associated microbial community.

Root growth dynamics inside and outside of soil biopores as affected by crop sequence determined with the profile wall method

“…No significant effects of crop sequence shown on shoot growth parameters (SPAD value, LAI, and biomass yield) and final grain yield suggest that the expected biopore effects on overall crop performance might be more vividly shown under stress condition (Volkmar 1996;Gaiser et al 2012). More importantly, understanding 4 Root length (km m −2 ) inside (a) and outside (b) of biopores beneath 45 cm of soil depth as affected by crop sequence (chicorywheat and tall fescue-wheat) and growth stage (tillering, booting, anthesis, and milk) in 2012.…”

“…Recently, a novel visual approach has also shown that roots elongating inside biopores cross the pore walls in deep soil horizons (Athmann et al 2013), thus can re-explore the bulk soil. Improved water (Gaiser et al 2012) and N uptake (Volkmar 1996) by wheat as a function of pore-assisted root growth suggest that plants are capable of utilizing subsoil resources when accessible . Increased plant P availability (Barej et al 2014) and microbial activity (Kuzyakov et al 2007;Uksa et al 2014) in zones adjacent to large sized biopores also indicate that the biologically created pores might be hotspots for nutrient acquisition (Kautz et al 2013a).…”

Oilseed rape cultivation increases the microbial richness and diversity in soils contaminated with cadmium

“…Hong et al (2015) found that the variable degree of heavy metals in the soil in iron mining areas increased bacterial alpha diversity and changed the dominant genera. Cadmium pollution of soil reportedly can change the taxonomic diversity and functionality of the microbial communities, and further affect soil quality and plant growth (de Campos et al 2013;Hill et al 2000;Li et al 2014;Tipayno et al 2011).…”

“…Many studies have verified that some certain oilseed rape varieties had tolerance of Cd and possessed the ability to accumulate it (Dechun and Wong 2002;Ru et al 2004;Su et al 2009). However, studies regarding interactions between microorganisms and B. napus in soil polluted with heavy mental are still at a preliminary stage (Germida et al 1998;Dunfield and Germida 2003;Farina et al 2012;Croes et al 2013;de Campos et al 2013). So far, no study has revealed the effects of varying Cd levels on both bacterial and fungal diversity in the soil cropped with oilseed rape via NGS technology.…”

Complete genome sequence of Paenibacillus riograndensis SBR5T, a Gram-positive diazotrophic rhizobacterium

“…Bacterial communities can be characterized by metagenomics approaches as e.g. applied to monitor changes of root bacterial communities associated to two different development stages of canola (Brassica napus L. var oleifera; de Campos et al, 2013). Studies focusing on isolation of plant growth-promoting bacteria are also often performed, e.g.…”