Effects of Plant Genotype and Growth Stage on the Betaproteobacterial Communities Associated with Different Potato Cultivars in Two Fields

Abstract

Bacterial communities in the rhizosphere are dynamic and susceptible to changes in plant conditions. Among the bacteria, the betaproteobacteria play key roles in nutrient cycling and plant growth promotion, and hence the dynamics of their community structures in the rhizosphere should be investigated. Here, the effects of plant cultivar, growth stage, and soil type on the communities associated with potato cultivars Aveka, Aventra, Karnico, Modena, Premiere, and Désirée were assessed for two different fields containing sandy soil with either a high or low organic compound content. Thus, bacterial and betaproteobacterial PCR-denaturing gradient gel electrophoresis analyses were performed to analyze the effects of plant cultivar and growth on the rhizosphere community structure. The analyses showed that in both fields all cultivars had a rhizosphere effect on the total bacterial and betaproteobacterial communities. In addition, the plant growth stage strongly affected the betaproteobacterial communities in both fields. Moreover, the community structures were affected by cultivar, and cultivars differed in physiology, as reflected in their growth rates, root development, and estimated tuber starch contents. Analyses of betaproteobacterial clone libraries constructed for two selected cultivars (one cultivar that produced low-starch-content tubers and one cultivar that produced high-starchcontent tubers), as well as bulk soil, revealed that the rhizospheres of the two cultivars selected for specific bacteria, including plant-growth-promoting bacteria, such as Variovorax and Achromobacter spp. In addition, quantitative PCR-based quantification of the Variovorax paradoxus-specific functional gene asfA (involved in desulfonation) indicated that there were clear potato rhizosphere effects on the abundance of this gene. Interestingly, both cultivar type and plant growth stage affected the community under some circumstances.

13C pulse‐labeling assessment of the community structure of active fungi in the rhizosphere of a genetically starch‐modified potato (Solanum tuberosum) cultivar and its parental isoline

“…Earlier field observations did not reveal significant differences in bacterial or fungal communities between this GM cultivar and its parental cultivar (Hannula et al, 2010;Inceoglu et al, 2010), although differences between the two were greatest at the stage of senescence, probably as a result of differences in rhizodeposition (Weinert et al, 2009). Moreover, comparing the GM cultivar only with its parental variety and neglecting intraspecific variation in carbon distribution can cause false significant results, especially when evaluating potential risks of GM crops (Hannula et al, 2010).…”

Bacterial populations in juvenile maize rhizospheres originate from both seed and soil

“…The advent of sensitive molecular fingerprinting and affordable next generation sequencing technologies has sparked a renaissance in rhizosphere research, with many new studies concerning the bacterial diversity present in maize rhizospheres (Bakker et al 2015;Bouffaud et al 2012;Castellanos et al 2009;Dalmastri et al 1999;Peiffer and Ley 2013;Peiffer et al 2013), Arabidopsis rhizospheres (Bulgarelli et al 2012;Lundberg et al 2012;Micallef et al 2009) and the rhizospheres of other important plant species (Costa et al 2006;Edwards et al 2015;Garbeva et al 2008;Germida and Siciliano 2001;Inceoglu et al 2010;van Overbeek and van Elsas 2008;Weinert et al 2011).…”

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

“…However, the influence of B. napus plays a leading role on microbial structure, which has the ability to remedy the loss of richness and diversity caused by Cd pollution. We suspect that this is due to the so called hostgenotype-dependent differences in patterns of microbial associations (Inceoglu et al 2010;Inceoglu et al 2011). The remedial effect of B. napus seems largely independent with the degree of Cd pollution.…”

“…That is to say, when soils cropped with oilseed rape, the species richness, diversity, and evenness of bacterial communities in Cd-contaminated soil are higher than the unpolluted and idle soil. This is mainly because substrates secreted by plant roots performed a direct effect on microbial richness (Inceoglu et al 2010). In the Venn diagrams (Figs.…”