Nitrogen Fixing and Phosphate Mineralizing Bacterial Communities in Sweet Potato Rhizosphere Show a Genotype-Dependent Distribution

Abstract

We hypothesize that sweet potato genotypes can influence the bacterial communities related to phosphate mineralization and nitrogen fixation in the rhizosphere. Tuberous roots of field-grown sweet potato from genotypes IPB-149, IPB-052, and IPB-137 were sampled three and six months after planting. The total community DNA was extracted from the rhizosphere and analyzed by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) and quantitative real-time PCR (qPCR), based on the alkaline phosphatase coding gene (alp gene) and on the nitrogenase coding gene (nifH gene). The cluster analysis based on DGGE showed that plant age slightly influenced the bacterial community related to phosphate mineralization in the rhizosphere of IPB-137, although it did not affect the bacterial community related to nitrogen fixation. The statistical analysis of DGGE fingerprints (Permutation test, p ≤ 0.05) showed that nitrogen-fixing bacterial community of IPB-052 statistically differed from genotypes IPB-149 and IPB-137 after six months of planting. The bacterial community of IPB-137 rhizosphere analyzed by alp gene also showed significant differences when compared to IPB-149 in both sampling times (p ≤ 0.05). In addition, alp gene copy numbers significantly increased in abundance in the rhizosphere of IPB-137 after six months of planting. Therefore, plant genotype should be considered in the biofertilization of sweet potato.

Metagenomic Insights into Rhizospheric Microbiome Profiling in Lentil Cultivars Unveils Differential Microbial Nitrogen and Phosphorus Metabolism under Rice-Fallow Ecology

“…It is evident from this study that genotypes have a diminutive contribution towards shaping microbiome diversity [6]. On the contrary to that, previous studies reported a significant role of genotypes in selecting specific microbial groups in the rhizosphere [10,34,35]. Considering the functional profiling of a rhizosphere microbiome, our study has identified redundancy in the metabolic capacities of the bacterial communities with dominance of genes related to the metabolism and genetic processing categories.…”

“…Several host–genotype-specific rhizospheric microbial community developments have been studied in many crops viz. peanut [ 6 ], soybean [ 11 ], sweet potato [ 35 ], tomato [ 44 ], rice [ 45 ], mulberry [ 46 ], and maize [ 47 ]. Most of the studies revealed that plant genotype plays a very small but significant role in shaping rhizospheric microbial association under diverse agroecological situations [ 48 , 49 ] in order to mitigate different stress conditions like phosphate starvation [ 50 ], nutrient mobilization [ 51 ], and plant growth promotion [ 52 ].…”

“…Earlier studies with a cultivar response towards the microbial community structure and diversity in peanut [ 6 ] and maize [ 34 ] revealed that cultivars differing in N use efficiency or BNF had a differential microbiome community with diverse enzymatic activity. In sweet potato, the composition of phosphate-mineralizing bacterial community exhibited significant diversity depending on genotypic differences [ 35 ]. Similarly, different soybean genotypes recruited diverse Rhizobium colonies and mildly tuned rhizosphere microbiome assembly [ 11 ].…”

Seed Biopriming Using Rhizobacterial Isolated Mixture on Increasing Growth and Yield of Shallots (Allium ascalonicum L.)

“…This type of bacteria has advantages in addition to promote plant growth, it is also able to protect plants from various plant disease infections. Several research results indicate that rhizobacteria are able to synthesize growth hormones, including IAA, gibberellin, and cytokinins [6], [7], [8], fix nitrogen [9], [10], [11] and dissolve phosphate [6], [12]. Meanwhile, as biological controllers for pathogens, rhizobacteria are able to produce compounds or metabolites such as antibiotics, HCN, siderophores, and secrete various hydrolytic enzymes that can degrade pathogenic cells [13], [14], [15].…”

Genetic Diversity of Soil Bacteria

“…A research paper by Marques and colleagues reports that sweet potato genotypes and their growth stage influence rhizosphere bacterial composition, in particular that of microbial groups involved in phosphate mineralization and nitrogen fixation, both playing a fundamental role in plant nutrition processes [8].…”