The rhizosphere is of central importance for plant nutrition, health and quality. Microorganism-driven ecosystem functioning and nutrient cycling occur here. A multitude of treatments are assumed to affect the growth and physiology of the plant, but the impacts on the structural and functional diversity of microbial communities in the rhizosphere is poorly understood.
A field experiment was conducted to evaluate the influence of different cultivars, trellising treatments and plant developmental stage on sweet potato rhizosphere microbial communities. This study was conducted in high tunnel houses at S&B farm at Eufaula AL in 2015. The study was arranged in a 2 x 3 factorial design with a bed size was 16’ x 2’ and sample were replicated three times. The microbial communities of the samples were identified using MiSeq illumina DNA sequencing with primers for bacterial and fungal identification. Subsequent bioinformatics analysis was carried out to assess taxonomic, alpha, and beta diversity indicators.
Results/Conclusions
In contrast to cultivar and trellising, plant developmental stage showed a significant impact on the sweet potato rhizosphere microbial community. In cultivar Carver microbial richness was significantly high (level of significance 0.005) than cultivar TU1892. No significant difference was found in trellising (level of significance 0.32) and non-trellising treatment (level of significance 0.86). Moreover, in maximum leaves plant developmental stage the microbial diversity, richness and evenness were highest than tuber root initiation and harvest time. The genus Bacillus was the most abundant bacteria in the sweet potato rhizosphere of all treatments and were increased significantly in plant growth stage and it helps plant for phosphorus and potassium solubilization and protects plant from plant pathogens. Nitrogen fixing bacteria Rhizobium, Azospirillum, Bradyrhizobium, Mesorhizobium were significantly increased in plant growth stages. Nitrifying bacteria Nitrosomonas and Nitrosococcus were significantly decreased in trellising treatment. However, Nitrosomonas and Nitrobacter significantly increased in plant growth stage. For fungi, result showed that plant developmental stage had a significant influence on the fungal community of sweet potato rhizosphere. Fungal richness, evenness and diversity was high in cultivar1892 than cultivar Carver and the level of significance was 0.04. For, fungal diversity, richness and evenness were found more in non-trellising treatment (P value= 0.00001) and the plant developmental stage. This indicates that plant developmental stage had a significant effect on the microbial community on sweet potato rhizosphere.