Enhancement of maize growth and alteration of the rhizosphere microbial community by phosphate-solubilizing fungus Aspergillus aculeatus P93

Authors: YIN, ZHONGWEI - Chinese Academy Of Agricultural Sciences; FAN, BINGQUAN - Chinese Academy Of Agricultural Sciences; Roberts, Daniel; CHEN, SANFENG - China Agricultural University; SHI, FACHAO - Chinese Academy Of Agricultural Sciences; Buyer, Jeffrey; JIANG, HONMEI - Chinese Academy Of Agricultural Sciences

Submitted to: Journal of Agriculture Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2017
Publication Date: 10/1/2017
Citation: Yin, Z., Fan, B., Roberts, D.P., Chen, S., Shi, F., Buyer, J.S., Jiang, H. 2017. Enhancement of maize growth and alteration of the rhizosphere community by phosphate-solubilizing fungus Aspergillus aculeatus P93. Journal of Agriculture Biotechnology. https://dx.doi.org/10.20936/JAB/170201.
DOI: https://doi.org/10.20936/JAB/170201.

Interpretive Summary: Sustainable methods for the production of maize and other crops need to be developed. Use of chemical fertilizers in crop production can introduce damaging levels of phosphorus into the environment. A potential solution is to develop phosphorus-solubilizing microorganisms that help provide adequate quantities of phosphorus to plants in combination with reduced quantities of chemical fertilizer or no fertilizer. In this study we showed that the beneficial fungus Aspergillus aculeatus P93, when applied as a seed treatment, significantly improved maize plant growth and soil available phosphorus compared to the nontreated control. We also showed that treatments containing this fungus altered the maize rhizosphere community. These experiments identified this fungus as an excellent candidate for development to be used in alternative strategies for fertility management of maize and other crops. This is due to the ability of treatments containing this fungus to directly improve plant phosphorus nutrition and/or potentially improve plant phosphorus nutrition through alteration of the rhizosphere microbial community. This information will be useful to scientists devising alternative methods for fertility management in crop production.

Technical Abstract: Over-application of phosphatic fertilizers has adversely impacted agricultural sustainability and the environment in China and other regions of the world resulting in the need for alternative strategies, such as the use of phosphate-solubilizing microbes. Aspergillus aculeatus P93, isolated from the rhizosphere of maize grown in a calcareous soil, excreted several organic acids and the plant-growth-hormone indole-3-acetic acid (IAA) into Pikovskaya’s broth. P93 also acidified and solubilized phosphorus from insoluble tricalcium phosphate and rock phosphate in Pikovskaya’s broth. P93 applied as a seed treatment increased plant dry weight of maize grown in non-amended calcareous soil or this soil amended with rock phosphate in greenhouse pot studies. P93 also increased soil available phosphorus in the non-amended and amended soil and increased total plant phosphorus of maize grown in the non-amended soil. Significant increases in several organic acids were detected in both the non-amended and amended soil in association with P93 in these greenhouse pot studies. DGGE-based analysis of maize rhizosphere demonstrated alterations in microbial community structure due to the introduction of P93. Studies reported here indicate that seed treatments containing P93 are capable of promoting maize growth in a calcareous soil. Plant-growth promotion by P93 is likely due, at least in part, to production of IAA and increased phosphorus availability resulting from excretion of organic acids into, and the resulting acidification of, this soil. However, consideration must also be given to the role of the altered rhizosphere microbial community resulting from application of treatments containing P93.