Phosphorus-Solubilizing Capacity of Mortierella Species Isolated from Rhizosphere Soil of a Poplar Plantation

Yue Sang; Long Jin; Rui Zhu; Xing-Ye Yu; Shuang Hu; Bao-Teng Wang; Hong-Hua Ruan; Feng-Jie Jin; Hyung-Gwan Lee

doi:10.3390/microorganisms10122361

Phosphorus-Solubilizing Capacity of Mortierella Species Isolated from Rhizosphere Soil of a Poplar Plantation

Microorganisms. 2022 Nov 29;10(12):2361. doi: 10.3390/microorganisms10122361.

Authors

Yue Sang¹, Long Jin¹, Rui Zhu¹, Xing-Ye Yu¹, Shuang Hu¹, Bao-Teng Wang¹, Hong-Hua Ruan¹, Feng-Jie Jin¹, Hyung-Gwan Lee²

Affiliations

¹ College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China.
² Cell Factory Research Centre, Korea Research Institute of Bioscience & Biotechnology (KRIBB), Daejeon 34141, Republic of Korea.

Abstract

Phosphorus is one of the main nutrients necessary for plant growth and development. Phosphorus-dissolving microorganisms may convert insoluble phosphorus in soil into available phosphorus that plants can easily absorb and utilize. In this study, four phosphorus-solubilizing fungi (L3, L4, L5, and L12) were isolated from the rhizosphere soil of a poplar plantation in Dongtai, Jiangsu Province, China. Phylogenetic analysis based on the internal transcribed spacer (ITS) and large subunit (LSU) of the ribosomal DNA sequences showed that the ITS and 28S sequences of isolates were the most similar to those of Mortierella. Morphological observation showed that most colonies grew in concentric circles and produced spores under different culture conditions. These results and further microscopic observations showed that these isolated fungi belonged to the genus Mortierella. Pikovskaya (PKO) medium, in which tricalcium phosphate was the sole phosphorus source, was used to screen strain L4 with the best phosphorus-solubilizing effect for further study. When the carbon source was glucose, the nitrogen source was ammonium chloride, the pH was 5, and the available phosphorus content was the highest. By exploring the possible mechanism of phosphorus release by phosphorus-solubilizing fungi, it was found that strain L4 produces several organic acids, such as oxalic acid, lactic acid, acetic acid, succinic acid, tartaric acid, malic acid, and citric acid. At 24 h, the alkaline phosphatase and acid phosphatase activities reached 154.72 mol/(L·h) and 120.99 mol/(L·h), respectively.

Keywords: Mortierella; phosphate-solubilizing microorganisms; phosphorus-solubilizing capacity; phosphorus-solubilizing fungi.

Grants and funding

This research was funded by the Korea Environment Industry and Technology Institute (KEITI) through a project to develop new, ecofriendly materials and processing technology derived from wildlife, funded by the Korea Ministry of Environment (MOE), grant number 2021003240004; by the National Research Foundation of Korea (NRF), with a grant funded by the Korean government, grant number NRF-2018R1C1B3009513; by the Natural Science Foundation of China, grant number 31570107; by the Korea Research Institute of Bioscience and Biotechnology (KRIBB) Research Initiative Program, grant number KGM5252221; and by the National Key Research and Development Program of China, grant number 2021YFD02200403. This research was also supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).