The growth and yields of crops are severely threatened by drought stress. As the symbiotic partners of plants, however, the function of the symbiotic interactions between arbuscular mycorrhizal fungi (AM fungi) and endophytic fungi on host drought resistance still unclear. Recently, the team led by Prof. Chuan-Chao Dai from the College of Life Sciences, Nanjing Normal University has published their findings entitled “Endophytic fungus improves peanut drought resistance by reassembling root-dwelling community of arbuscular mycorrhizal fungi” in the Fungal Ecology (https://doi.org/10.1016/j.funeco.2020.100993). This study addressed this scientific question.
Through high-throughput sequencing towards the root-dwelling AM fungal community structure of peanut cultivated in a natural soil environment under different soil water condition, the researchers found that the inoculation of endophytic fungus Phomopsis liquidambaris B3 (B3) reassembled the root-dwelling AM fungal community by driving the colonization of Gigaspora. Along with the change of AM fungal community structure, the drought resistance of peanut under drought stress was also improved. Co-inoculation experiments under sterilized condition revealed that the synergetic interactions between B3 and AM fungi (Gigaspora margarita, G. margarita) promoted the secretion of glomalin from the extraradical hyphae of G. margarita. The higher content of glomalin in the bulk soil promoted the formation of soil aggregates and thus enhanced the peanut drought resistance. Although root exudates are widely considered to be the priming factor of the symbiotic recognition between AM fungi and plant host, both endophytic fungal exudates and root exudates failed to differentiated affect the pre-symbiotic growth (spore germination and hyphal development) of different AM fungi. The results of Pearson analysis showed that soil pH and root soluble sugar content were the two factors that had the greatest influence on the root-dwelling AM fungal community structure of peanut. Overall, this study enable us to better understand the ecological importance of the tripartite symbiosis between endophytic fungi, AM fungi and host.
Prof. Chuan-Chao Dai from Nanjing Normal University is the corresponding author. Fang-ji Xu from the College of Life Sciences are first author. This work was financially supported by the the National Natural Science Foundation of China (grant no. 31870478) and the project funded by the Priority Academic Program Development (PAPD) of the Jiangsu Higher Education Institutions of China.