title: Enhanced nodulation of peanut when co-inoculated with fungal endophyte Phomopsis liquidambari and bradyrhizobium.
abstract: In peanut continuous cropping soil, the application of fungal endophyte Phomopsis liquidambari B3 showed peanut pod yield promotion and root nodule number increase. P. liquidambari improved soil environment by degrading allelochemicals and thus promoted peanut pod yield. Furthermore, peanut yield promotion is in part due to the root nodule increase since nodular nitrogen fixation provides the largest source of nitrogen for peanut. However, it is unknown whether this nodule number increase is induced by fungal endophyte. We therefore conducted several pot experiments using vermiculite to investigate the effects of P. liquidambari on peanut-bradyrhizobium nodulation. Our results showed that P. liquidambari co-inoculated with bradyrhizobium increased root nodule number and shoot accumulated nitrogen by 28.25% and 29.71%, respectively. Nodulation dynamics analysis showed that P. liquidambari accelerated nodule initiation and subsequent nodule development. Meanwhile, P. liquidambari was able to colonize the peanut root as an endophyte. The dynamics of P. liquidambari and bradyrhizobial root colonization analysis showed that P. liquidambari inoculation significantly increased the rate of bradyrhizobial colonization. Furthermore, P. liquidambari inoculation significantly increased flavonoids synthesis-related enzymes activities, two common types of flavonoid (luteolin and quercetin-peanut rhizobial nod gene inducer) secretion and lateral root (peanut rhizobial infection site) formation, indicating that P. liquidambari altered the peanut nodulation-related physiological and metabolic activities. These obtained results confirmed the direct contribution of P. liquidambari in enhancing peanut-bradyrhizobium interaction, nodulation and yield.
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Jiangsu Province, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Jiangsu Province, China.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Wang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Jiangsu Province, China; Jiangxi Key Laboratory of Ecological Research of Red Soil, Experimental Station of Red Soil, Chinese Academy of Sciences, Jiangxi Province, China.
authors.forename: Xing-Xiang
authors.initials: XX
authors.lastname: Wang
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Jiangsu Province, China.
authors.forename: Xing-Guang
authors.initials: XG
authors.lastname: Xie
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Jiangsu Province, China.
authors.forename: Md Ashaduzzaman
authors.initials: MA
authors.lastname: Siddikee
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Jiangsu Province, China.
authors.forename: Ri-Sheng
authors.initials: RS
authors.lastname: Xu
authors.affiliation: Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Sciences, Nanjing Normal University, Jiangsu Province, China. Electronic address: daichuanchao@njnu.edu.
authors.forename: Chuan-Chao
authors.initials: CC
authors.lastname: Dai
mesh_terms: D010367:Arachis / Q000254:growth & development* / Q000382:microbiology; D001203:Ascomycota / Q000502:physiology*; D020369:Bradyrhizobium / Q000502:physiology*; D060026:Endophytes; D005419:Flavonoids / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D009586:Nitrogen Fixation; D055170:Plant Root Nodulation; D018517:Plant Roots / Q000254:growth & development / Q000382:microbiology; D012988:Soil Microbiology; D013559:Symbiosis
chemical_list: D005419:Flavonoids; D009584:Nitrogen
keywords: Bradyrhizobium; Co-inoculation; Flavonoids; Fungal endophyte; Lateral root; Peanut