Diversity of endophytic fungi in the roots of traditional Chinese medicines under rubber forests and their correlation with the physicochemical properties of rhizosphere soil

【Objective】 To analyze the diversity of endophytic fungi in the roots of traditional Chinese medicines under rubber plantations and their correlation with the physicochemical properties of the rhizosphere soil，which could provide theoretical basis for the cultivation of traditional Chinese medicines and the development and utilization of endophytic fungal resources in the roots. 【Method】 Baphicacanthus cusia，Amomum villosum，Alpinia oxyphylla and Alpinia officinarum root and rhizosphere soil samples of 4 traditional Chinese medicines were all collected from the demonstration base in Puwen Town，Jinghong City，Xishuangbanna Dai Autonomous Prefecture，Yunnan Province. The ITS sequences of endophytic fungi in the roots were sequenced to analyze the diversity of endophytic fungal communities in the roots. Linear discriminant analysis effect size（LEfSe）was used to screen the species with significant differences among the endophytic fungal communities in the roots of 4 traditional Chinese medicines. The physicochemical properties of the rhizosphere soil were determined and its correlation with the endophytic fungal community of the root was analyzed. 【Result】 The pH of the rhizosphere soil of Baphicacanthus cusia was significantly lower than that of Alpinia officinarum（P<0.05，the same below），and the content of available phosphorus was significantly higher than that of Amomum villosum，Alpinia oxyphylla and Alpinia officinarum. The total potassium content in the rhizosphere soil of Baphicacanthus cusia，Amomum villosum and Alpinia officinarum was significantly higher than that of Alpinia oxyphylla. The Chao1 index of the endophytic fungal communities in the roots of Baphicacanthus cusia，Amomum villosum and Alpinia officinarum was significantly higher than that of Alpinia oxyphylla，indicating that the abundance of the endophytic fungal communities in the roots of Baphicacanthus cusia，Amomum villosum and Alpinia officinarum was significantly higher than that of Alpinia oxyphylla. A total of 8 phyla were detected in the endophytic fungal communities of the roots of 4 traditional Chinese medicines. The dominant phyla of Baphicacanthus cusia，Amomum villosum and Alpinia officinarum were Ascomycota and Basidiomycota，while the dominant phylum of Alpinia oxyphylla was Ascomycota. Through LEfSe analysis，it was found that the endophytic fungal communities in the roots of 4 traditional Chinese medicines all had biomarkers that could distinguish them from each other. The correlation analysis results showed that in the endophytic fungal community of Amomum villosum， the Glomeromycota phylum was significantly and positively correlated with the organic matter content in the rhizosphere soil. In the endophytic fungal community of the roots of Alpinia oxyphylla，Glomeromycota was extremely significantly and negatively correlated with the total potassium conten（t P<0.01）. The Chao1 index of the endophytic fungal community in the roots of Amomum villosum was significantly and positively correlated with the pH of the rhizosphere soil. The Shannon index of the endophytic fungal community in the roots of Alpinia officinarum was significantly and negatively correlated with pH of the rhizosphere soil，while the Shannon index of the endophytic fungal community in the roots of the other 3 Chinese herbal medicines had no significant correlation with the physicochemical properties of the rhizosphere soil （P>0.05）. 【Conclusion】 All 4 traditional Chinese medicines have abundant endophytic fungal resources in their roots. The diversity of endophytic fungi in the roots of Baphicacanthus cusia，Amomum villosum and Alpinia oxyphylla has no significant correlation with the physicochemical properties of the rhizosphere soil. In contrast，the diversity of endophytic fungal communities in the roots of Alpinia officinarum responds more strongly to the pH changes of the rhizosphere soil.