Jinhui Jiang ¹ Guangxiong Fan ^1* Rong Wen ^1* Liu Tao ^1* Shuran HE ^2* Shengchao Yang ^3* Shuhui Zi ^1*

• ¹ Yunnan Agricultural University, Kunming, China
• ² 云南农业大学, Kunming, China
• ³ 红河学院, Honghe, China

The biological activities of osthole have been widely reported in recent years. However, few studies have been conducted on osthole in agriculture, and its effects on plant growth have little been reported. Therefore, in the present study, the effects of osthole and Bacillus amyloliquefaciens on the growth parameters, photosynthesis, antioxidant enzyme activities, disease incidence, and microbiome of forested western ginseng were tested. It fills the gap of the effects of osthole on plants, and also provides important theoretical support for the application of osthole in agriculture.Results showed that the use of osthole and B. amyloliquefaciens significantly improved the growth of Panax quinquefolius in a forest compared to that in the control treatment, increased the total chlorophyll and carotenoid content of P. quinquefolius, significantly increased its net photosynthetic rate, and decreased the stomatal conductance and intercellular CO2 levels. In addition, the use of osthole and B. amyloliquefaciens significantly improved ascorbate peroxidase and peroxidase (POD) activities, enhanced antioxidant activities of the P. quinquefolius POD, and reduced the disease incidence and index of ginseng anthracnose. Based on the ginseng microbiome analysis, the use of osthole and B. amyloliquefaciens could change the structure of the ginseng microbial community, significantly increase the diversity of ginseng bacteria, significantly decrease the diversity of ginseng fungi, stimulate the recruitment of more growth-promoting microorganisms to ginseng, and build a more stable microbial network in ginseng. We found that the application of osthole had a positive effect on the growth of American ginseng, providing a theoretical basis for its subsequent application in agriculture.