Jingyu Zhang ¹ Minghao Liu ² N'da brou jean Landry ¹ Yaping Duan ¹ Xin Li ¹ Xingang Zhou ^1*

• ¹ Northeast Agricultural University, Harbin, China
• ² Arizona State University, Tempe, Arizona, United States

Returning straw can alter the soil microbial community, reduce the occurrence of soil-borne diseases and promote plant growth. Here, we aimed to evaluate the effects of Ricinus straw on tomato growth and rhizosphere microbial community. We carried out the microcosm experiments to investigate effects of Ricinus straw with different dosages (0%, 1% and 3%) on tomato dry biomass and rhizosphere bacterial and fungal community. The results indicated that the dry biomass of tomato seedlings with 1% addition of Ricinus straw increased by 53.98%. In addition, Ricinus straw also changed the abundances, diversities, and composition of tomato rhizosphere microbial communities. In detail, 1% addition of Ricinus straw increased the relative abundance of putative beneficial bacteria and fungi in straw decomposition, such as Ramlibacter sp., Azohydromonas sp., Schizothecium sp., and Acaulium sp., and decreased the relative abundance Fusarium sp.. Meanwhile, Ricinus straw inhibited the growth of putative pathogenic microorganisms. The correlation analysis showed that the changes in fungal community OTUs stimulated by Ricinus straws addition, may play a crucial positive regulatory role in tomato growth. Finally, the representative fungal strains Fusarium oxysporum f. sp. Lycopersici (FOL), named TF25, was isolated and cultured.We found Ricinus straw extract inhibited the growth of TF25 in in vitro experiment with inhibition rate 34.95% -51.91%. Collectively, Ricinus straw promoted plant growth by changing the rhizosphere microbial community composition and inhibiting FOL growth, which provides new evidence for understanding the improvement of key microorganism composition in improving crop growth and the sustainability of agriculture.