Comparative analysis of different bio-organic fertilizers on growth and rhizosphere environment of grapevine seedlings

Grapevine seedlings need to absorb a lot of nutrients from the soil during the growth process, and appropriate fertilizer can greatly promote the growth of seedlings. The purpose of this study was to investigate the effects of different bio-organic fertilizers (BOF) on shoot and root growth, soil biochemical characteristics, and bacterial communities of 'Shine Muscat' and 'Kyoho' seedlings. Four treatments were established: no fertilizer (CK), chemical fertilizer + organic fertilizer (T1), chemical fertilizer + bio-organic fertilizer 1 (T2, containing Bacillus amyloliquefaciens), chemical fertilizer + bio-organic fertilizer 2 (T3, containing Trichoderma). The results showed that BOF had better effects on growth and rhizosphere environment of grapevine seedling than organic fertilizer (OF) treated group. The shoot growth, chlorophyll content, and root growth with BOF of grapevine seedlings were generally better than those treated with OF. Compared with T1, T2 and T3 made grapevine seedlings meet the fixed drying requirement (main shoot 0.8 m) 1-4 weeks earlier. The expansion of roots and the improvement of root activity under BOF treatment were also beneficial to plant growth. Moreover, transcriptome analysis showed that BOF enhanced the phytohormones and cell wall processes in grapevine root, and up-regulated the expression of cell wall-related genes such as XTH23, EXPs, PME17, and auxin related genes such as ABCBs and GH3. In addition, BOF increased soil organic matter content, available nitrogen, available potassium, available phosphorus, and enzyme activity (soil catalase, urease, sucrase, and nitrate reductase). The Shannon and Chao values of T2 were higher than those of T1 and CK, which improved the diversity and richness of soil microbial community. As compared to CK, T2 treatment increased the symbiotic nitrogen fixing Proteobacteria by 4.10 %, and reduced Acidobacteria by 9.79 %. Actinobacteria, which is related to the degradation of stubborn polymers, was the dominant group in T2 treatment, accounting for 10.17 %. As compared to CK and T1, Actinobacteria was increased by 6.89 % and 5.66 %. In summary, BOF could promote the growth of grapevine seedlings by improving phenotypic traits, soil fertility, bacterial diversity, richness abundance, and provide theoretical and technical support for grapevine garden construction and tree management.