The effects of pre-harvest application of Bacillus velezensis LYB73 on rhizosphere soil properties, microbial communities, fruit quality, and flavor-related traits in different peach cultivars are still not well understood. In this study, three peach cultivars, “Jinxia” (JX), “Wanhujing” (WHJ), and “Youpantao” (YPT), were subjected to B. velezensis LYB73 treatment or a sterile-water control under field conditions. Rhizosphere bacterial (16S rRNA) and fungal (ITS) communities were analyzed by high-throughput sequencing. Soil physicochemical properties, fruit nutritional and functional components, antioxidant capacity, and electronic sensory traits were also evaluated. The application of LYB73 was associated with lower rhizosphere soil pH (5.52–6.82) and changes in several soil nutrient-related parameters. Microbial community analyses indicated that LYB73 treatment was accompanied by shifts in the composition of rhizosphere bacterial and fungal communities. For example, the relative abundance of Pseudomonadota increased in the JX treatment group, while Ascomycota was enriched in the JX and YPT treatment groups. At the genus level, taxa such as Gemmatimonas, Saitozyma, and Cephalotrichum showed increased relative abundance in some treated groups. Compared with the control, LYB73-treated fruits generally showed higher levels of reducing sugars, titratable acids, amino acids, total phenols, total flavonoids, and antioxidant capacity. The magnitude of these responses varied among cultivars: JX showed larger increases in total phenols, total flavonoids, and DPPH scavenging activity, WHJ showed a greater increase in amino acids and ABTS scavenging activity, and YPT showed the largest increase in superoxide anion scavenging activity. Electronic sensory analysis further suggested that LYB73 treatment affected taste and aroma-related traits, although the responses differed among cultivars. Correlation analysis showed that several dominant microbial genera were significantly associated with soil properties, fruit quality indices, and sensory indicators. Overall, these results suggest that pre-harvest application of B. velezensis LYB73 may influence rhizosphere microecology and fruit quality in a cultivar-dependent manner, providing preliminary support for its potential use in peach production.
Yang et al. (Sat,) studied this question.