The influence of Bacillus velezensis (GF-46) on the root system of corn
Bacillus belaisi strain GF-46 significantly promotes corn growth and enhances its resistance to stem rot through two mechanisms. In terms of promoting growth, Bacillus belaisi strain GF-46 significantly increases the content of auxin IAA in corn by activating the auxin synthesis pathway (upregulating the YUCCA gene and tryptophan), thereby promoting root development (root length, surface area, branch number) and above-ground biomass (fresh weight, dry weight, stem diameter, etc.), ultimately increasing yield (yield increase of 6.48%). At the same time, it can enrich SWEET family genes, optimize sugar transport capacity, and synergize with the IAA pathway to enhance carbon-nitrogen metabolism, supporting plant growth by promoting carbohydrate distribution. In terms of disease resistance, Bacillus belaisi strain GF-46 induces the jasmonic acid JA signaling pathway (LOX gene expression) to stimulate the self-system resistance (ISR) of corn, and strengthens the physical defense of corn stems and roots (genes related to lignin and cellulose synthesis such as UGPase, CesA, etc.), enhances antioxidant enzymes (SOD, POD, CAT) activity, thereby reducing the incidence of stem rot caused by Fusarium graminearum (efficiency of 70.13%).