Biological control serves as a crucial strategy for crop disease management. The biocontrol potential and plant growth-promoting effects of the strain YTBTa14 were investigated. Genetic sequencing confirmed YTBTa14 as Pseudomonas chlororaphis, which exhibited broad-spectrum antifungal activity against multiple pathogens affecting grapevine, apple, cherry, and wheat. YTBTa14 significantly enhanced the growth of wheat and grapevine, specifically increasing wheat seed germination rates and improving root and coleoptile development. In grapevine plant, significant increases in root length, stem length, and fresh weight were observed. The strain demonstrated robust adaptability and stable antagonism under varying sodium chloride (NaCl) concentrations, pH levels, and temperatures. YTBTa14 modulated plant hormone levels, elevating the content of indole-3-acetic acid (IAA), gibberellins (GA), and cytokinins (CTK). Furthermore, it effectively stimulated the production of key plant defense enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT). Pretreatment of grape leaves with YTBTa14 triggered plant cell defense response and upregulated the expression of defense-related genes PR1 (pathogenesis-related protein 1) and PAL1 (phenylalanine ammonia-lyase 1), thereby mitigating the severity of downy mildew disease and inducing systemic resistance. These findings demonstrate that YTBTa14 is a highly promising candidate for development as a multifunctional agricultural biocontrol agent.

To clarify the effects of newly developed controlled-release iodine fertilizer (CRIF) on enhancing lettuce (Lactuca sativa L.) iodine accumulation, improving the physiological traits, and reducing iodine leaching from soil, a greenhouse pot experiment was conducted. Polymer-coated iodate (PCIO), polymer-coated iodide (PCI), and two conventional iodine fertilizers—iodate (CIO) and iodide (CI)—were applied at a rate of 15 mg iodine per kg soil. The study found that the coating of iodine fertilizers had no significant effects on the biomass of lettuce. The iodine concentration in lettuce leaves subjected to PCIO treatment was elevated by 50.1% and 45.5%, respectively, in comparison to leaves treated with CIO and PCI. The soil-to-leaf transfer factor (TF_leaf, dry weight basis) for plants treated with PCIO was significantly higher than that of PCI-treated plants. PCIO also significantly reduced iodine leaching by 46.3% compared to CIO. In lettuce leaves with PCIO treatment, the enzymatic activities of superoxide dismutase (SOD) and catalase (CAT) significantly increased by 50.8% and 27.6%, respectively. Likewise, malo-naldehyde (MDA) levels decreased by 23.2% compared to the control samples. PCIO also demonstrated advantages in enhancing the quality of the lettuce. In conclusion, the application of controlled-release iodine fertilizer could be a highly effective and eco-friendly approach to cultivating iodine-rich vegetables.

The purpose of this study is to discover and excavate more key factors and signaling pathways that regulate the formation intensity of biofilms and to fully reveal the possible models affecting biofilm formation. By using gene homologous recombination and bioinformatics technology, a MutL protein-directed deletion mutant strain was successfully constructed. The growth status of the mutant strain was observed, and it was confirmed that, except for the change in cell morphology, there were no significant differences in growth and reproduction between the mutant strain and the wild-type strain. By using the induced biofilm formation technique, the significant decrease in biofilm formation in the MutL mutant strain was successfully verified. The plate confrontation test confirmed that the inhibitory ability of the mutant strain against rice blast fungus was not significantly different from that of the WT strain. The colonization ability of the mutant strain on rice stems was tested, and it was confirmed that the colonization ability of the mutant strain was significantly lower than that of the WT strain. In terms of the prevention and control effect of rice blast disease, the mutant strain showed a significant decrease. By using transcriptomic big data, the gene and pathway expression differences between the mutant strain and the WT strain during biofilm formation were analyzed. The analysis revealed no significant correlation with the previously reported spo0A and tapA-sipW-tasA pathways. The key factor capB of the polyglutamic acid signaling pathway, which affects the formation of the biological model, was found to have a significant decrease in expression. A mechanical hypothesis was proposed: MutL may participate in regulating the formation intensity of Bacillus biofilms by regulating the formation of glutamic acid to polyglutamic acid.