Paenibacillus mucilaginosus has widely been reported as a plant growth-promoting rhizobacteria (PGPR). However, the important genomic insights into plant growth promotion in this species remain undescribed. In this study, the genome of P. mucilaginosus G78 was sequenced using Illumina NovaSeq PE150. It contains 8,576,872 bp with a GC content of 58.5%, and was taxonomically characterized. Additionally, a total of 7337 genes with 143 tRNAs, 41 rRNAs, and 5 ncRNAs were identified. This strain can prohibit the growth of the plant pathogen, but also has the capability to form biofilm, solubilize phosphate, and produce IAA. Twenty-six gene clusters encoding secondary metabolites were identified, and the genotypic characterization indirectly proved its resistant ability to ampicillin, bacitracin, polymyxin and chloramphenicol. The putative exopolysaccharide biosynthesis and biofilm formation gene clusters were explored. According to the genetic features, the potential monosaccharides of its exopolysaccharides for P. mucilaginosus G78 may include glucose, mannose, galactose, fucose, that can probably be acetylated and pyruvated. Conservation of the pelADEFG compared with other 40 Paenibacillus species suggests that Pel may be specific biofilm matrix component in P. mucilaginosus. Several genes relevant to plant growth-promoting traits, i.e., IAA production and phosphate solubilization are well conserved compared with other 40 other Paenibacillus strains. The current study can benefit for understanding the plant growth-promoting traits of P. mucilaginosus as well as its potential application in agriculture as PGPR.

Bacillus velezensis is well known as a plant growth-promoting rhizobacteria (PGPR) and biocontrol agent. Nevertheless, there are very few reports on the study of B. velezensis on tomato early blight, especially the biocontrol effects among different inoculation concentrations. In this study, an IAA-producing strain, Bacillus velezensis YXDHD1-7 was isolated from the tomato rhizosphere soil, which had the strongest inhibitory effect against Alternaria solani. Inoculation with bacterial suspensions of this strain promoted the growth of tomato seedlings effectively. Furthermore, inoculations at 10⁶, 10⁷, and 10⁸ cfu/mL resulted in control efficacies of 100%, 83.15%, and 69.90%, respectively. Genome sequencing showed that it possesses 22 gene clusters associated with the synthesis of antimicrobial metabolites and genes that are involved in the production of IAA. Furthermore, it may be able to produce spermidine and volatile compounds that also enhance plant growth and defense responses. Our results suggest that strain YXDHD1-7 prevents early blight disease by promoting growth and enhancing the defense enzyme activities in tomato plants. This strain is a promising candidate for an excellent microbial inoculant that can be used to enhance tomato production.

Nitrogen loss during manure composting reduces the fertilizer value of the final product and increases its environmental burden. This study evaluated whether semi-permeable membrane covering could reduce gaseous emissions and promote mineral-N retention during the co-composting of swine manure and spent mushroom substrate. Conventional aerobic composting (AC) and semi-permeable membrane-covered aerobic composting (MCAC) were conducted for 35 d. Compared with AC, MCAC reduced the estimated cumulative emissions of NH₃, N₂O, and CH₄ by 53.1%, 34.1%, and 45.7%, respectively, and lowered the estimated direct global warming potential of direct CH₄ and N₂O emissions by 37.5%. On day 35, MCAC had higher NH₄⁺-N (530.5 vs. 172.0 mg kg⁻¹) and NO₃⁻-N concentrations (80.1 vs. 42.6 mg kg⁻¹) than AC. Total nitrogen concentration decreased by 14.98% in MCAC and 17.82% in AC from day 1 to day 35. Composting stage explained 33.95% of bacterial community variation, versus 5.71% for membrane covering. Metagenomic nitrogen-cycling profiles varied mainly over time, with higher ammonia-oxidation potential in MCAC on day 10. Profiles covaried mainly with moisture and inorganic nitrogen. Overall, semi-permeable membrane covering maintained thermophilic composting while reducing gaseous emissions. The lower NH₃ and N₂O emissions, together with the higher final NH₄⁺-N and NO₃⁻-N concentrations, indicate reduced gaseous N release and greater mineral-N retention under MCAC.