The use of endophytic bacteria in agriculture provides an effective way of improving crop yield and significantly reducing chemical usage, such as fungicides. This research was conducted to explore endophytic bacteria with plant growth promotion (PGP) and antifungal activities against Fusarium moniliforme AIT01. In this study, we obtained 52 isolates of endophytic bacteria associated with the roots and stems of sugarcane from Nakhon Ratchasima province, Thailand. In vitro antagonistic activity test showed that 14 out of 52 isolates had antagonistic activity against the fungal pathogen F. moniliforme AIT01. These antagonistic endophytic bacteria were identified as belonging to six different species as follows: Nguyenibacter vanlangensis, Acidomonas methanolica, Asaia bogorensis, Tanticharoenia aidae, Burkholderia gladioli and Bacillus altitudinis based on phenotypic characteristics, along with phylogenetic analysis of their 16S rRNA gene sequences. Seven isolates effectively inhibited F. moniliforme AIT01 mycelial growth by up to 40%. The volatile compounds of six isolates reduced the growth of F. moniliforme AIT01 by over 23%. Moreover, riceberry rice seedlings previously treated with B. gladioli CP28 were found to strongly reduce infection with phytopathogen by 80% in comparison to the non-treated control. Furthermore, the isolates also showed relevant PGP features, including ammonia production, zinc and phosphate solubilisation, auxin and siderophore biosynthesis. These results demonstrated that the tested endophytic bacteria could be successfully utilised as a source of PGP and biocontrol agent to manage diseases caused by F. moniliforme.
Indole-3-acetic acid (IAA) is one of the most physiologically active auxins produced by rhizobacteria and is potentially applied for agriculture. Two endophytic bacteria, VR2 and MG9, isolated from the root of Chrysopogon zizanioides (L.) collected at Cha-Am, and the leaf of Bruguiera cylindrica (L.) Blume collected from a mangrove forest at Ban Laem, Phetchaburi Province, Thailand, were taxonomic characterised based on their phenotypic characteristics and 16S rRNA gene analysis. Strain VR2 was closely related to Enterobacter hormaechei CIP 103441T (99.6% similarity), while strain MG9 was closely related to Bacillus aryabhattai B8W22T (99.9% similarity). Consequently, they were identified as Enterobacter hormaechei and Bacillus aryabhattai, respectively. The IAA production of VR2 and MG9 strains are determined and applied to rice seeds for their root and shoot germination. Strains VR2 and MG9 greatly produced a yield of IAA, 246.00 and 195.55 μg/mL in 1,000 μg/mL of L-tryptophan at pH 6 for 48 h. They showed no significant differences in IAA to root and shoot development. However, the bacterial IAA exhibited potential nearby synthetic IAA, which had a significant effect compared to the control. IAA produced from these two strains might preferably trim down the use of synthetic IAA and could contribute to sustainable agriculture.
Lactiplantibacillus plantarum is a widely studied species known for its probiotic properties that can help alleviate serum cholesterol levels. Whole-genome sequencing provides genetic information on probiotic attributes, metabolic activities and safety assessment. This study investigates the probiotic properties of strain CRM56-2, isolated from Thai fermented tea leaves, using Whole-Genome Sequencing (WGS) to evaluate the safety, health-promoting genes and functional analysis. Strain CRM56-2 showed bile salt hydrolase (BSH) activity, assimilated cholesterol at a rate of 75.94%, tolerated acidic and bile environments and attached to Caco-2 cells. Based on ANIb (98.9%), ANIm (99.2%), and digital DNA-DNA hybridisation (98.3%), strain CRM56-2 was identified as L. plantarum. In silico analysis revealed that it was not pathogenic and contained no antibiotic-resistance genes or plasmids. L. plantarum CRM56-2 possessed genes linked to several probiotic properties and beneficial impacts. The genome of strain CRM56-2 suggested that L. plantarum CRM56-2 is non-hazardous, with potential probiotic characteristics and beneficial impacts, which could enhance its probiotic application. Consequently, L. plantarum CRM56-2 demonstrated excellent cholesterol-lowering activity and probiotic properties.