AUTHOR=Ajesh B. R. , Sariga R. , Nakkeeran S. , Renukadevi P. , Saranya N. , Alkahtani Saad 

TITLE=Insights on mining the pangenome of Sphingobacterium thalpophilum NMS02 S296 from the resistant banana cultivar Pisang lilin confirms the antifungal action against Fusarium oxysporum f. sp. cubense

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1443195

DOI=10.3389/fmicb.2024.1443195

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p><italic>Fusarium</italic> wilt, caused by <italic>Fusarium oxysporum</italic> f. sp. <italic>cubense</italic> (<italic>Foc</italic>), poses a significant global threat to banana cultivation. Conventional methods of disease management are increasingly challenged, thus making it necessary to explore alternative strategies. Bacterial endophytes, particularly from resistant genotypes, are gaining attention as potential biocontrol agents. <italic>Sphingobacterium thalpophilum</italic>, isolated from the resistant banana cultivar <italic>Pisang lilin</italic> (JALHSB010000001-JALHSB010000029), presents an intriguing prospect for combating <italic>Fusarium</italic> wilt. However, its underlying biocontrol mechanisms remain poorly understood. This study aimed to elucidate the antifungal efficacy of <italic>S. thalpophilum</italic> NMS02 S296 against <italic>Foc</italic> and explore its biocontrol mechanisms at the genomic level.</p></sec><sec><title>Methods</title><p>Whole genome sequencing of <italic>S. thalpophilum</italic> NMS02 S296 was conducted using next-generation sequencing technologies and bioinformatics analyses were performed to identify genes associated with antifungal properties. <italic>In vitro</italic> assays were used to assess the inhibitory effects of the bacterial isolate on the mycelial growth of <italic>Foc</italic>. To explore the biomolecules responsible for the observed antagonistic activity, metabolites diffused into the agar at the zone of inhibition between <italic>Foc</italic> S16 and <italic>S. thalpophilum</italic> NMS02 S296 were extracted and identified.</p></sec><sec><title>Results</title><p>Whole genome sequencing revealed an array of genes encoding antifungal enzymes and secondary metabolites in <italic>S. thalpophilum</italic> NMS02 S296. In vitro experiments demonstrated significant inhibition of <italic>Foc</italic> mycelial growth by the bacterial endophyte. Comparative genomic analysis highlighted unique genomic features in <italic>S. thalpophilum</italic> linked to its biocontrol potential, setting it apart from other bacterial species.</p></sec><sec><title>Discussion</title><p>The study underscores the remarkable antifungal efficacy of <italic>S. thalpophilum</italic> NMS02 S296 against <italic>Fusarium</italic> wilt. The genetic basis for its biocontrol potential was elucidated through whole genome sequencing, shedding light on the mechanisms behind its antifungal activity. This study advanced our understanding of bacterial endophytes as biocontrol agents and offers a promising avenue for plant growth promotion towards sustainable strategies to mitigate <italic>Fusarium</italic> wilt in banana cultivation.</p></sec>