Genomic analysis of Bacillus subtilis sub sp. subtilis GEB5 reveals its genetic assets for nematicidal and plant growth promoting mechanisms

Abstract

The immense benefit of chemical nematicides in controlling plant parasitic nematodes in high-value crops is counterbalanced by the development of resistance in nematodes due to their overuse. Bacillus subtilis is a promising bacterium that not only confers resistance against plant parasitic nematodes but also promotes plant growth through nutrient acquisition. Considering the multifaceted action of B. subtilis attempts were made to sequence the whole genome of endophytic B. subtilis GEB5 to find the genome complexity of the potential bio-control agent isolated from the guava. The results confirmed the isolate as B. subtilis sub sp. subtilis with a circular genome of 8,341,276 bp (8.3 Mb) length and 41.8% GC content. The results of genome annotation revealed the presence of 8209 coding sequences (CDS) genes, 136 transfer RNA (tRNA) genes, and 6 ribosomal RNA (rRNA) genes. Nonribosomal peptide synthetase (NRPS) gene clusters in the genome of GEB5 included fengycin, bacillaene, plipastatin, subtilin, subtilosin A, bacilysin, surfactin, sporulation killing factor, bacillibactin. Moreover, the GEB5 genome assembly had 21 homologs corresponding to nematode-virulent proteases. Furthermore, the results of greenhouse experiments showcased that GEB5 quenched the population of M. enterolobii (72% reduction) and also boosted the plant growth of guava. A plurality of the putatively encoded nematode virulence protease and its ability to boost plant growth suggests its environmentally robust bio-control potential in protecting plants against invading plant parasitic nematodes.