Ralstonia solanacearum is a harmful pathogen that causes severe wilt disease in several vegetables. In the present study, we identified R. solanacearum from wilt of papaya by 16S rRNA PCR amplification. Virulence ability of R. solanacearum was determined by amplification of approximately 1500 bp clear band of hrpB gene. Further, in-vitro seed germination assay showed that R. solanacearum reduced the germination rate up to 26.21%, 34% and 33.63% of cucumber, bottle guard and pumpkin seeds, respectively whereas shoot and root growth were also significantly decreased. Moreover, growth inhibition of R. solanacearum was recorded using antibacterial compound from medicinal plant and antagonistic B. subtilis. Petroleum ether root extract of Rauvolfia serpentina showed highest 22 ± 0.04 mm diameter of zone of inhibition where methanolic extract of Cymbopogon citratus and ethanolic extract of Lantana camara exhibited 20 ± 0.06 mm and 20 ± 0.01 mm zone of inhibition against R. solanacearum, respectively. In addition, bioactive compounds of B. subtilis inhibited R. solanacearum growth by generating 17 ± 0.09 mm zone of inhibition. To unveil the inhibition mechanism, we adopted chemical-protein interaction network and molecular docking approaches where we found that, rutin from C. citratus interacts with citrate (Si)-synthase and dihydrolipoyl dehydrogenase of R. solanacearum with binding affinity of −9.7 kcal/mol and −9.5 kcal/mol while quercetin from B. subtillis interacts with the essential protein F0F1 ATP synthase subunit alpha of the R. solancearum with binding affinity of −6.9 kcal/mol and inhibit the growth of R. solanacearum. Our study will give shed light on the development of eco-friendly biological control of wilt disease of papaya.

Arabidopsis thaliana contains a family of nine genes known as plant intracellular Ras-group related leucine-rich repeat (LRR) proteins (PIRLs). These are structurally similar to animals and fungal LRR proteins and play important roles in developmental pathways. However, to date, no detailed tissue-specific expression analysis of these PIRLs has been performed. Therefore, in this study, we generated promoter:GUS transgenic plants for the nine A. thaliana PIRL genes and identified their expression patterns in seedlings and floral organs at different developmental stages. Most PIRL members showed expression in the root apical region and in the vascular tissue of primary and lateral roots. Shoot apex-specific expression was recorded for PIRL1 and PIRL8. Furthermore, PIRL1, PIRL3, PIRL5, PIRL6, and PIRL7 showed distinct expression patterns in flowers, especially in pollen and anthers. In addition, co-expression network analysis identified cases where PIRLs were co-expressed with other genes known to have specific functions related to growth and development. Taken together, the tissue-specific expression patterns of PIRL genes improve our understanding of the functions of this gene family in plant growth and development.

Lead (Pb) toxicity is one of the largest environmental crises in Bangladesh, significantly impairing plant growth and productivity. Therefore, eco-friendly and cost-effective Pb-toxicity mitigation strategies are highly desirable. The study aimed to explore the potential of Bacillus subtilis in mitigating Pb-toxicity along with plant improvement in Brassica alba L. In this study, Pb-toxicity significantly inhibited physiological and biochemical traits in B. alba, while the supplantation of B. alba significantly reverted these key physiological and growth attributes. The application of B. subtilis increased plant height by about 26%, shoot biomass by about 18%, root length by about 69%, chlorophyll a by 28.3%, chlorophyll b by 72.2%, total chlorophyll to near-control levels, carotenoids to control-comparable values, and total soluble protein by about 44%.These findings suggest that B. alba is able to actively respond to Pb-stress and that plays a significant role in enhancing plant growth and Pb-tolerance. This study further indicates that B. subtilis could be a sustainable frontier for ameliorating metal toxicity in crops. These findings together open a paradigm of eco-friendly and cost-effective strategies toward sustainable crop production and global food security.