Background: Bacterial wilt caused by Ralstonia solanacearum is a devastating disease of brinjal in Bangladesh. The study was targeted to evaluate the bacterial wilt management ability of microbial consortia composed of isolated and identified native Bacillus cereus, Trichoderma harzianum and Calotropis gigantea for the first time in Bangladesh. Results: Twenty bacterial strains were isolated from the rhizosphere of the brinjal plant following serial dilution method. Among the strains, HSTUB 17 showed maximum zone of inhibition (1.5 ± 0.1 cm) against R. solanacearum in the dual culture method. Molecular characterization using 16 s rRNA partial coding sequence revealed HSTUB 17 as B. cereus. Consortia composed with the identified B. cereus HSTUB 17 (10⁸ CFU ml⁻¹ @ 5 ml/plant), previously isolated T. harzianum (@5 mm size of four mycelial disk/plant) and aqueous leaf extracts of C. gigantea (1:1, w/v basis @ 40 ml/plant) were applied in the root zone following soil drenching method and found to reduce bacterial wilt incidence by 74.87, 66.67 and 66.67% at 30, 50 and 70 days after transplanting, respectively, in comparison with plants received only R. solanacearum (10⁸ CFU ml⁻¹ @ 5 ml/plant). The single application of B. cereus HSTUB 17, T. harzianum and C. gigantea also minimized wilt incidence by 21.16–37.34, 33.33 and 21.48–28.14%, respectively, on all the days of observations. The consortia of B. cereus HSTUB 17, T. harzianum and C. gigantea also resulted in maximum plant height (56.67 cm), the number of branches/plants (10.33), the number of fruits/plants (8.33) and fruit yield (25.56 ton/ha) in comparison with the plant exposed to R. solanacearum only. Conclusion: The findings of the study revealed the potentiality of consortia composed of B. cereus HSTUB 17, T. harzianum and C. gigantea for the eco-friendly management of bacterial wilt of brinjal for the first time in Bangladesh.

Alkaloids are the most diversified nitrogen-containing secondary metabolites, having antioxidant and antimicrobial properties, and are extensively used in pharmaceuticals to treat different types of cancer. Nicotiana serves as a reservoir of anti-cancer alkaloids and is also used as a model plant for the de novo synthesis of various anti-cancer molecules through genetic engineering. Up to 4% of the total dry weight of Nicotiana was found to be composed of alkaloids, where nicotine, nornicotine, anatabine, and anabasine are reported as the dominant alkaloids. Additionally, among the alkaloids present in Nicotiana, β-carboline (Harmane and Norharmane) and Kynurenines are found to show anti-tumor effects, especially in the cases of colon and breast cancers. Creating new or shunting of existing biosynthesis pathways in different species of Nicotiana resulted in de novo or increased synthesis of different anti-tumor molecules or their derivatives or precursors including Taxadiane (~22.5 µg/g), Artemisinin (~120 μg/g), Parthenolide (~2.05 ng/g), Costunolide (~60 ng/g), Etoposide (~1 mg/g), Crocin (~400 µg/g), Catharanthine (~60 ng/g), Tabersonine (~10 ng/g), Strictosidine (~0.23 mg/g), etc. Enriching the precursor pool, especially Dimethylallyl Diphosphate (DMAPP), down-regulating other bi-product pathways, compartmentalization or metabolic shunting, or organelle-specific reconstitution of the precursor pool, might trigger the enhanced accumulation of the targeted anti-cancer alkaloid in Nicotiana.

Alkaloids are the most diversified nitrogen-containing secondary metabolites having antioxi-dant, and antimicrobial properties and are extensively used in pharmaceuticals to treat different types of cancer. Nicotiana serves as a reservoir of anticancer alkaloids and is also used as a model plant for the de novo synthesis of various anti-cancer molecules through genetic engineering. Up to 4% of the total dry weight of Nicotiana was found to be composed of alkaloids where nicotine, nornicotine, anatabine, and anabasine are reported as the dominant alkaloids. And, among the alkaloids present in Nicotiana, β-carboline (Harmane and Norharmane), Kynurenines are found to show anti-tumor effects, especially in the case of colon and breast cancer. Creating new or shunting of existing biosynthesis pathways in different species of Nicotiana resulted in de novo or increased synthesis of different anti-tumor molecules or their derivatives or precursors includ-ing Taxadiane (~22.5 µg/g), Artemisinin (~120 μg/g), Parthenolide (~2.05 ng/g), Costunolide (~60 ng/g), Etoposide (~1 mg/g), Crocin (~400 µg/g), Catharanthine (~60 ng/g), Tabersonine (~10 ng/g), Strictosidine (~0.23 mg/g), etc. Enrich precursor pool especially Dimethylallyl Diphos-phate (DMAPP) and down-regulating of other bi-product pathways, compartmentalization or metabolic shunting, or organelle-specific reconstitution of the precursor pool might trigger the enhanced accumulation of the targeted anticancer alkaloid in Nicotiana.