Interactions between a plant growth‐promoting rhizobacterium and smoke‐derived compounds and their effect on okra growth

Abstract

Plant growth‐promoting rhizobacteria (PGPR) are used in agriculture to improve crop yield. Crude smoke–water (made by bubbling plant‐derived smoke through water) stimulates germination and improves seedling growth. Some active compounds have been isolated from smoke with karrikinolide (KAR1) stimulating plant growth and trimethylbutenolide (TMB) being inhibitory. These smoke compounds have great potential in agriculture but their interaction with PGPR is unknown. In the present study, a two‐factorial pot trial with three replicates per treatment was designed to investigate the interactions between Bacillus licheniformis and two concentrations each of smoke–water, KAR1, and TMB on okra (Abelmoschus esculentus). Growth and physiological parameters (chlorophyll, carotenoid, protein, sugar and α‐amylase) of okra as well as bacterial abundance in the rhizosphere were measured after 5 weeks. Application of B. licheniformis and 10−7 M KAR1 significantly improved the shoot biomass and 10−7 M KAR1 also significantly improved leaf area of okra. However, when 10−7 M KAR1 was applied in combination with B. licheniformis, there was an antagonistic effect on plant growth. While TMB had a negative effect on plant growth, a combination treatment of TMB and B. licheniformis overcame the inhibitory effect of TMB resulting in plant growth similar to the control plants. All treatments had no effect on chlorophyll, carotenoid, protein and sugar concentrations, while α‐amylase activity was significantly elevated in okra root treated with 1:500 (v/v) smoke–water. Determining the rhizobacteria populations at harvest showed that all treatments had no significant effect on the rhizosphere microbial abundance. The modes of interaction between PGPR and smoke‐derived compounds need to be further elucidated.

Role of Smoke Stimulatory and Inhibitory Biomolecules in Phytochrome-Regulated Seed Germination of Lactuca sativa

“…SW enhanced soluble sugar and proteins related to signaling and transport (Rehman et al, 2018). a-Amylase activity was slightly elevated in okra (Abelmoschus esculentus) roots with SW and KAR 1 (Papenfus et al, 2015). SW and KAR 1 also stimulate growth in bean and maize (Zea mays) seedlings by efficient starch mobilization (Sunmonu et al, 2016).…”

Effects of Smoke Water on Seeds Germination, Seedling Growth of some Vegetables and Green Yield Productivity of Phaseolus vulgaris

“…Concerning the negative influence of smoke water on tomato, onion and celery, it may be returned to fact that the presented of some compounds which had been isolated from smoke water and called tri-methyl-butenolide (TMB) which act as an inhibitory impact on seedlings growth as confirmed by (Papenfus et al, 2015).…”

Effect of auxins on the native proteolytic activity of forest soils

“…Syntheses of phytohormones, auxins and cytokinins in particular, make a symbiotic association between a plant and a microbial soil coenosis ( Tsavkelova et al, ). Being concerned with auxins and plants, they affect vegetative growth, flowering, the photosynthetic assimilation of carbon dioxide, and resilience against environmental stress ( Papenfus et al, ). However, not only plants are capable of producing phytohormones, but rhizospheral microorganisms can also do the same ( Ali et al, ).…”