Potential of Rhizobacteria for Promoting Sorghum Growth and Suppressing Striga hermonthica Development

Abstract

The objective of this study was to screen the potential of four plant growth promoting rhizobacteria (PGPR) for growth promotion in sorghum (Sorghum bicolor) and suppression of Striga hermonthica development. Bacillus subtilis Bsn5, B. subtilis GBO3, B. amyloliquefaciens FZB42 and Burkholderia phytofirmans PsJN were evaluated under controlled conditions in growth chambers. After 28 days of growth, the effect of selected PGPR on sorghum plant height, leaf chlorophyll (SPAD) value, biomass dry matter (DM), number of germinated and attached Striga plants and number of Striga plants that developed tubercles was analyzed. Inoculated Striga-free sorghum plants were significantly taller, with higher leaf chlorophyll SPAD values and higher dry matter than uninoculated Striga-free plants. However, there were no differences in sorghum height, SPAD value and DM between inoculated and uninoculated Striga-infected sorghum plants. In the absence of PGPR inoculation, differences in DM were observed between Striga-free and Strigainfected sorghum. Compared to the untreated control, Striga seed germination was lower in the sorghum plants treated with B. subtilis GBO3 and B. amyloliquefaciens FZB42. Of the germinated Striga seeds, the percentage that attached to the sorghum plant was lowest (23%) in the B. subtilis GBO3 treatment. The percentage of dead Striga tubercles in the PGPR treatments ranged between 35 and 59%, compared to 3% in the untreated control. This study identified B. subtilis GBO3, B. amyloliquefaciens FZB42 and Burkholderia phytofirmans PsJN with promising potential to promote sorghum growth and suppress Striga.

Rhizobacterial species richness improves sorghum growth and soil nutrient synergism in a nutrient-poor greenhouse soil

“…Previously, some studies have reported a positive effect of individual rhizobacterial species on plant density due to their positive effects on seed germination of sorghum and other plants 59 , 60 ; however, we did not find a significant positive effect of six different individual rhizobacterial species on this plant trait. While increasing the species diversity of rhizobacterial seed-inoculated probiotics substantially increased plant density (Fig.…”

Recent research progress in combatting root parasitic weeds

“…Aspergillus alliaceus isolated from O. cernua in sunflower fields very quickly caused necrosis and then greatly diminished the number of attachments, tubercles and emergent shoots as well as the total shoot number of O. crenata in laboratory, pot and field experiments [122]. Among the plant growth-promoting rhizobacteria tested by Mounde et al [123], Bacillus subtilis GBO3 and Burkholderia phytofirmans PsJN had considerable potential in both S. hermonthica suppression through preventing germination and growth promotion of sorghum. A culture filtrate of an actinomycete strain, Streptomyces enissocaesilis, significantly reduced the germination of O. cumana seeds in germination tests in Petri dish and rhizotron assays [124].…”

Inhibitory activity of bacterial lipopeptides against Fusarium oxysporum f.sp. Strigae

“…On the other hand, the result revealed that P. phytofirmans PsJN tended to have a positive effect on Fos development. P. phytofirmans PsJN is known for its potential plant growth promotion and disease resistance induction [ 29 , 58 ], and its ability to produce various compounds such as phytohormones, siderophores and other secondary metabolites [ 59 , 60 ]. In addition, the genome of P. phytofirmans PsJN contains a NRPS gene cluster responsible for the synthesis of LP [ 61 ].…”

“…strigae (Fos), which is a putative and effective mycoherbicide for controlling Striga [ 26 – 28 ], with plant-growth promoting Bacillus velezensis GB03. Despite the potential for enhanced Striga suppression [ 29 ], co-inoculation did not yield better results compared to individual inoculation, suggesting incompatibility between the co-inoculants [ 30 ]. The incompatibility between these two potent biocontrol agents may limit their potential to be jointly applied as a microbial assemblage for controlling Striga .…”