Abstract
Previous studies with Paenibacillus lentimorbus B-30488” (hereafter referred as B-30488), a plant growth promoting rhizobacteria (PGPR) isolated from cow’s milk, revealed its capabilities to improve plant quality under normal and stress conditions. Present study investigates its potential as a biocontrol agent against an economically important virus, Cucumber mosaic virus (CMV), in Nicotiana tabacum cv. White Burley plants and delineates the physical, biophysical, biochemical and molecular perturbations due to the trilateral interactions of PGPR-host-CMV. Soil inoculation of B-30488 enhanced the plant vigor while significantly decreased the virulence and virus RNA accumulation by ~12 fold (91%) in systemic leaves of CMV infected tobacco plants as compared to the control ones. Histology of these leaves revealed the improved tissue’s health and least aging signs in B-30488 inoculated tobacco plants, with or without CMV infection, and showed lesser intercellular spaces between collenchyma cells, reduced amount of xyloglucans and pectins in connecting primary cells, and higher polyphenol accumulation in hypodermis layer extending to collenchyma cells. B-30488 inoculation has favorably maneuvered the essential biophysical (ion leakage and photosynthetic efficiency) and biochemical (sugar, proline, chlorophyll, malondialdehyde, acid phosphatase and alkaline phosphatase) attributes of tobacco plants to positively regulate and release the virus stress. Moreover, activities of defense related enzymes (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and catalase) induced due to CMV-infection were ameliorated with inoculation of B-30488, suggesting systemic induced resistance mediated protection against CMV in tobacco. The quantitative RT-PCR analyses of the genes related to normal plant development, stress and pathogenesis also corroborate well with the biochemical data and revealed the regulation (either up or down) of these genes in favor of plant to combat the CMV mediated stress. These improvements led tobacco plant to produce more flowers and seeds with no negative impact on plant health. The present study may advocate the applicability of B-30488 for crop yield improvement in virus infested areas.
Highlights
Plant growth-promoting rhizobacteria (PGPR), the advantageous colonized bacterial population associated with plant’s root, have been well documented for several beneficial attributes in crop plants
Infected plants were exhibiting the symptoms of severe mosaic on more than 50% surface area of systemic leaves accompanied with leaf deformation and stunting of plant (Fig 1a, Cucumber mosaic virus (CMV)) as compared to the healthy ones (Fig 1a, control ones (Control)) which has 0 scale disease rating
The applicability of B-30488, a PGPR that has already shown the potential of enhancing plant vigour [7] and ameliorating the biotic and abiotic stress [5,7], has been further assessed as a biological control agent (BCA) against virus (CMV) infection in N. tabacum cv
Summary
Plant growth-promoting rhizobacteria (PGPR), the advantageous colonized bacterial population associated with plant’s root, have been well documented for several beneficial attributes in crop plants. One of the earliest virtues associated with PGPR is the promotion of plant’s growth for high yield or biomass [1,2,3]. Another lucrative property of PGPR is to elicit the defense system in plants and to improve the plant’s ability to withstand abiotic stress conditions such as dry or cold weather, sodic or chemical amended soil etc. The implementation of PGPR as BCA is increasingly being accepted and has shown promising results in managing a wide spectrum of plant viruses in several crops or model plants under greenhouse as well as in field conditions [11,12,13,14,15,16,17,18]. Attempts have been made to delineate the affects of a PGPR in Nicotiana tabacum cultivar White Burley plants (a well known model and commercially important plant) using an economically important plant virus, Cucumber mosaic virus (CMV) [19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
