Plant growth promoting rhizobacteria Dietzia natronolimnaea modulates the expression of stress responsive genes providing protection of wheat from salinity stress

Abstract

Plant growth promoting rhizobacteria (PGPR) hold promising future for sustainable agriculture. Here, we demonstrate a carotenoid producing halotolerant PGPR Dietzia natronolimnaea STR1 protecting wheat plants from salt stress by modulating the transcriptional machinery responsible for salinity tolerance in plants. The expression studies confirmed the involvement of ABA-signalling cascade, as TaABARE and TaOPR1 were upregulated in PGPR inoculated plants leading to induction of TaMYB and TaWRKY expression followed by stimulation of expression of a plethora of stress related genes. Enhanced expression of TaST, a salt stress-induced gene, associated with promoting salinity tolerance was observed in PGPR inoculated plants in comparison to uninoculated control plants. Expression of SOS pathway related genes (SOS1 and SOS4) was modulated in PGPR-applied wheat shoots and root systems. Tissue-specific responses of ion transporters TaNHX1, TaHAK, and TaHKT1, were observed in PGPR-inoculated plants. The enhanced gene expression of various antioxidant enzymes such as APX, MnSOD, CAT, POD, GPX and GR and higher proline content in PGPR-inoculated wheat plants contributed to increased tolerance to salinity stress. Overall, these results indicate that halotolerant PGPR-mediated salinity tolerance is a complex phenomenon that involves modulation of ABA-signalling, SOS pathway, ion transporters and antioxidant machinery.

Rhizosphere engineering: Enhancing sustainable plant ecosystem productivity

“…Also, inoculated tomato plants with certain PGPRs were shown to be able to maintain their growth under high-salinity and water-limited conditions by reducing the negative impact of stress-induced ethylene release on root growth through the activity of bacterial ACC-deaminase (Mayak et al, 2004). In a recent study, Bharti et al (2016) demonstrated the use of a carotenoid-producing halotolerant PGPR Dietzia natronolimnaea strain STR1 in conferring salinity tolerance in wheat.…”

“…Inoculated plants had higher expression of proline and various antioxidants, enabling these plants to withstand salinity stress (Bharti et al, 2016). Moreover, ABA signaling, SOS pathways and iron transport were activated in these plants as a result of PGPR inoculation.…”

Pseudomonas knackmussiiMLR6, a rhizospheric strain isolated from halophyte, enhances salt tolerance inArabidopsis thaliana

“…Recently, several studies demonstrated that the application of PGPR can significantly improve plant tolerance to salt stress (Egamberdieva and Lugtenberg ; Bharti et al . ; Habib et al . ; Sapre et al .…”

The Starter Effect of Non-Symbiotic Microbial Bioproducts on Wheat

“…1.). Shoot development is sensitive to absence and inoculum dose (Bashan, 1986, Bharti et al, 2016, Lindberg et al, 1985. At low dose inoculum (da) the root percentage and root/shoot ratio have the highest values, with insertion in PCA Axis 1.…”