Abstract
Salt-tolerant plant growth-promoting rhizobacteria (PGPR) could be an alternative to alleviate salinity problems in rice plants grown in the coastal areas. This study was conducted to isolate and characterize salt-tolerant PGPR and observe their effects on the physiological and biochemical properties of rice plants grown under non-saline and saline glasshouse conditions. Three strains were selected based on their salt-tolerance and plant growth-promoting properties under in vitro saline conditions. These strains were identified as Bacillus tequilensis (UPMRB9), Bacillus aryabhattai (UPMRE6), and Providencia stuartii (UPMRG1) using a 16S rRNA technique. The selected strains were inoculated to three different rice varieties, namely BRRI dhan67 (salt-tolerant), Putra-1 (moderate salt-tolerant), and MR297 (salt-susceptible) under glasshouse conditions. Results showed that the MR297 rice variety inoculated with UPMRB9 produced the highest total chlorophyll content, with an increment of 28%, and lowest electrolyte leakage of 92%. The Putra-1 rice variety also showed a 156% total dry matter increase with the inoculation of this bacterial strain. The highest increase of relative water content and reduction of Na/K ratio were found upon inoculation of UPMRE6 and UPMRB9, respectively. The biggest significant effects of these bacterial inoculations were on relative water content, electrolyte leakage, and the Na/K ratio of the BRRI dhan67 rice variety under saline conditions, suggesting a synergistic effect on the mechanisms of plant salt-tolerance. This study has shown that the application of locally-isolated salt-tolerant PGPR strains could be an effective long-term and sustainable solution for rice cultivation in the coastal areas, which are affected by global climate change.
Highlights
Plant growth and productivity are being hampered by various biotic and abiotic stresses [1]
UPMRB9 produced the highest amount of exopolysaccharide (EPS) at 1.5 M of NaCl (30.50 g L−1 ), which is significantly higher than UPMRG1, UPMRE3, and UPMRA4 (Table 1 and Scheme 1)
plant growth-promoting rhizobacteria (PGPR) strains on the growth of rice plant under glasshouse conditions
Summary
Plant growth and productivity are being hampered by various biotic and abiotic stresses [1]. Salinity is regarded as one of the important agricultural problems, as it affects more than 20% of the total and irrigated land [2]. Rice is a glycophyte plant by nature; it is inherently prone to salinity and will show a wide and vivid detrimental response to an increased salt level in the soil [3]. Several physical and chemical strategies for salinity mitigation have been tested but these methods are not feasible, causing adverse impacts on the ecosystem, thereby creating other problems. Identifying and developing an eco-friendly strategy that can ameliorate plant growth in response to abiotic stresses is vital in the current agricultural systems, which have to cope with the effect of climate change [4]
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 call
