Salt-tolerant and plant-growth-promoting bacteria isolated from high-yield paddy soil

Abstract

Growth and productivity of rice is negatively affected by soil salinity. However, some salt-tolerant bacteria improve the health of plants under saline stress. In this study, 305 bacteria were isolated from paddy soil in Taoyuan, China. Among these, 162 strains were tested for salt-tolerance; 67.3%, 28.4%, and 9.3% of the strains could grow in media with NaCl concentrations of 50, 100, and 150 g/L, respectively. The phylogenic analysis of 74 of these 162 strains indicates that these bacteria belong to Bacillales (72%), Actinomycetales (22%), Rhizobiales (1%), and Oceanospirillales (4%). Among 162 strains, 30 salt-tolerant strains were screened for their plant-growth-promoting activities under axenic conditions at 3, 6, 9, and 12 g/L NaCl; 43%-97% of the strains could improve rice germination energy or germination capacity, while 63%-87% of the strains could increase shoot and root lengths. Among various plant-growth-promoting bacteria, TY0307 was the most effective strain for promoting the growth of rice, even at high salt stress. Its promotor effects were associated with its production of 1-aminocyclopropane-1-carboxycarboxylate deaminase, indole acetic acid, and siderophores; induction of proline accumulation; and reduction of the salt-induced malondialdehyde content. These results suggest that several strains isolated from paddy soil could improve rice salt tolerance and may be used in the development of biofertilizer.

Salt-Tolerant Plant Growth Promoting Rhizobacteria for Enhancing Crop Productivity of Saline Soils

“…They found that most of the isolates were able to tolerate up to 8% NaCl and belong to the genus Bacillus. The diversity of salt-tolerant bacteria isolated from paddy rhizosphere in Taoyuan, China was reported by Zhang et al (2018). They isolated 305 bacterial strains, and amongst them, 162 were tested for salt tolerance up to 150 g/l NaCl concentration.…”

Plant Growth-Promoting Bacteria: Biological Tools for the Mitigation of Salinity Stress in Plants

“…A major challenge for world agriculture is to fulfill the food demand of the increasing global population, which is currently growing at a rate of around 1.05% per year ( World Population Prospects, 2019 ). Plant growth, productivity, yield, and food quality are severely influenced by several biotic and abiotic stresses ( Shi-Ying et al, 2018 ; Singh et al, 2018 ). The biotic stresses include damages or infections caused by various pests or pathogens.…”

“…It is estimated that by 2050, about 50% of agricultural land will be salinity affected. Salinization of agricultural land occurs mostly due to the accumulation of salts in soil ( Bharti et al, 2016 ; Shi-Ying et al, 2018 ), particularly sodium (Na + ) and chloride (Cl – ) ions. High Na + accumulation limits water conductance, soil porosity, and aeration.…”

“…Salinity stress also causes oxidative stress by enhancing the production of reactive oxygen species (ROS), which damage cell membranes, proteins, lipids, and nucleic acids (DNA, RNA) and may also induce programmed cell death ( Figure 2 ). Salinity also leads to hypertonic stress due to the excessive accumulation of Na + and Cl – ions ( Shi-Ying et al, 2018 ).…”

“…Further, PGPB also control plant pathogens through the production of antibiotics and competition for the ecological niche and nutrients ( Kumar and Verma, 2018 ). Therefore, the interaction between plant and PGPB is a part of adaptation due to the mutagen effect ( Nautiyal et al, 2008 ; Shi-Ying et al, 2018 ). Thus, to provide a sustainable solution for agriculture and cope up with salinity stress, it is necessary to explore the diversity of the microbes so as to understanding their physiological and functional features and harness their potential.…”