Deciphering Staphylococcus sciuri SAT-17 Mediated Anti-oxidative Defense Mechanisms and Growth Modulations in Salt Stressed Maize (Zea mays L.)

Abstract

Soil salinity severely affects plant nutrient use efficiency and is a worldwide constraint for sustainable crop production. Plant growth-promoting rhizobacteria, with inherent salinity tolerance, are able to enhance plant growth and productivity by inducing modulations in various metabolic pathways. In the present study, we reported the isolation and characterization of a salt-tolerant rhizobacterium from Kallar grass [Leptochloa fusca (L.) Kunth]. Sequencing of the 16S rRNA gene revealed its lineage to Staphylococcus sciuri and it was named as SAT-17. The strain exhibited substantial potential of phosphate solubilization as well as indole-3-acetic acid production (up to 2 M NaCl) and 1-aminocyclopropane-1-carboxylic acid deaminase activity (up to 1.5 M NaCl). Inoculation of a rifampicin-resistant derivative of the SAT-17 with maize, in the absence of salt stress, induced a significant increase in plant biomass together with decreased reactive oxygen species and increased activity of cellular antioxidant enzymes. The derivative strain also significantly accumulated nutrients in roots and shoots, and enhanced chlorophyll and protein contents in comparison with non-inoculated plants. Similar positive effects were observed in the presence of salt stress, although the effect was more prominent at 75 mM in comparison to higher NaCl level (150 mM). The strain survived in the rhizosphere up to 30 days at an optimal population density (ca. 1 × 106 CFU mL-1). It was concluded that S. sciuri strain SAT-17 alleviated maize plants from salt-induced cellular oxidative damage and enhanced growth. Further field experiments should be conducted, considering SAT-17 as a potential bio-fertilizer, to draw parallels between PGPR inoculation, elemental mobility patterns, crop growth and productivity in salt-stressed semi-arid and arid regions.

A phytobeneficial strainPlanomicrobiumsp. MSSA-10 triggered oxidative stress responsive mechanisms and regulated the growth of pea plants under induced saline environment

“…Three NaCl levels (0, 75 or 150 mmol l À1 ) were maintained while irrigating the pots with canal water or Hoagland solution making six experimental groups i.e. UN0 (un-inoculated soil having 0 mmol l À1 NaCl), UN75 (un-inoculated soil having 75 mmol l À1 NaCl), UN150 (un-inoculated soil having 150 mmol l À1 NaCl), IN0: (MSSA-10 rif inoculated soil having 0 mmol l À1 NaCl), IN75 (MSSA-10 rif inoculated soil having 75 mmol l À1 NaCl), IN150 (MSSA-10 rif inoculated soil having 150 mmol l À1 NaCl) (Akram et al 2016). After seedling emergence, the plants were thinned to five plants per pot and periodic irrigation was maintained using canal water.…”

“…; Akram et al . ). It has been established that PGPR‐assisted improvement of salt effected soil is one of the promising approaches for utilization of such soils for crop cultivation (Dodd and Pérez‐Alfocea ).…”

“…This has also led to development of microbe-assisted soil reclamation strategies. Rhizobacteria release growth promoting factors, enhance mobilization of soil-bound minerals (making them available to plants), possess 1 aminocyclopropane-1-carboxylicacid (ACC) deaminase activity and induce up-regulation of genes involved in coping the abiotic and biotic stresses (Hanif et al 2015;Hussain et al 2015;Shahid et al 2015;Akram et al 2016). It has been established that PGPR-assisted improvement of salt effected soil is one of the promising approaches for utilization of such soils for crop cultivation (Dodd and P erez-Alfocea 2012).…”

Serratiasp.CP‐13 augments the growth of cadmium (Cd)‐stressedLinum usitatissimumL. by limited Cd uptake, enhanced nutrient acquisition and antioxidative potential

“…A major physiological change in plants, interacting with PGPB under stress conditions, is a decrease in ethylene level due to the activity of 1‐aminocyclopropane‐1‐carboxylic acid (ACC) deaminase (Akram et al . ; Mahmood et al . ).…”

“…Moreover, a cellular decrease in the levels of reactive oxygen species (ROS) and increase in the levels of antioxidants were observed after PGPB inoculation (Akram et al . ; Israr et al . ; Khan et al .…”