Reactive oxygen species (ROS) scavenging and methylglyoxal (MG) detoxification confers salinity tolerance in mustard cultivars inoculated with Piriformospora (Serendipita) indica.

Salinization has become a major concern for the growth and development of plants, resulting in significant crop losses. Beneficial microbial symbionts are utilized as promising tools in alleviation of adverse effects of salt stress. Piriformospora (Serendipita) indica is one of the cost-effective, eco-friendly, and stress relieving biostimulant that positively regulates the growth of a broad host range of plants. The present study was to investigate the impact of P. indica on Indian mustard (Brassica juncea L.) cultivars (Pusa Jaikisan and Pusa Bold) under different levels of salinity stress (0, 50, 100, 150, 200 and 300 mM NaCl) by analyzing morphological, physiological and biochemical attributes. Results revealed that the plant biomass, chlorophyll content, and relative water content were reduced and Na+ and Cl‒ ions uptake increased with increasing NaCl concentrations. The maximum reduction in the measured traits was observed at 300 mM NaCl in both cultivars [tolerant (Pusa Jaikisan) and sensitive (Pusa Bold)]. Additionally, the oxidative stress markers (TBARS, MG, H 2 O 2, and EL) accumulation were increased with increasing salt concentrations. However, P. indica colonization enhanced the plant performance by improving the biomass, chlorophyll, and water content, and reduced levels of oxidative stress markers (TBARS, MG, H 2 O 2, and EL) in both cultivars comparatively more in Pusa Jaikisan than Pusa Bold under salinity stress. Additionally, the maximum activities of methyl glyoxal detoxifying enzymes (Gly I & Gly II) along with the components of ROS scavenging machinery (SOD, APX, GPX, GR, AsA, and GSH) in the P. indica colonized plants conferred salt tolerance in comparison to non-colonized cultivars under salinity stress. The results indicate that P. indica promotes the growth and tolerance of mustard plants under salinity stress, thus providing opportunity for further assessment in terms of use in sustainable agriculture. [Display omitted] • Salinity stress can disrupt normal growth and development of plants thus pose serious threat to the global agriculture and cause significant yield loss. • Salinity induced production reactive oxygen species (ROS) and methyl glyoxal (MG) cause oxidative stress which disrupts the vital metabolic pathways. • Piriformospora (syn. Serendipita, Basidiomycota) indica colonized plants showed improved photosynthetic characteristics, physiological and morphological characteristics in mustard plants under salinity stress. • P. indica, acts as potential biostimulant thus confers salinity tolerance by regulating the ROS metabolism and MG detoxification in Brassica. [ABSTRACT FROM AUTHOR]