Augmentative role of Piriformospora indica fungus and plant growth promoting bacteria in mitigating salinity stress in Trigonella foenum-graecum

Abstract

An experiment was conducted to evaluate the role of Piriformospora indica and plant growth promoting bacteria (PGPB) in mitigating salinity stress in Trigonella foenum graecum. Plants were subjected to three different levels of salinity, viz., 0, 70, and 150 mM NaCl (electrical conductivity value 0.01, 7.67, and 15.50 mS cm −1 , respectively) using a completely randomized design experiment. The P. indica and PGPB showed positive effects in mitigation of salinity stress in fenugreek plants and elevated various growth responses, viz., shoot and root length, shoot and root dry weight, leaf area, and number of leaves as compared to uninoculated plants. Microbial inoculation significantly enhanced the physiological responses, viz., photosynthetic rate, stomatal conductance, transpiration and internal CO 2 as compared to uninoculated plants. Biochemical aspects like carotenoids, chlorophylls, nitrogen, and protein content were also increased in the microbial inoculated plants as compared to uninoculated plants. However, PGPB was more effective than P. indica in mitigating salinity stress in fenugreek plant. The findings of this study revealed that P. indica and PGPB inoculation can help the plants to overcome the deleterious effects of salinity stress in fenugreek plants.Horticultural crops (spinach, potatoes, tomatoes, and lettuce) and cereals (maize, wheat, rice, and legumes) are sensitive to salinity stress which reduces the yield up to 50%-75% [5]. A plant that is under the influence of salt stress goes through series of morphological, physiological, and molecular modifications, eventually obstructing its maturation [10]. Photosynthesis is affected by soil salinity, which results in a reduction in leaf area. With extended salt tension, old

A plant’s perception of growth-promoting bacteria and their metabolites

“…Similar results on the photosynthetic activity were obtained by Bisht et al. (2022) in fenugreek plants grown under moderate salinity (70 and 150 mM NaCl) after inoculation with a microbial consortium including Azotobacter chroococcum , Enterobacter asburiae , and Lactococcus lactis .…”

“…The accumulation of osmolytes and enzymatic activities were responsible for a decrease in oxidative stress by regulating the steady-state concentration of ROS (malondeadehyde, H 2 O 2 , and O 2 -). Similar results on the photosynthetic activity were obtained by Bisht et al (2022) in fenugreek plants grown under moderate salinity (70 and 150 mM NaCl) after inoculation with a microbial consortium including Azotobacter chroococcum, Enterobacter asburiae, and Lactococcus lactis. Also, in this PGPRplant interaction, the increased photosynthetic rate was coupled with higher stomatal conductance, transpiration, intercellular CO 2 concentration, chlorophyll a and total chlorophyll, carotenoids, compared to non-inoculated plant, with a consequent increase in shoot and root dry weight (Supplementary Table S2).…”

“…Thus, root traits are shaped by nutrient availability, water, and environmental gradients, and by the biotic interaction with other plants, with the soil fauna, and with microorganisms ( Grover et al., 2021 ). PGPR have been reported to change the root architecture deeply by enhancing root elongation ( Shahzad et al., 2014 ; Kumari et al., 2015 ; Wang et al., 2015 ; Bisht et al., 2022 ), belowground biomass ( Ait Barka et al., 2006 ; Bresson et al., 2013 ; Naveed et al., 2014 ), lateral roots ( Mantelin et al., 2006 ; Contesto et al., 2010 ; Kumari et al., 2015 ), improving root acquisition of nutrients and water ( Grover et al., 2021 ). One of the most important microbial drivers inducing root trait modifications is the capability of certain PGP strains to excrete plant hormones, which stimulate plant growth ( Castro and Bucio, 2013 ).…”

“…Apart from the abovementioned studies, other findings with different Fabaceae species and bacterial inoculants indicate that PGPR can enhance plant growth and photosynthetic activity. In a pot experiment aiming to evaluate the effect of a consortium of three PGPRs on the germination and growth of Trigonella foenum-grecum , Bisht et al. (2022) reported an increase in CO 2 assimilation rate induced by higher stomatal conductance and higher content of photosynthetic pigments ( Table 2 ).…”

Interaction studies of Serendipita indica and Zhihengliuella sp. ISTPL4 and their synergistic role in growth promotion in rice

“…Co-inoculation of S. indica and A. chroococcum has been shown to boost Stevia rebaudiana growth by enhancing photosynthetic molecule biosynthesis, resulting in increased chlorophyll, carotenoids, total sugar, and protein levels ( Kumar Bhuyan et al., 2015 ). Co-inoculation of S. indica and PGPB ( Enterobacter asburiae , Lactococcus lactis , and A. chroococcum ) improved the growth of Trigonella foenum-graecum by increasing the photosynthetic yield, transpiration rate, stomatal conductance, and internal CO 2 ( Bisht et al., 2022 ). Plant growth-promoting bacteria help in the synthesis of phytohormones such as auxin, which is involved in coleoptile elongation during submergence ( Ahumada et al., 2022 ).…”