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

Abstract

Aims The current study was aimed to evaluate the beneficial effects and bioremediation potential of a Cd‐tolerant bacterial strain, Serratia sp. CP‐13, on the physiological and biochemical functions of Linum usitatissimum L., under Cd stress. Methods and Results The bacterial strain was isolated from the wastewater collection point of Chakera, Faisalabad, Pakistan, as this place contains industrial wastewater of the Faisalabad region. The Serratia sp. CP‐13, identified through 16S rRNA gene sequence analysis, exhibited a significant phyto‐beneficial potential in terms of in vitro inorganic phosphate solubilization, indole‐3‐acetic acid production and 1‐aminocyclopropane‐1‐carboxylic acid deaminase activity. Effects of Serratia sp. CP‐13 inoculation on L. usitatissimum were evaluated by growing the plants in CdCl2 (0, 5 or 10 mg kg−1 dry soil)‐spiked soil. Without inoculation of Serratia sp. CP‐13, Cd stress significantly reduced the plant biomass as well as the quantity of proteins and photosynthetic pigments due to enhanced H2O2, malondialdehyde (MDA) contents and impaired nutrient homeostasis. Subsequently, Serratia sp. CP‐13 increased the plant fresh and dry biomass, plant antioxidation capacity, whereas it decreased the lipid peroxidation under Cd stress. In parallel, Serratia sp. inoculation assisted the Cd‐stressed plants to maintain an optimum level of nutrients (K, Ca, P, Mg, Fe and Mn). Conclusions The isolated bacterial strain (Serratia sp. CP‐13) when applied to Cd‐stressed L. usitatissimum inhibited the Cd uptake, reduced Cd‐induced lipid peroxidation, maintained the optimum level of nutrients and thereby, enhanced L. usitatissimum growth. The analysis of bio‐concentration and translocation factor revealed that L. usitatissimum with Serratia sp. CP‐13 inoculation sequestered Cd in plant rhizospheric zone. Significance and Impact of the Study Serratia sp. CP‐13 inoculation is a potential candidate for the development of low Cd‐accumulating linseed and could be used for phytostabilization of Cd‐contaminated rhizosphere/soil colloids.

Fungal Seed Endophyte FZT214 Improves Dysphania ambrosioides Cd Tolerance Throughout Different Developmental Stages

“…In general, the Cd concentration was relatively less in the aboveground and belowground tissues of E+ plants in most of the treatments ( Table 1 ). This finding was similar to the results of the previous studies that observed lower Cd in inoculated plants than non-inoculated plants ( Wang et al, 2016 ; He et al, 2017 ; Zhan et al, 2017 ; Zhu et al, 2018 ; Shahid et al, 2019 ). However, in this study, the difference was non-significant ( p > 0.05) in most of the tested conditions ( Table 1 ).…”

“…Previous studies have demonstrated that endophytes can enhance host plant growth under Cd stress ( Soleimani et al, 2010 ; Khan et al, 2015 ; Zhu et al, 2018 ; He et al, 2019 ; Shahid et al, 2019 ; Zhang et al, 2019 ). In the present study, it was found that fungal endophyte FZT214 improved D. ambrosioides growth under Cd stress.…”

“…This “dilution mechanism” can be related to the lower Cd toxicity in plant tissue and subsequently increased plant biomass in the inoculated plants ( Guo et al, 2013 ). The induced growth and tolerance by the inoculated endophyte can be due to the relative decrease in metal uptake into the above and belowground tissues and the selective translocation of Cd from roots to aboveground tissues ( Zhu et al, 2018 ; Shahid et al, 2019 ). Generally, metal contents in plant samples are subject to the availability of metals in the soil ( Vivas et al, 2006 ).…”

“…Generally, metal contents in plant samples are subject to the availability of metals in the soil ( Vivas et al, 2006 ). Other possible reasons for lower Cd in the inoculated plants could be Cd sequestration in the root zone, siderophore secretion and production of exopolysaccharides, excretion of Cd from the cell by efflux pumps, and reduced phytotoxicity through secretion of antioxidants ( Shahid et al, 2019 ; Wang et al, 2019 ).…”

“… Khan et al (2017) reported greater Cd contents in the Solanum nigrum roots, which suggest the role of these plants as a phytostabilizer. More Cd accumulation in the belowground tissue also indicates that the roots are the major site for storage of metals ( Shahid et al, 2019 ).…”