Pseudocitrobacter anthropi reduces heavy metal uptake and improves phytohormones and antioxidant system in Glycine max L.

Abstract

Heavy metal contamination due to anthropogenic activities is a great threat to modern humanity. A novel and natural technique of bioremediation using microbes for detoxi cation of HMs while improving plants' growth is the call of the day. In this study, exposing soybean plants to different concentrations (i.e., 10 and 50 µg/mL) of chromium and arsenic showed a severe reduction in agronomic attributes, higher ROS production, and disruption in the antioxidant system. Contrarily, rhizobacterial isolate C18 inoculation not only rescued host growth, but also improved the production of nonenzymatic antioxidants (i.e., avonoids, phenolic and proline contents) and enzymatic antioxidants (i.e., CAT, APX, POD, and DPPH), higher ROS scavenging, and lower ROS accumulation. Thereby, lowering secondary oxidative stress and subsequent damage. The strain was identi ed using 16S rDNA sequencing, and was identi ed as Pseudocitrobacter anthropi. Additionally, the strain can endure metals up to 1200 µg/mL and e cient in detoxifying the effect of Cr and As, by regulating phytohormones (IAA 59.02 μg/mL and GA 101.88 nM/mL) and solubilizing inorganic phosphates, making them excellent phytostimulant, biofertilizers, and heavy metal bio-remediating agent.

EDTA and IAA Ameliorates Phytoextraction Potential and Growth of Sunflower by Mitigating Cu-Induced Morphological and Biochemical Injuries

“…In a study with Brassica napus , the application of EDTA improved biomass of B. napus in a Cu-amended hydroponic system [ 32 ]. Our findings are in positive correlation with the previous studies, as the synergistic combination of IAA and EDTA significantly reduced Cu-induced toxicity in sunflower seedlings, possibly through reducing Cu-induced oxidative damage, and thus enhanced the morphological features of the tested plants [ 33 , 34 , 35 , 36 ]. In the case of chlorophyll contents, a decline was recorded up to 75 mg/kg of copper stress.…”

“…An interesting contrast was observed with APX, showing a direct proportional and several-fold increase with copper supplementations in the growth medium, and higher enzyme units were observed at 75 mg Cu/kg soil, implying that Cu stimulates the oxidative capacity, which is responsible for the conversion of H 2 O 2 to water and O 2 . APX is a component of the ascorbate-glutathione pathway, which plays a role in scavenging H 2 O 2 [ 34 , 57 ]. Interestingly, an abrupt dip was recorded in the production of ascorbate peroxidase with the supplementation of EDTA in growth medium, except for 75 mg Cu/kg soil, which showed a significant increase.…”

Phytohormones Producing Acinetobacter bouvetii P1 Mitigates Chromate Stress in Sunflower by Provoking Host Antioxidant Response

“…The capacity of P1 to enhance the vegetative attributes of sunflower seedlings stressed by Cr +6 implied that chromate detoxification and limited absorption are not the predominant phytostimulation process. Moreover, increased storage of enzymatic antioxidants (CAT, APX, POD, and SOD) along with reduced glutathione (nonenzymatic) may have scavenged the generated ROS in plants more efficiently to support their defensive mechanisms [ 90 ]. Evidence of improved ROS scavenging ability of rhizobacterium associated sunflower seedlings was linked to the effective DPPH quenching potential and reduced ROS accumulation.…”

At the core of salinity: convergent and divergent transcriptome response pathways to neutral and alkaline salinity in natural populations ofArabidopsis thaliana

“…This supports a negative regulatory feedback loop occurring after long exposure to alkaline salinity to turn off the transcriptional reprogramming caused by JA accumulation under alkSAL and to minimize JA inhibition on plant growth, in an attempt of acclimation (Riemann et al, 2015). In turn, the stimulation of ABA signaling and accumulation, and the NaCl tolerance observed in coastal demes under neuSAL are likely mediated by WRKYs (Hussain et al, 2021), which remained active after 2 weeks of neuSAL treatment. Among them, enhancers of the osmotic, ROS and hormone signaling pathways under salinity stress have been recently reported (Price et al, 2022).…”