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

Abstract

Different physical and chemical techniques are used for the decontamination of Cr+6 contaminated sites. The techniques are expensive, laborious, and time-consuming. However, remediation of Cr+6 by microbes is viable, efficient, and cost-effective. In this context, plant growth-promoting rhizobacteria Acinetobacter bouvetii P1 isolated from the industrial zone was tested for its role in relieving Cr+6 induced oxidative stress in sunflower. At the elevated Cr+6 levels and in the absence of P1, the growth of the sunflower plants was inhibited. In contrast, the selected strain P1 restored the sunflower growth under Cr+6 through plant growth–promoting interactions. Specifically, P1 biotransformed the Cr+6 into a stable and less toxic Cr+3 form, thus avoiding the possibility of phytotoxicity. On the one hand, the P1 strengthened the host antioxidant system by triggering higher production of enzymatic antioxidants, including catalases, ascorbate peroxidase, superoxide dismutase, and peroxidase. Similarly, P1 also promoted higher production of nonenzymatic antioxidants, such as flavonoids, phenolics, proline, and glutathione. Apart from the bioremediation, P1 solubilized phosphate and produced indole acetic acid, gibberellic acid, and salicylic acid. The production of phytohormones not only helped the host plant growth but also mitigated the harsh condition posed by the elevated levels of Cr+6. The findings mentioned above suggest that P1 may serve as an excellent phyto-stimulant and bio-remediator in a heavy metal-contaminated environment.

Improving yield of Barley using bio and nano fertilizers under saline conditions

“…Both strains of bacteria used are positive producers of proline, under saline medium in vitro. The proline produce by Acinetobacter baumannii was 9.1 ppm and by Brevundimonas olei was 7.4 ppm, this agrees with Qadir et al, (2021), who studied that the Acinetobacter bouvetii P1 boosted sunflower by increasing the ________________________________________________ Egypt. J.…”

Aspergillus violaceofuscus alleviates cadmium and chromium stress in Okra through biochemical modulation

“…The use of microbes to help the crop plants in the HMs contaminated soils is considered to be more practical, easy, cost effective and safe to the ecosystem [4,9,25]. Exploration of beneficial microbes, such as endophytes (microbes live in symbiotic relations with host plants) and their application in HMs contaminated soils can lead to a sustainable agriculture and access to a safer food [4,16,40]. Qadir, et al [8] observed Cr remediation potential of endophytic Aspergillus niger in sunflower.…”

Endophytic fungi isolated from plants present in a mine tailing facility show a differential growth response to lead

“…Certainly, Pb tolerance is only one of the factors involved in fungal behaviour. For instance, interactions between plants and their endophytic organisms can alter the concentration of phytoregulatory compounds and antioxidant responses (Qadir et al 2021(Qadir et al , 2022. These aspects can be relevant as the focus of future studies to determine if phytoremediation assisted by endophytic fungi in similar environments of cold steppe could become a viable strategy.…”