Effect of Heavy-Metal-Resistant PGPR Inoculants on Growth, Rhizosphere Microbiome and Remediation Potential of Miscanthus × giganteus in Zinc-Contaminated Soil

Abstract

Microbial-assisted phytoremediation is considered a more effective approach to soil rehabilitation than the sole use of plants. Mycolicibacterium sp. Pb113 and Chitinophaga sp. Zn19, heavy-metal-resistant PGPR strains originally isolated from the rhizosphere of Miscanthus × giganteus, were used as inoculants of the host plant grown in control and zinc-contaminated (1650 mg/kg) soil in a 4-month pot experiment. The diversity and taxonomic structure of the rhizosphere microbiomes, assessed with metagenomic analysis of rhizosphere samples for the 16S rRNA gene, were studied. Principal coordinate analysis showed differences in the formation of the microbiomes, which was affected by zinc rather than by the inoculants. Bacterial taxa affected by zinc and the inoculants, and the taxa potentially involved in the promotion of plant growth as well as in assisted phytoremediation, were identified. Both inoculants promoted miscanthus growth, but only Chitinophaga sp. Zn19 contributed to significant Zn accumulation in the aboveground part of the plant. In this study, the positive effect of miscanthus inoculation with Mycolicibacterium spp. and Chitinophaga spp. was demonstrated for the first time. On the basis of our data, the bacterial strains studied may be recommended to improve the efficiency of M. × giganteus phytoremediation of zinc-contaminated soil.

Effect of ZnO nanoparticle application on crop safety and soil environment: a case study of potato planting

“…Many identified taxa are involved in Zn remediation in soils, including members of Bacillus , Sphingomonas , and Pseudomonas . 50 Similarly, Liu et al 51 observed increased Sphingomonas , Subgroup_7 , and Microscillaceae abundance after ZnO NP supplementation.…”

Characterization of Rhizosphere Microbial Diversity and Selection of Plant-Growth-Promoting Bacteria at the Flowering and Fruiting Stages of Rapeseed

“…Heavy-metal toxicity in soil constitutes a substantial hazard to all living beings in the environment [ 48 , 49 ]. Thus, PGPR-assisted bioremediation is a promising, eco-friendly, and sustainable method for eradicating heavy metals [ 50 ]. PGPR strains with heavy-metal resistance belonged to 12 taxa ( Bacillus sp., Bacillus subtilis , Priestia aryabhattai , Priestia megaterium , Pseudomonas flavescens , Pseudomonas reinekei , Pseudomonas sp., Pseudomonas frederiksbergensis , Lelliottia amnigena , Klebsiella sp.…”

Progress in Microbial Fertilizer Regulation of Crop Growth and Soil Remediation Research

“…Pb113 and Chitinophaga sp. Zn19 Heavy metal-contaminated soil Two inoculants promote manzanita growth and improve soil zinc pollution remediation efficiency [167] plant growth-promoting rhizobacterium strain MD36 Heavy metal-contaminated soil Strain MD36 effectively improves growth and yield of heavy metal-contaminated soils and bioremediation of HM-contaminated saline soils and water [137] Stenotrophomonas maltophilia Cadmium (Cd)-contaminated soil…”