Department of Botany, PMAS-Arid Agriculture University, Rawalpindi 46300, Pakistan.
Department of Biosciences, COMSATS University, Islamabad (CUI), Islamabad 46300, Pakistan.
Molecules. 2021 Mar 12;26(6):1569. doi: 10.3390/molecules26061569.
Plant growth-promoting rhizobacteria (PGPR) mediate heavy metal tolerance and improve phytoextraction potential in plants. The present research was conducted to find the potential of bacterial strains in improving the growth and phytoextraction abilities of (L.) K. Koch. in chromium contaminated soil. In this study, a total of 15 bacterial strains were isolated from heavy metal polluted soil and were screened for their heavy metal tolerance and plant growth promotion potential. The most efficient strain was identified by 16S rRNA gene sequencing and was identified as . The isolate also showed the potential to solubilize phosphate and synthesize siderophore, phytohormones (indole acetic acid, cytokinin, and abscisic acid), and osmolyte (proline and sugar) in chromium (Cr) supplemented medium. The results of the present study showed that chromium stress has negative effects on seed germination and plant growth in while inoculation of improved plant growth and reduced chromium toxicity. The increase in seed germination percentage, shoot length, and root length was 28.07%, 35.86%, 19.11% while the fresh and dry biomass of the plant increased by 48.00% and 62.16%, respectively, as compared to the uninoculated/control plants. The photosynthetic pigments were also improved by bacterial inoculation as compared to untreated stress-exposed plants, i.e., increase in chlorophyll a, chlorophyll b, chlorophyll a + b, and carotenoid was d 25.94%, 10.65%, 20.35%, and 44.30%, respectively. Bacterial inoculation also resulted in osmotic adjustment (proline 8.76% and sugar 28.71%) and maintained the membrane stability (51.39%) which was also indicated by reduced malondialdehyde content (59.53% decrease). The antioxidant enzyme activities were also improved to 35.90% (superoxide dismutase), 59.61% (peroxide), and 33.33% (catalase) in inoculated stress-exposed plants as compared to the control plants. inoculation also improved the uptake, bioaccumulation, and translocation of Cr in the plant. Data showed that also increased Cr content in the root (2.71-fold) and shoot (4.01-fold), its bioaccumulation (2.71-fold in root and 4.03-fold in the shoot) and translocation (40%) was also high in . The data revealed that is a multifarious PGPR that efficiently tolerates heavy metal ions (Cr) and it can be used to enhance the growth and phytoextraction potential of in heavy metal contaminated soil.
植物促生根际细菌（PGPR）介导重金属耐受性并提高植物的植物提取潜力。本研究旨在寻找细菌菌株的潜力，以提高在铬污染土壤中 的生长和植物提取能力。在这项研究中，从重金属污染的土壤中分离出了 15 株细菌菌株，并对其重金属耐受性和植物生长促进潜力进行了筛选。通过 16S rRNA 基因测序鉴定最有效的菌株，并鉴定为 。该分离株还表现出在铬（Cr）补充培养基中溶解磷酸盐和合成铁载体、植物激素（吲哚乙酸、细胞分裂素和脱落酸）和渗透物（脯氨酸和糖）的潜力。本研究结果表明，铬胁迫对 的种子萌发和植物生长有负面影响，而 的接种改善了植物生长并降低了铬毒性。与未接种/对照植物相比，种子萌发率、茎长和根长分别增加了 28.07%、35.86%和 19.11%，而植物的鲜重和干重分别增加了 48.00%和 62.16%。与未经处理的应激暴露植物相比，细菌接种还改善了光合色素，即增加了叶绿素 a、叶绿素 b、叶绿素 a+b 和类胡萝卜素分别为 25.94%、10.65%、20.35%和 44.30%。细菌接种还导致渗透调节（脯氨酸 8.76%和糖 28.71%）并维持膜稳定性（51.39%），这也表现为丙二醛含量降低（降低 59.53%）。与对照植物相比，接种应激暴露植物的抗氧化酶活性也提高了 35.90%（超氧化物歧化酶）、59.61%（过氧化物酶）和 33.33%（过氧化氢酶）。 接种还提高了植物对 Cr 的吸收、生物积累和转运。数据显示， 还增加了根（2.71 倍）和茎（4.01 倍）中的 Cr 含量，其生物积累（根中 2.71 倍，茎中 4.03 倍）和转运（40%）也很高。数据表明， 是一种能够有效耐受重金属离子（Cr）的多功能 PGPR，可用于提高 在重金属污染土壤中的生长和植物提取潜力。
