title: Characterization of Mn-resistant endophytic bacteria from Mn-hyperaccumulator Phytolacca americana and their impact on Mn accumulation of hybrid penisetum.
abstract: Three hundred Mn-resistant endophytic bacteria were isolated from the Mn-hyperaccumulator, Phytolacca americana, grown at different levels of Mn (0, 1, and 10mM) stress. Under no Mn stress, 90%, 92%, and 11% of the bacteria produced indole acetic acid (IAA), siderophore, and 1-aminocyclopropane-1-carboxylate (ACC) deaminase, respectively. Under Mn stress, 68-94%, 91-92%, and 21-81% of the bacteria produced IAA, siderophore, and ACC deaminase, respectively. Greater percentages of ACC deaminase-producing bacteria were found in the Mn-treated P. americana. Furthermore, the ratios of IAA- and siderophore-producing bacteria were significantly higher in the Mn treated plant leaves, while the ratio of ACC deaminase-producing bacteria was significantly higher in the Mn treated-roots. Based on 16S rRNA gene sequence analysis, Mn-resistant bacteria were affiliated with 10 genera. In experiments involving hybrid penisetum grown in soils treated with 0 and 1000mgkg(-1) of Mn, inoculation with strain 1Y31 was found to increase the root (ranging from 6.4% to 18.3%) and above-ground tissue (ranging from 19.3% to 70.2%) mass and total Mn uptake of above-ground tissues (64%) compared to the control. Furthermore, inoculation with strain 1Y31 was found to increase the ratio of IAA-producing bacteria in the rhizosphere and bulk soils of hybrid penisetum grown in Mn-added soils. The results showed the effect of Mn stress on the ratio of the plant growth-promoting factor-producing endophytic bacteria of P. americana and highlighted the potential of endophytic bacterium as an inoculum for enhanced phytoremediation of Mn-polluted soils by hybrid penisetum plants.
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture; College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture; College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture; College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China.
authors.forename: Lin-Yan
authors.initials: LY
authors.lastname: He
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture; College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.affiliation: Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture; College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu, People's Republic of China. Electronic address: xfsheng@njau.edu.cn.
authors.forename: Xia-Fang
authors.initials: XF
authors.lastname: Sheng
mesh_terms: D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D001673:Biodegradation, Environmental; D019755:Carbon-Carbon Lyases / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D007210:Indoleacetic Acids / Q000378:metabolism; D008345:Manganese / Q000378:metabolism*; D029604:Phytolacca americana / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics / Q000302:isolation & purification*; D058441:Rhizosphere; D017262:Siderophores / Q000378:metabolism; D012988:Soil Microbiology
chemical_list: D004269:DNA, Bacterial; D007210:Indoleacetic Acids; D012336:RNA, Ribosomal, 16S; D017262:Siderophores; D008345:Manganese; C030737:indoleacetic acid; C033634:1-aminocyclopropane-1-carboxylate deaminase; D019755:Carbon-Carbon Lyases
keywords: Hybrid penisetum; Mn stress; Mn-hyperaccumulator; Mn-resistant endophytic bacteria; Phytolacca americana; Phytoremediation