Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-ku, 6-6-20 Aoba, Sendai 980-8579, Japan.
Graduate School of Environmental Studies, Tohoku University, Aramaki, Aoba-ku, 6-6-20 Aoba, Sendai 980-8579, Japan; Institute of Marine Biology and Center of Excellence for the Oceans, National Taiwan Ocean University, 2 Pei-Ning Road, Keelung 20224, Taiwan.
Sci Total Environ. 2020 Apr 10;712:134504. doi: 10.1016/j.scitotenv.2019.134504. Epub 2019 Oct 8.
Pteris vittata and Pteris multifida are widely studied As hyperaccumulators that absorb As mainly via roots. Hence, rhizobacteria exhibit promising potential in phytoextraction owing to their immense microbial diversity and interactions with plants. Pseudomonas vancouverensis strain m318 that contains aioA-like genes was screened from P. multifida's rhizosphere through the high As resistance (minimum inhibitory concentrations (MICs) against As(III): 16 mM; MICs against As(V): 320 mM), rapid As oxidation (98% oxidation by bacterial cultures (OD = 1) from 200 μL of 0.1 mM As(III) within 24 h), predominant secretion of IAA (12.45 mg L) and siderophores (siderophore unit: 88%). Strain m318 showed significant chemotactic response and high colonization efficiency to P. vittata roots, which suggested its wide host affinity. Interestingly, inoculation with strain m318 enhanced the proportion of aioA-like genes in the rhizosphere. And in field trials, inoculation with strain m318 increased As accumulation in P. vittata by 48-146% and in P. multifida by 42-233%. Post-transplantation inoculations also increased As accumulation in both ferns. The abilities of the isolated multifunctional strain m318 and the increase in the rhizosphere microbial aioA-like genes are thus speculated to be involved in As transformation in the rhizospheres and roots of P. vittata and P. multifida.
凤尾蕨和蜈蚣草是广泛研究的砷超富集植物，主要通过根部吸收砷。因此，根际细菌由于其巨大的微生物多样性和与植物的相互作用，在植物提取中具有很大的应用潜力。从蜈蚣草根际筛选出一株含有 aioA 样基因的假单胞菌菌株 m318，该菌对砷的抗性很强（对 As(III)的最小抑菌浓度（MICs）：16 mM；对 As(V)的 MICs：320 mM），能快速氧化砷（细菌培养物（OD=1）在 24 小时内从 200μL 的 0.1mM As(III)中氧化 98%），主要分泌 IAA（12.45mg/L）和铁载体（铁载体单位：88%）。菌株 m318对凤尾蕨根表现出显著的趋化响应和高定植效率，这表明其具有广泛的宿主亲和力。有趣的是，接种菌株 m318 增加了根际的 aioA 样基因比例。在田间试验中，接种菌株 m318 使凤尾蕨中砷的积累增加了 48-146%，使蜈蚣草中砷的积累增加了 42-233%。移栽后接种也增加了两种蕨类植物中砷的积累。因此，推测分离的多功能菌株 m318 及其根际微生物 aioA 样基因的增加参与了凤尾蕨和蜈蚣草根际和根部的砷转化。
