Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, People's Republic of China.
Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin, 300191, People's Republic of China.
Chemosphere. 2020 Aug;252:126603. doi: 10.1016/j.chemosphere.2020.126603. Epub 2020 Mar 24.
Microbial remediation of heavy metal-polluted soil is a commonly used method. Burkholderia sp. Y4, isolated from cadmium (Cd)-contaminated rice rhizosphere soil, was investigated for its direct and indirect effects on Cd accumulation in rice by SEM-EDS, FITR and sequencing analysis of the soil bacterial community. Burkholderia sp. Y4 inoculation reduced Cd accumulation in rice roots, rachises, and grains of the two rice varieties T705 and X24 and increased levels of essential elements, especially Fe and Mn, which competitively inhibited Cd transport through cationic channels. Living Burkholderia sp. Y4 cells, rather than non-living ones, could colonize the surface of rice roots and accumulated more Cd through direct biosorption associated with -CO and -NH/-CO bonds of amino acids and proteins. The results of soil microbial community showed that the colonization of externally added Burkholderia sp. Y4 could be maintained over some time to impact the total rhizospheric environment. Burkholderia sp. Y4 inoculation decreased the abundance of microbes involved in the iron cycle (Acidobacteria) as well as of those mediating the transformation of ammonium nitrogen to nitrate nitrogen (Nitrosomonadaceae and Nitrospira). So Burkholderia sp. Y4 inoculation may indirectly change the availability of micronutrients and Cd in rice rhizosphere soil through iron-nitrogen coupled cycles to increase essential nutrient uptake and inhibit Cd accumulation in rice by preferential Cd-biosorption. Therefore, Burkholderia sp. Y4 is potentially suitable for the bioremediation of Cd-contaminated paddy soil.
微生物修复重金属污染土壤是一种常用的方法。从镉污染水稻根际土壤中分离得到的伯克霍尔德菌 Y4，研究了其对水稻中镉积累的直接和间接影响，采用 SEM-EDS、FITR 和土壤细菌群落测序分析。伯克霍尔德菌 Y4 的接种减少了两个水稻品种 T705 和 X24 的水稻根系、茎和籽粒中 Cd 的积累，并增加了必需元素的水平，特别是 Fe 和 Mn，它们通过阳离子通道竞争抑制 Cd 的运输。活的伯克霍尔德菌 Y4 细胞而不是非活的细胞可以定殖在水稻根表面，并通过与氨基酸和蛋白质的 -CO 和 -NH/-CO 键相关的直接生物吸附积累更多的 Cd。土壤微生物群落的结果表明，外加的伯克霍尔德菌 Y4 的定植可以在一段时间内得以维持，从而影响整个根际环境。伯克霍尔德菌 Y4 的接种减少了参与铁循环的微生物（酸杆菌）的丰度，以及介导铵态氮向硝酸盐氮转化的微生物（硝化单胞菌科和硝化螺旋菌科）的丰度。因此，伯克霍尔德菌 Y4 接种可能通过铁-氮偶联循环间接改变水稻根际土壤中微量元素和 Cd 的有效性，增加必需营养元素的吸收，通过优先 Cd 生物吸附抑制水稻中 Cd 的积累。因此，伯克霍尔德菌 Y4 可能适合用于 Cd 污染稻田的生物修复。
