Catedratico CONACYT, División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Conkal, CP 97345, Conkal, Yucatán, Mexico.
Facultad de Ciencias Físico Matemáticas, Universidad Michoacana de San Nicolás de Hidalgo, Cd. Universitaria, CP 58060, Morelia, Michoacán, Mexico.
Environ Sci Pollut Res Int. 2019 Jan;26(1):381-391. doi: 10.1007/s11356-018-3569-7. Epub 2018 Nov 6.
This work examines the strategies adopted by an arbuscular mycorrhizal symbiotic system to ameliorate environmental Pb stress by examining the concentrations of P, Fe, and Pb in the fungal microstructures and the host's root. In vitro cultures of Ri-T DNA-transformed carrot (Daucus carota L.) roots were inoculated with Glomus intraradices and treated with Pb(NO) solution and the extraradical spores and mycelia (S/M) and the root with the vesicles, mycelia, and root cells were subsequently analyzed by polarized energy dispersive x-ray fluorescence (PEDXRF) spectrometry. Upon Pb treatment, within the root, the percentages of mycorrhizal colonization, the vesicles, and mycelia increased as well as the areas of the vesicles and the (extraradical) spores, although the number of spores and arbuscules decreased. The S/M and the mycorrhizal root showed enhanced concentrations of Pb, Fe, and P. These were particularly marked for Fe in the Pb-treated cultures. This indicates a synergistic relationship between the arbuscular mycorrhizal fungus and the host that confers a higher Pb tolerance to the latter by the induction of higher Fe absorption in the host. The intraradical vesicle, mycelia, and arbuscule numbers are interpreted as a "tactic to divert" the intraradical Pb traffic away from the root cells to the higher affinity cell walls of the arbuscular mycorrhizal fungi (AMF) microstructures in the apoplast. The results of this work show that the symbiosis between the AMF G. intraradices and the host plant D. carota distinctly improves the latter's Pb tolerance, and imply that the appropriate metal tolerant host-AMF combinations could be employed in process designs for the phytoremediation of Pb.
这项工作通过检查真菌微观结构和宿主根中 P、Fe 和 Pb 的浓度，研究了丛枝菌根共生系统采用的策略，以改善环境 Pb 胁迫。用 Ri-T DNA 转化的胡萝卜（Daucus carota L.）根的体外培养物接种了 Glomus intraradices，并进行了 Pb(NO)处理，随后用偏振能量色散 X 射线荧光（PEDXRF）光谱法分析了外生孢子和菌丝（S/M）以及具有泡囊、菌丝和根细胞的根。在 Pb 处理后，在根内，丛枝菌根定殖、泡囊和菌丝的比例增加，泡囊和（外生）孢子的面积增加，尽管孢子和丛枝的数量减少。S/M 和丛枝根表现出增强的 Pb、Fe 和 P 浓度。在 Pb 处理的培养物中，Fe 尤为明显。这表明丛枝菌根真菌和宿主之间存在协同关系，通过诱导宿主更高的 Fe 吸收，赋予后者更高的 Pb 耐受性。根内泡囊、菌丝和丛枝的数量被解释为“策略转移”，将根内的 Pb 流量从根细胞转移到质外体中丛枝菌根真菌（AMF）微观结构的高亲和力细胞壁上。这项工作的结果表明，丛枝菌根真菌 G. intraradices 与宿主植物 D. carota 的共生明显提高了后者的 Pb 耐受性，并暗示适当的金属耐受宿主-AMF 组合可以用于 Pb 的植物修复过程设计。
