产多胺细菌提高小麦Cd抗性和消减Cd吸收机制

Polyamine-producing Bacteria Improve Cd Resistance and Reduce Uptake of Cd in Wheat

为了探究重金属固定植物促生细菌强化作物消减对重金属的吸收及其机制,以产多胺细菌Enterobacter bugandensis YX6和小麦为研究对象,通过水培试验研究Cd胁迫下菌株YX6对小麦生长和Cd吸收以及Cd在小麦根系中亚细胞分布的影响,同时借助非标记蛋白质组学技术研究菌株YX6对小麦根系蛋白质表达的影响.结果表明,与单独3 mg·L^(-1)Cd处理相比,Cd胁迫下接种菌株YX6显著提高了小麦根(42.71%)和叶片(82.83%)的干重,显著降低了小麦根(48.56%)和叶(61.41%)中Cd的含量.同时,菌株YX6的接种显著提高了小麦根和叶中多胺的含量,进而增强了小麦对Cd的抗性.此外,YX6+Cd处理组中小麦根细胞器和可溶性部分中Cd的比例显著低于单独Cd处理中的比例,而细胞壁中Cd的比例则要高于单独Cd处理中的比例.非标记蛋白质组学显示,Cd胁迫下菌株YX6提高了小麦根系中与DNA修复(蛋白质-DNA复合物和DNA包装复合物)和激素(脱落酸和茉莉酸)合成相关蛋白质的表达,从而提高了小麦对Cd的抗性和消减Cd吸收.结果可为阐明产多胺细菌消减小麦Cd吸收的分子机制和保障小麦安全生产提供科学依据和技术途径.

In order to study the mechanisms of heavy metal-immobilizing and plant growth-promoting bacteria inhibiting the absorption of heavy metals by crops,the polyamine-producing bacteria Enterobacter bugandensis YX6 and wheat were used as the research objects.The effects of strain YX6 on the growth and Cd absorption of wheat and the distribution of Cd in subcells of wheat root were studied using a hydroponic experiment under 3 mg·L^(-1) Cd.Moreover,the effect of strain YX6 on wheat root protein expression was studied using the unlabeled proteomics technique.The results showed that under 3 mg·L^(-1) Cd,strain YX6 significantly increased the dry weight of wheat roots(42.71%)and leaves(82.83%)and reduced the content of Cd in wheat roots(48.56%)and leaves(61.41%).The inoculation of strain YX6 significantly increased the contents of polyamines in wheat roots and leaves and enhanced the resistance to Cd and reduced the absorption of Cd in wheat.In addition,the proportions of Cd in the organelles and soluble parts of wheat roots in the YX6+Cd treatment group were significantly lower than that in the single Cd treatment,whereas the proportion of Cd in the cell wall was higher than that in the single Cd treatment.Unlabeled labeled proteomics showed that under Cd stress,strain YX6 increased the expression of proteins related to DNA repair(protein DNA complex and DNA packaging complex)and hormone(abscisic acid and jasmonic acid)synthesis in wheat roots,thus improving wheat resistance to Cd and reducing Cd absorption.These results provide a theoretical basis and technical way for clarifying the molecular mechanism of polyamine-producing bacteria reducing Cd absorption in wheat and ensuring the safe production of wheat.