Due to the high migration capacity in agricultural soil-crop systems, cadmium (Cd) is accumulated in various crops and severely inhibits plant growth. In this study, we showed that, under Cd stress, the plant-symbiotic fungus Metarhizium robertsii reduced Cd accumulation in Arabidopsis thaliana shoots and roots by 21.8 % and 23.8 %, respectively. This is achieved by M. robertsii colonization-induced elevation of Cd efflux capacity via upregulation of three PCR genes, which is confirmed by the fact that the extent to which M. robertsii reduced Cd accumulation in the WT plants was greater than the inactivating mutants of the PCR genes. M. robertsii also alleviated Cd-induced leaf etiolation in A. thaliana by increasing the chlorophyll amount and modified plant physiological status to increase Cd stress tolerance via increasing production of catalase, peroxidase and glutathione and upregulating multiple HIPP proteins involved in sequestration of Cd. Notably, consistent with that in A. thaliana, the colonization of M. robertsii also reduced the Cd accumulation in Oryza sativa seedlings by upregulating the PCR gene OsPCR1, and increased chlorophyll amount and alleviated oxidative stress. Therefore, M. robertsii colonization reduced Cd accumulation in plants, and promoted plant growth and health by elevating Cd efflux capacity and modifying physiological status.

由于农业土壤作物系统的高迁移能力，镉（Cd）在各种作物中积累并严重抑制植物生长。在本研究中，我们发现，在 Cd 胁迫下，植物共生真菌绿僵菌分别减少了拟南芥芽和根中 Cd 的积累 21.8% 和 23.8%。这是通过M. robertsii定殖诱导的 Cd 外排能力的升高通过三个PCR基因的上调来实现的，这一事实证实了M. robertsii减少 WT 植物中 Cd 积累的程度大于灭活突变体PCR基因。M. robertsii还通过增加过氧化氢酶、过氧化物酶和谷胱甘肽的产量以及上调参与螯合 Cd 的多种 HIPP 蛋白来增加叶绿素含量和改变植物生理状态以增加 Cd 胁迫耐受性，从而减轻 Cd 诱导的拟南芥叶片黄化。值得注意的是，与拟南芥中的情况一致，罗伯氏菌的定殖也通过上调PCR基因OsPCR1减少了水稻幼苗中Cd的积累，增加了叶绿素的含量，减轻了氧化应激。因此，M. robertsii定植减少了植物中镉的积累，并通过提高镉外排能力和改变生理状态来促进植物的生长和健康。