Wang Liangyan, Wang Yudong, Dai Shang, Wang Binqiang
Institute of Biophysics, College of Life Sciences, Zhejiang University, Hangzhou 310029, China.
State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310029, China.
Int J Mol Sci. 2024 Nov 22;25(23):12570. doi: 10.3390/ijms252312570.
Cadmium (Cd) and lead (Pb) are the primary hazardous heavy metals that accumulate in crops and pose substantial risks to public health via the food chain. Limiting the migration of these toxic metals from contaminated environments to rice is the most direct and crucial remediation approach. Bioremediation with microorganisms has been extensively utilized for managing heavy metal contamination in the natural environment, and the interplay between microbes and crops is important to alleviate heavy metal stress. Here, we express Lpp-OmpA fused with two metal-binding domains (PbBD and MTT5) in the outer membrane of to enhance both Cd and Pb adsorption. Our results showed that the recombinant strain LOPM, which displayed an increased tolerance to both Cd and Pb stress, exhibited a 4.9-fold higher Cd adsorption and 3.2-fold higher Pb adsorption compared to wild-type strain R1. After LOPM cells colonized the rice root, Cd content reduced to 47.0% in root and 43.4% in shoot; Pb content reduced to 55.4% in root and 26.9% in shoot, as compared to the plant's exposure to Cd and Pb. In addition, cells of LOPM strain colonized on rice roots alleviate Cd- and Pb-induced oxidative stress by reducing ROS levels and enhancing antioxidant enzyme activities in rice. This study supplies a promising application of genetic-engineering extremophile bacteria in reducing heavy metal accumulation and toxicity in rice.
镉（Cd）和铅（Pb）是主要的有害重金属，它们会在作物中积累，并通过食物链对公众健康构成重大风险。限制这些有毒金属从受污染环境向水稻的迁移是最直接且关键的修复方法。利用微生物进行生物修复已被广泛用于治理自然环境中的重金属污染，微生物与作物之间的相互作用对于缓解重金属胁迫至关重要。在此，我们在[具体微生物名称]的外膜中表达与两个金属结合结构域（PbBD和MTT5）融合的Lpp-OmpA，以增强对Cd和Pb的吸附。我们的结果表明，重组菌株LOPM对Cd和Pb胁迫的耐受性增强，与野生型菌株R1相比，其对Cd的吸附能力提高了4.9倍，对Pb的吸附能力提高了3.2倍。在LOPM细胞定殖于水稻根际后，与植株暴露于Cd和Pb的情况相比，根部Cd含量降低至47.0%，地上部降低至43.4%；根部Pb含量降低至55.4%，地上部降低至26.9%。此外，定殖在水稻根上的LOPM菌株细胞通过降低水稻中的活性氧水平和增强抗氧化酶活性，减轻了Cd和Pb诱导的氧化胁迫。本研究为基因工程嗜极细菌在减少水稻中重金属积累和毒性方面提供了一个有前景的应用。
