Physiological, transcriptomic, and metabolomic analyses uncover crucial factors enhancing cadmium stress tolerance in centipedegrass

This study analyzed the physiological, transcriptomic, and metabolomic changes in centipedegrass to elucidate the pivotal mechanisms involved in Cd tolerance. Centipedegrass exhibited a heightened capacity for Cd absorption and transportation. Moderate Cd concentrations had no significant impact on plant growth, whereas elevated Cd concentrations inhibited growth. Higher Cd levels led to decreased photosynthetic efficiency, elevated lignin, abscisic acid (ABA), and salicylic acid (SA) contents, increased activity of antioxidant enzymes, and malondialdehyde (MDA) levels. The integrated analysis of the transcriptome and metabolome revealed the potential critical roles of phenylpropanoid biosynthesis, plant hormones, and ABC transporters in Cd detoxification in centipedegrass. Overexpression of the metal transporter ATP−binding cassette B11 (EoABCB11) in Arabidopsis conferred high Cd tolerance. These findings indicate that centipedegrass possesses robust resistance and transport capabilities against Cd toxicity, potentially attributed to ABA−, SA−, and lignin−mediated positive defense responses, primarily involving enhanced antioxidant enzyme activity and cell wall reinforcement. These pots were filled with red soil containing varying cadmium concentrations: 0 (CK), 50 (Cd50), 100 (Cd100), and 200 mg kg−1 (Cd200) (CdCl2).

本研究以假俭草（centipedegrass）为材料，分析其在镉（Cd）胁迫下的生理、转录组及代谢组变化，以阐明其镉耐受的关键调控机制。假俭草展现出更强的镉吸收与转运能力。中等浓度的镉对植株生长无显著影响，而高浓度镉则会抑制植株生长。高浓度镉会降低光合效率，提升木质素、脱落酸（ABA）与水杨酸（SA）含量，增强抗氧化酶活性，并提高丙二醛（MDA）水平。对转录组与代谢组的整合分析显示，苯丙烷类生物合成、植物激素信号通路及ABC转运蛋白在假俭草的镉解毒过程中发挥潜在关键作用。在拟南芥中过表达金属转运蛋白ATP结合盒B11（EoABCB11）可使其获得极强的镉耐受能力。上述研究结果表明，假俭草对镉毒性具备优异的抗性与转运能力，这一特性可能源于脱落酸（ABA）、水杨酸（SA）及木质素介导的正向防御响应，主要包括增强抗氧化酶活性与强化细胞壁结构。本实验所用花盆均装填含有不同浓度镉的红壤，镉浓度分别为0（对照组CK）、50、100及200 mg·kg⁻¹，对应分组为Cd50、Cd100与Cd200，镉源为氯化镉（CdCl₂）。