Liu Huabin, Wu Yue, Cai Jiahui, Chen Yuting, Zhou Cheng, Qiao Cece, Wang Yuliang, Wang Song
College of Life and Health Sciences, Anhui Science and Technology University, Chuzhou 233100, China.
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Toxics. 2024 May 19;12(5):374. doi: 10.3390/toxics12050374.
Auxins play crucial regulatory roles in plants coping with cadmium (Cd) stress. However, the regulatory mechanism by which auxins alleviate Cd toxicity in tomato seedlings remains unclear. Here, we demonstrate that exposure to Cd stress leads to dynamic changes in the auxin response in tomato roots, characterized by an initial increase followed by a subsequent weakening. Under Cd stress, tomato seedlings show primary root- and hypocotyl-growth inhibition, accompanied by the accumulation of Cd and reactive oxygen species (ROS) in the roots. The exogenous application of 1-naphthylacetic acid (NAA) does not mitigate the inhibitory effect of Cd toxicity on primary root growth, but it does significantly enhance lateral root development under Cd stress. Auxin transport inhibitors, such as 1-N-naphthylphthalamic acid (NPA) and 2,3,5-triiodobenoic acid (TIBA), aggravate the growth inhibition of primary roots caused by Cd stress. Additionally, lateral root development was inhibited by NPA. However, applying auxin synthesis inhibitors L-kynurenine (kyn) and yucasin alleviated the tomato root growth inhibition caused by Cd stress; between them, the effect of yucasin was more pronounced. Yucasin mitigates Cd toxicity in tomato seedlings by reducing Cd absorption and auxin accumulation, strengthening ROS scavenging, and reducing cell death in roots. These observations suggest that yucasin potentially mitigates Cd toxicity and improves the tolerance of tomato seedlings to Cd stress.
生长素在植物应对镉（Cd）胁迫过程中发挥着关键的调节作用。然而，生长素缓解番茄幼苗镉毒性的调节机制仍不清楚。在此，我们证明，暴露于镉胁迫会导致番茄根中生长素反应的动态变化，其特征是先增加后减弱。在镉胁迫下，番茄幼苗表现出主根和下胚轴生长受抑制，同时根中镉和活性氧（ROS）积累。外源施加1-萘乙酸（NAA）并不能减轻镉毒性对主根生长的抑制作用，但它确实能显著促进镉胁迫下侧根的发育。生长素运输抑制剂，如1-N-萘基邻氨甲酰苯甲酸（NPA）和2,3,5-三碘苯甲酸（TIBA），会加剧镉胁迫对主根生长的抑制。此外，NPA抑制侧根发育。然而，施加生长素合成抑制剂L-犬尿氨酸（kyn）和玉蜀黍素可缓解镉胁迫对番茄根生长的抑制；其中，玉蜀黍素的效果更明显。玉蜀黍素通过减少镉吸收和生长素积累、增强ROS清除以及减少根细胞死亡来减轻番茄幼苗的镉毒性。这些观察结果表明，玉蜀黍素可能减轻镉毒性并提高番茄幼苗对镉胁迫的耐受性。
