镉(Cd)是环境中一种重要的重金属污染物,具有显著的毒性水平,对植物和人类都有很大的危害。胡萝卜(Daucuscarota),全球重要的块根蔬菜作物,已经进化出多种转录调控机制来应对Cd胁迫,与成髓细胞病(MYB)转录因子的关键参与。在这项研究中,DcMYB62基因编码288个氨基酸,定位于细胞核中,并表现出转录激活特性,是从胡萝卜中分离出来的(简历。\'黑田\')。在两个不同的胡萝卜品种中,DcMYB62的表达水平与类胡萝卜素的积累模式之间存在正相关关系。进一步研究表明,DcMYB62的表达通过提高拟南芥种子的发芽率来提高拟南芥对Cd的耐受性,根长,和总生存率。DcMYB62转基因拟南芥中的类胡萝卜素水平超过野生型,伴随着15-顺式八烯去饱和酶的表达水平升高,ζ-胡萝卜素去饱和酶,和类胡萝卜素异构酶。同时,DcMYB62的异源表达促进了脱落酸(ABA)和硫化氢(H2S)的生物合成,这反过来又抑制了过氧化氢和超氧阴离子的形成,同时也刺激气孔关闭。此外,DcMYB62的异源表达增加了拟南芥重金属抗性相关基因的转录,特别是烟胺合成酶。总的来说,这项研究有助于了解DcMYB62如何通过调节类胡萝卜素的生物合成途径来促进植物对Cd胁迫的抗性,ABA,H2S,这为DcMYBs与胡萝卜Cd胁迫反应的调控机制提供了有价值的见解。
Cadmium (Cd) is a significant heavy metal contaminant within the environment, carrying a notable level of toxicity that presents a substantial hazard to both plant and human. Carrot (Daucus carota), a significant root vegetable crop globally, have evolved multiple transcriptional regulatory mechanisms to cope with Cd stress, with a crucial involvement of the myeloblastosis (MYB) transcription factor. In this study, the DcMYB62 gene encoding 288 amino acids, localized in the nucleus and demonstrated transcription activation property, was isolated from carrot (cv. \'Kuroda\'). There was a positive relationship observed between the levels of DcMYB62 expression and the accumulation patterns of carotenoids in two distinct carrot cultivars. Further investigation revealed that the expression of DcMYB62 improved Cd tolerance of Arabidopsis by increasing seed germination rate, root length, and overall survival rate. The levels of carotenoids in DcMYB62 transgenic Arabidopsis surpassed those in wild type, accompanied by elevated expression levels of 15-cis-phytoene desaturase, zeta-carotene desaturase, and carotenoid isomerase. Meanwhile, the heterologous expression of DcMYB62 promoted the biosynthesis of abscisic acid (ABA) and hydrogen sulfide (H2S), which in turn suppressed the formation of hydrogen peroxide and superoxide anion, while also stimulating stomatal closure. Furthermore, the heterologous expression of DcMYB62 increased the transcription of genes associated with heavy metal resistance in Arabidopsis, notably nicotianamine synthase. Overall, this study contributes to understanding how DcMYB62 promote Cd stress resistance of plants by regulating the biosynthesis pathways of carotenoids, ABA, and H2S, which offers valuable insights into the regulatory mechanism connecting DcMYBs with Cd stress response of carrot.