橡胶蒲公英 （Taraxacum kok-saghyz） 中 MYB 相关转录因子家族：对乳胶为主成员 TkMYBR090 的见解
International Journal of Biological Macromolecules ( IF 7.7 ) Pub Date : 2025-02-18 , DOI: 10.1016/j.ijbiomac.2025.141058
Yongmei Li 1 , Zhonghua Li 2 , Tiancheng Xu 1 , Xue Yang 2 , Yuying Zhang 1 , Jiyan Qi 2 , Jiang Wang 2 , Qingbiao Xie 2 , Kaiye Liu 2 , Chaorong Tang 2
Affiliation
Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, China; School of Tropical Agriculture and Forestry, Hainan University, Danzhou, /Sanya, China.
Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, China; School of Tropical Agriculture and Forestry, Hainan University, Danzhou, /Sanya, China; Natural Rubber Cooperative Innovation Center of Hainan Province & Ministry of Education of PRC, Haikou, China.
MYB 相关 （MYBR） 蛋白在植物生长发育中发挥着多种作用。然而，Taraxacum kok-saghyz 中的 MYBR 基因是一种很有前途的天然橡胶替代来源，是一种有价值的生物聚合物，仍然很少被研究。在这里，共鉴定出 122 个 MYBR 基因，即 TkMYBRs，并将其分为 GARP 样、CCA1 样/R-R 和异质性 T. kok-saghyz 组。共线性分析显示，两种蒲公英物种的 MYBRs 高度相似，橡胶产量截然不同。TkMYBR090 在乳胶中表现出主要表达，乳胶是产橡胶乳胶的细胞质。TkMYBR090 在烟草和 T. kok-saghyz 中的瞬时过表达证明了其定位于细胞核和细胞质中。酵母双杂交试验显示 TkMYBR090 的 C 端具有转录激活活性。DAP-seq 分析鉴定了 18,232 个 TkMYBR090 靶向候选基因，以及 4 个显著富集的 TkMYBR090 DNA 结合启动子基序，这些基序已通过酵母单杂交测定验证。通过酵母单杂交和双荧光素酶活性测定验证了 TkMYBR090 与抗坏血酸氧化酶基因启动子的结合，表明在 ROS 代谢中发挥作用。烟草和酵母中 TkMYBR090 的异源表达测定支持了这一假设。本研究有利于进一步对 T. kok-saghyz 中 MYBRs 进行功能解剖，特别是其在产橡胶乳胶的发育和功能中的作用。
The MYB-related transcription factor family in rubber dandelion (Taraxacum kok-saghyz): An insight into a latex-predominant member, TkMYBR090
MYB-related (MYBR) proteins play diverse roles in plant growth and development. However, the MYBR genes in Taraxacum kok-saghyz, a promising alternative source of natural rubber, a valuable biopolymer, remain scarcely investigated. Here, a total of 122 MYBR genes, namely TkMYBRs, were identified and classified into the groups of GARP-like, CCA1-like/R-R, and a heterogenous one in T. kok-saghyz. Collinearity analysis revealed a high similarity in MYBRs across two Taraxacum species with contrasting rubber yield. TkMYBR090 showed predominant expression in latex, the cytoplasm of rubber-producing laticifers. Transient overexpression of TkMYBR090 in tobacco and T. kok-saghyz demonstrated its localizations in nucleus and cytoplasm. Yeast two-hybrid assay revealed that the C-terminus of TkMYBR090 possessed transcriptional activation activity. DAP-seq analysis identified 18,232 TkMYBR090-targeted candidate genes, and four significantly enriched TkMYBR090 DNA-binding promoter motifs that were validated by yeast one-hybrid assay. The binding of TkMYBR090 on the promoter of an ascorbate oxidase gene was verified by yeast one-hybrid and dual luciferase activity assays, suggesting a role in ROS metabolism. Such assumption was supported by heterologous expression assays of TkMYBR090 in tobacco and yeast. This study is beneficial to further functional dissection of MYBRs in T. kok-saghyz, especially the roles in development and function of rubber-producing laticifers.
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