Jing Tingting, Ardiansyah Rhomi, Xu Qijiang, Xing Qian, Müller-Xing Ralf
Key Laboratory of Saline-Alkali Vegetation Ecology Restoration (Northeast Forestry University), Ministry of Education, Harbin, China.
Institute of Development, College of Life Science, Northeast Forestry University, Harbin, China.
Front Plant Sci. 2020 Mar 25;11:317. doi: 10.3389/fpls.2020.00317. eCollection 2020.
Many plant species are able to regenerate adventitious roots either directly from aerial organs such as leaves or stems, in particularly after detachment (cutting), or indirectly, from over-proliferating tissue termed callus. In agriculture, this capacity of root formation from cuttings can be used to clonally propagate several important crop plants including cassava, potato, sugar cane, banana and various fruit or timber trees. Direct and indirect root regeneration (DNRR) originates from pluripotent cells of the pericycle tissue, from other root-competent cells or from non-root-competent cells that first dedifferentiate. Independently of their origin, the cells convert into root founder cells, which go through proliferation and differentiation subsequently forming functional root meristems, root primordia and the complete root. Recent studies in the model plants and rice have identified several key regulators building in response to the phytohormone auxin transcriptional networks that are involved in both callus formation and DNRR. In both cases, epigenetic regulation seems essential for the dynamic reprogramming of cell fate, which is correlated with local and global changes of the chromatin states that might ensure the correct spatiotemporal expression pattern of the key regulators. Future approaches might investigate in greater detail whether and how the transcriptional key regulators and the writers, erasers, and readers of epigenetic modifications interact to control DNRR.
许多植物物种能够直接从叶片或茎等地上器官再生不定根，尤其是在脱离（切割）后，或者间接从过度增殖的愈伤组织再生不定根。在农业中，这种从插条形成根的能力可用于克隆繁殖几种重要的作物，包括木薯、马铃薯、甘蔗、香蕉以及各种果树或用材树。直接和间接根再生（DNRR）起源于中柱鞘组织的多能细胞、其他具有生根能力的细胞或首先去分化的无生根能力的细胞。无论其起源如何，这些细胞都会转化为根原基细胞，根原基细胞经过增殖和分化，随后形成功能性根分生组织、根原基和完整的根。最近在模式植物拟南芥和水稻中的研究已经确定了几个关键调控因子，它们构建了响应植物激素生长素的转录网络，这些网络参与愈伤组织形成和DNRR。在这两种情况下，表观遗传调控似乎对于细胞命运的动态重编程至关重要，这与染色质状态的局部和全局变化相关，这些变化可能确保关键调控因子的正确时空表达模式。未来的研究可能会更详细地研究转录关键调控因子以及表观遗传修饰的写入者、擦除者和读取者是否以及如何相互作用来控制DNRR。
