A mechanism coordinating root elongation, endodermal differentiation, redox homeostasis and stress response
A mechanism coordinating root elongation, endodermal differentiation, redox homeostasis and stress response
复制标题
协调根伸长、内胚层分化、氧化还原稳态和应激反应的机制
DOI：
10.1111/tpj.15361
复制
发表时间：
2021-06-18
期刊：
影响因子：
7.2
通讯作者：
Cui, Hongchang
中科院分区：
文献类型：
--
作者：
Fu, Jing;Zhang, Xinglin;Cui, Hongchang
根的生长依赖于细胞分裂和细胞伸长，它们分别发生在分生组织和伸长区。SCARECROW（SCR）和SHORT-ROOT（SHR）是拟南芥根生长和辐射状形成所必需的GRAS家族基因。先前的研究表明，SCR和SHR通过抑制分生组织中的细胞分裂素反应来促进根的生长，但有证据表明，在分生组织之外表达的SCR也是根生长所必需的。在这里，我们报告了一个以前未知的SCR在促进细胞伸长的作用。与此相一致，我们发现，scr突变体积累了更高水平的活性氧（ROS）在延伸区，这可能是由于过氧化物酶基因3，消耗过氧化氢的反应，导致凯氏带形成的表达减少。当氧化应激反应被阻断在scr突变体突变脱落酸2（ABA 2）或氧化还原状态改善的乐观1（upb 1）突变体时，根变得显着更长，更长的细胞和更大，更有丝分裂活性的分生组织。然而，值得注意的是，双突变体中的干细胞和放射状图案缺陷仍然存在。由于活性氧和过氧化物酶是必不可少的内胚层分化，这些结果表明，SCR起着协调细胞伸长，内胚层分化，氧化还原稳态和氧化应激反应在根中的作用。我们还提供了证据表明，SCR的这种作用是独立的SHR，即使它们在根生长和发育的其他方面的功能相似。
Root growth relies on both cell division and cell elongation, which occur in the meristem and elongation zones, respectively. SCARECROW (SCR) and SHORT-ROOT (SHR) are GRAS family genes essential for root growth and radial patterning in the Arabidopsis root. Previous studies showed that SCR and SHR promote root growth by suppressing cytokinin response in the meristem, but there is evidence that SCR expressed beyond the meristem is also required for root growth. Here we report a previously unknown role for SCR in promoting cell elongation. Consistent with this, we found that the scr mutant accumulated a higher level of reactive oxygen species (ROS) in the elongation zone, which is probably due to decreased expression of peroxidase gene 3, which consumes hydrogen peroxide in a reaction leading to Casparian strip formation. When the oxidative stress response was blocked in the scr mutant by mutation in ABSCISIC ACID 2 (ABA2) or when the redox status was ameliorated by the upbeat 1 (upb1) mutant, the root became significantly longer, with longer cells and a larger and more mitotically active meristem. Remarkably, however, the stem cell and radial patterning defects in the double mutants still persisted. Since ROS and peroxidases are essential for endodermal differentiation, these results suggest that SCR plays a role in coordinating cell elongation, endodermal differentiation, redox homeostasis and oxidative stress response in the root. We also provide evidence that this role of SCR is independent of SHR, even though they function similarly in other aspects of root growth and development.