Salvi Elena, Di Mambro Riccardo, Pacifici Elena, Dello Ioio Raffaele, Costantino Paolo, Moubayidin Laila, Sabatini Sabrina
a Dipartimento di Biologia e Biotecnologie , Università di Roma La Sapienza , Rome , Italy.
b Dipartimento di Biologia , Università di Pisa , Pisa , Italy.
Plant Signal Behav. 2018;13(8):e1507402. doi: 10.1080/15592324.2018.1507402. Epub 2018 Aug 20.
The root apical meristem is established during embryogenesis, when its organizer, the quiescent center, is specified and the stem cell niche is positioned. The SCARECROW-SHORTROOT heterodimer is essential for quiescent center specification and maintenance. As continuous post-embryonic root growth relies upon the SCARECROW-mediated control of the cytokinin/auxin balance, we investigated the role of SCARECROW and SHORTROOT in controlling cytokinin signaling during embryonic quiescent center specification. We found that from embryogenesis onward both SCARECROW and SHORTROOT antagonize cytokinin signaling, thus repressing the expression of the auxin biosynthetic enzyme ANTRANILATHE SYNTHASE BETA 1. This mechanism prevents detrimental and premature high auxin levels in the QC allowing the establishment of a functional embryonic root pole.
根顶端分生组织在胚胎发育过程中形成，此时其组织者静止中心被确定，干细胞龛也已定位。稻草人-短根异源二聚体对于静止中心的确定和维持至关重要。由于胚胎后根的持续生长依赖于稻草人介导的细胞分裂素/生长素平衡控制，我们研究了稻草人（SCARECROW）和短根（SHORTROOT）在胚胎静止中心形成过程中控制细胞分裂素信号传导的作用。我们发现，从胚胎发育开始，稻草人（SCARECROW）和短根（SHORTROOT）都拮抗细胞分裂素信号传导，从而抑制生长素生物合成酶β-腈基色氨酸合成酶1（ANTRANILATHE SYNTHASE BETA 1）的表达。这种机制可防止静止中心出现有害且过早的高生长素水平，从而使功能性胚胎根极得以形成。
