Swid Neora, Nevo Reinat, Kiss Vladimir, Kapon Ruti, Dagan Shlomi, Snir Orli, Adam Zach, Falconet Denis, Reich Ziv, Charuvi Dana
The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Hebrew University of Jerusalem, Rehovot 7610001, Israel; Institute of Plant Sciences, Agricultural Research Organization - Volcani Center, Rishon LeZion 7505101, Israel; Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel.
Dev Biol. 2018 Sep 1;441(1):83-94. doi: 10.1016/j.ydbio.2018.06.010. Epub 2018 Jun 18.
FtsZ proteins of the FtsZ1 and FtsZ2 families play important roles in the initiation and progression of plastid division in plants and green algae. Arabidopsis possesses a single FTSZ1 member and two FTSZ2 members, FTSZ2-1 and FTSZ2-2. The contribution of these to chloroplast division and partitioning has been mostly investigated in leaf mesophyll tissues. Here, we assessed the involvement of the three FtsZs in plastid division at earlier stages of chloroplast differentiation. To this end, we studied the effect of the absence of specific FtsZ proteins on plastids in the vegetative shoot apex, where the proplastid-to-chloroplast transition takes place. We found that the relative contribution of the two major leaf FtsZ isoforms, FtsZ1 and FtsZ2-1, to the division process varies with cell lineage and position within the shoot apex. While FtsZ2-1 dominates division in the L1 and L3 layers of the shoot apical meristem (SAM), in the L2 layer, FtsZ1 and FtsZ2-1 contribute equally toward the process. Depletion of the third isoform, FtsZ2-2, generally resulted in stronger effects in the shoot apex than those observed in mature leaves. The implications of these findings, along with additional observations made in this work, to our understanding of the mechanisms and regulation of plastid proliferation in the shoot apex are discussed.
FtsZ1和FtsZ2家族的FtsZ蛋白在植物和绿藻的质体分裂起始和进程中发挥重要作用。拟南芥有一个FTSZ1成员和两个FTSZ2成员，即FTSZ2-1和FTSZ2-2。这些蛋白对叶绿体分裂和分配的作用大多是在叶片叶肉组织中进行研究的。在此，我们评估了这三种FtsZ蛋白在叶绿体分化早期阶段对质体分裂的参与情况。为此，我们研究了缺失特定FtsZ蛋白对营养茎尖质体的影响，质体到叶绿体的转变就在茎尖发生。我们发现，两种主要的叶片FtsZ异构体FtsZ1和FtsZ2-1对分裂过程的相对贡献随细胞谱系和茎尖内的位置而变化。虽然FtsZ2-1在茎尖分生组织（SAM）的L1和L3层中主导分裂，但在L2层中，FtsZ1和FtsZ2-1对这一过程的贡献相同。第三种异构体FtsZ2-2的缺失通常在茎尖产生比在成熟叶片中观察到的更强的影响。本文还讨论了这些发现以及在这项工作中所做的其他观察结果对我们理解茎尖质体增殖机制和调控的意义。
