A unique program for cell death in xylem fibers of Populus stem
A unique program for cell death in xylem fibers of Populus stem
复制标题
DOI：
10.1111/j.1365-313x.2008.03777.x
复制
发表时间：
2009-04-01
期刊：
影响因子：
7.2
通讯作者：
Tuominen, Hannele
中科院分区：
文献类型：
--
作者：
Courtois-Moreau, Charleen L.;Pesquet, Edouard;Tuominen, Hannele
木质部分子的成熟包括次生细胞壁物质的大量沉积和导致细胞死亡的自溶过程。我们在这里描述了一个独特的类型的细胞死亡程序在木质部纤维的杂交白杨（杨tremula × P. tremuloides）茎，包括在细胞核和细胞质中的逐渐降解过程，同时与活跃的细胞壁沉积的阶段。细胞核DNA的完整性，通过TUNEL（末端脱氧核苷酸转移酶介导的dUTP缺口末端标记）和彗星（单细胞凝胶电泳）测定，在纤维成熟的早期受到损害。此外，通过高压冷冻/冷冻置换（HPF-FS）固定的样品的电子显微镜检测到细胞质内容物的降解是逐渐的，并导致在液泡完整性丧失之前完全丧失细胞质内容物，这被认为是死亡的时刻。这种类型的细胞死亡与木质部导管中所见的细胞死亡显著不同。液泡完整性的丧失被认为是木质部导管中细胞降解过程的开始，是木质部纤维中剩余细胞内容物最终自溶之前发生的最后过程之一。高分辨率的微阵列分析在杨树茎的维管组织中，结合公开的数据库的计算机分析，表明参与了几个以前未表征的转录因子，乙烯，鞘脂和光信号，以及自噬纤维细胞死亡的控制。
Maturation of the xylem elements involves extensive deposition of secondary cell-wall material and autolytic processes resulting in cell death. We describe here a unique type of cell-death program in xylem fibers of hybrid aspen (Populus tremula x P. tremuloides) stems, including gradual degradative processes in both the nucleus and cytoplasm concurrently with the phase of active cell-wall deposition. Nuclear DNA integrity, as determined by TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) and Comet (single-cell gel electrophoresis) assays, was compromised early during fiber maturation. In addition, degradation of the cytoplasmic contents, as detected by electron microscopy of samples fixed by high-pressure freezing/freeze substitution (HPF-FS), was gradual and resulted in complete loss of the cytoplasmic contents well before the loss of vacuolar integrity, which is considered to be the moment of death. This type of cell death differs significantly from that seen in xylem vessels. The loss of vacuolar integrity, which is thought to initiate cell degradative processes in the xylem vessels, is one of the last processes to occur before the final autolysis of the remaining cell contents in xylem fibers. High-resolution microarray analysis in the vascular tissues of Populus stem, combined with in silico analysis of publicly available data repositories, suggests the involvement of several previously uncharacterized transcription factors, ethylene, sphingolipids and light signaling as well as autophagy in the control of fiber cell death.