Induction of cdc2a and cyc1At expression in Arabidopsis thaliana during early phases of nematode-induced feeding cell formation
Induction of cdc2a and cyc1At expression in Arabidopsis thaliana during early phases of nematode-induced feeding cell formation
复制标题
DOI：
10.1046/j.1365-313x.1996.10061037.x
复制
发表时间：
1996-12-01
期刊：
影响因子：
7.2
通讯作者：
Gheysen, G
中科院分区：
文献类型：
--
作者：
Niebel, A;Engler, JD;Gheysen, G
根结线虫和胞囊线虫是植物寄生虫，可在宿主的根部诱导产生大型多核摄食细胞。细胞学观察表明，根结线虫通过有丝分裂周期诱导巨细胞而不进行胞质分裂，而胞囊线虫则引起细胞壁降解，从而形成大合胞体。本研究旨在表征和比较两种线虫诱导细胞周期进展的能力。为此，在线虫感染后，跟踪了两种细胞周期标记的表达：分裂能力标记，细胞周期蛋白依赖性激酶 cdc2a 和 G2 期标记，有丝分裂细胞周期蛋白 cyc1At。对于两种类型的线虫，这些标记的转录激活与摄食细胞发育的早期阶段相关。因此，使用分子标记，可以确认和扩展根结线虫诱导巨细胞中重复有丝分裂的观察。令人惊讶的是，在胞囊线虫感染时，在尚未明确报道有丝分裂的摄食细胞中，也发现了 cdc2a 和 cyc1At 标记的启动子激活。这些合胞体中掺入氚化胸苷证实了它们正在经历细胞周期的 S 期。一种可能性是胞囊线虫诱导 DNA 内复制周期分流 M 期。尽管个体发育存在明显差异，但共同的分子机制，包括 DNA 核内复制和 cdc2a 和 cyc1At 表达的循环，可能参与巨细胞或合胞体的形成。
Root-knot and cyst nematodes are plant parasites that induce large multinucleated feeding cells in the roots of their hosts. Cytological observations have shown that root-knot nematodes induce giant cells by cycles of mitosis without cytokinesis whereas cyst nematodes provoke cell wall degradation leading to the formation of a large syncytium. This study was intended to characterize and compare the ability of both types of nematodes to induce progression through the cell cycle. For this purpose, the expression, upon nematode infection, of two cell cycle markers was followed: a marker for division competence, the cyclin-dependent kinase cdc2a and a marker for the G2 phase, the mitotic cyclin cyc1At. For both types of nematodes, transcriptional activation of these markers was correlated with early phases of feeding cell development. Using molecular markers, it was thus possible to confirm and extend the observations of repeated mitosis in root-knot nematode induced giant cells. Surprisingly, promoter activation of both cdc2a and cyc1At markers was also found upon cyst nematode infection, in feeding cells in which mitosis has not been clearly reported. Incorporation of tritiated thymidine in these syncytia confirms that they progress through the S phase of the cell cycle. One possibility is that cyst nematodes induce cycles of DNA endoreduplication shunting the M phase. Despite obvious differences in ontogeny, common Molecular mechanisms, involving cycles of DNA endoreduplication and cdc2a and cyc1At expression, might thus be involved in the formation of a giant cell or a syncytium.