Sequential steps for developmental arrest in Arabidopsis seeds.
Sequential steps for developmental arrest in Arabidopsis seeds.
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发表时间：
2001-01
期刊：
影响因子：
4.6
通讯作者：
V. Raz;J. Bergervoet;M. Koornneef
中科院分区：
文献类型：
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作者：
V. Raz;J. Bergervoet;M. Koornneef
在种子成熟过程中，植物胚胎的持续生长被中断，导致种子休眠。胚胎在萌发后继续发育，长成幼苗。胚的生长阶段在形态发生后开始，在胚填满种囊时结束。我们对调控这一阶段的过程所知甚少。我们描述了在两个连续的发育阶段影响胚胎生长的突变体。首先，胚胎生长停滞是由FUS3/LEC型基因调控的，因为这些基因的突变会导致未成熟胚胎的生长继续。其次，胚胎后期休眠受ABI3和脱落酸的调控；ab3和aba1突变体只有在胚胎成熟后才表现出早熟。影响两个发育阶段的突变导致加性表型，双突变是高度胎生的。胚胎生长停滞受胚胎和胚乳细胞分裂活动的调控，胚乳和胚胎细胞分裂活动在胚胎成熟阶段逐渐关闭。然而，在fus3/lec突变体中，胚胎和胚乳中的细胞分裂并没有被阻止，而是在种子成熟过程中被延长。此外，异位细胞分裂发生在幼苗中。我们的研究结果表明，种子休眠是通过至少两个连续的发育过程来保证的：胚胎生长停滞，这是由细胞分裂和胚胎休眠调节的。
The continuous growth of the plant embryo is interrupted during the seed maturation processes which results in a dormant seed. The embryo continues development after germination when it grows into a seedling. The embryo growth phase starts after morphogenesis and ends when the embryo fills the seed sac. Very little is known about the processes regulating this phase. We describe mutants that affect embryo growth in two sequential developmental stages. Firstly, embryo growth arrest is regulated by the FUS3/LEC type genes, as mutations in these genes cause a continuation of growth in immature embryos. Secondly, a later stage of embryo dormancy is regulated by ABI3 and abscisic acid; abi3 and aba1 mutants exhibit premature germination only after embryos mature. Mutations affecting both developmental stages result in an additive phenotype and double mutants are highly viviparous. Embryo growth arrest is regulated by cell division activities in both the embryo and the endosperm, which are gradually switched off at the mature embryo stage. In the fus3/lec mutants, however, cell division in both the embryo and endosperm is not arrested, but rather is prolonged throughout seed maturation. Furthermore ectopic cell division occurs in seedlings. Our results indicate that seed dormancy is secured via at least two sequential developmental processes: embryo growth arrest, which is regulated by cell division and embryo dormancy.