NAC Family Proteins NARS1/NAC2 and NARS2/NAM in the Outer Integument Regulate Embryogenesis in Arabidopsis
NAC Family Proteins NARS1/NAC2 and NARS2/NAM in the Outer Integument Regulate Embryogenesis in Arabidopsis
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DOI：
10.1105/tpc.108.060160
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发表时间：
2008-10-01
期刊：
影响因子：
11.6
通讯作者：
Hara-Nishimura, Ikuko
中科院分区：
文献类型：
--
作者：
Kunieda, Tadashi;Mitsuda, Nobutaka;Hara-Nishimura, Ikuko
种子形态发生包括胚胎发生和母体组织的发育，如内珠被和外珠被，两者都产生种皮。我们表明，表达嵌合阻遏物来自NAC调节种子形态1和-2（NARS 1和NARS 2，也被称为NAC 2和NAM，分别）引起异常的种子形状在拟南芥。双敲除突变体nars 1 nars 2表现出异常形状的种子，而且，nars 1和nars 2都没有产生异常的种子，表明NARS 1和NARS 2冗余调节种子形态建成。退化的珠被nars 1 nars 2显着延迟，而野生型发生在鱼雷形胚胎阶段。此外，nars 1 nars 2在胚胎发生中表现出缺陷：一些nars 1 nars 2胚胎在鱼雷形胚胎阶段发育受阻。然而，出乎意料的是，NARS 1和NARS 2在这个阶段的胚胎中都不表达，尽管它们被发现在外珠被中表达。野生型雌蕊授粉nars 1 nars 2花粉产生正常的种子，而反向杂交产生异常的种子。总而言之，这些结果表明NARS 1和NARS 2通过调节胚珠珠被的发育和退化来调节胚胎发生。我们的研究结果表明，胚胎和母体珠被之间存在组织间的通讯。
Seed morphogenesis consists of embryogenesis and the development of maternal tissues such as the inner and outer integuments, both of which give rise to seed coats. We show that expression of chimeric repressors derived from NAC-REGULATED SEED MORPHOLOGY1 and -2 (NARS1 and NARS2, also known as NAC2 and NAM, respectively) caused aberrant seed shapes in Arabidopsis thaliana. Double knockout mutant nars1 nars2 exhibited abnormally shaped seeds; moreover, neither nars1 nor nars2 produced abnormal seeds, indicating that NARS1 and NARS2 redundantly regulate seed morphogenesis. Degeneration of the integuments in nars1 nars2 was markedly delayed, while that of the wild type occurred around the torpedo-shaped embryo stage. Additionally, nars1 nars2 showed a defect in embryogenesis: some nars1 nars2 embryos were developmentally arrested at the torpedo-shaped embryo stage. Unexpectedly, however, neither NARS1 nor NARS2 was expressed in the embryo at this stage, although they were found to be expressed in the outer integument. Wild-type pistils pollinated with nars1 nars2 pollen generated normal seeds, while the reverse crossing generated abnormal seeds. Taken together, these results indicate that NARS1 and NARS2 regulate embryogenesis by regulating the development and degeneration of ovule integuments. Our findings suggest that there is an intertissue communication between the embryo and the maternal integument.