Characterization of tobacco MADS-box genes involved in floral initiation
Characterization of tobacco MADS-box genes involved in floral initiation
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DOI：
10.1093/pcp/pcf015
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发表时间：
2002-02-01
影响因子：
4.9
通讯作者：
An, GH
中科院分区：
文献类型：
--
作者：
Jang, SH;An, K;An, GH
MADS盒基因编码的调控因子参与植物发育的各个阶段。这些基因的功能不仅在早期的花分生组织的身份，而且当花器官原基的命运是在以后的步骤中确定。在这里，我们筛选的花蕾cDNA文库中分离烟草MADS-box基因，NtMADS 4，使用水稻MADS-box基因，OsMADS 1，作为探针。我们以前报道过OsMADS 1在水稻花发育中起着关键作用。NtMADS 4的异位表达导致极早开花和矮化的表型。植物MADS蛋白具有介导二聚体形成的K结构域。这种二聚化似乎是功能性蛋白质复合物的必要步骤。通过酵母双杂交筛选，NtMADS 11作为NtMADS 4的相互作用配偶体被分离。后者被包括在AGAMOUS样2（AGL 2）家族中，而前者被分类在SQUAMOSA（SQUA）家族中。NtMADS 4的转录本仅在生殖器官中检测到，而NtMADS 11的转录本在生殖器官和营养器官中都可以检测到。在早期发育阶段，这两个基因的表达水平都很高。NtMADS 1 - 1和OsMADS 14的异位表达能够挽救在强ap 1 -1突变体中看到的花器官缺陷。讨论了NtMADS 4和NtMADS 11在花发育中的作用。
MADS-box genes encode regulatory factors that are involved at various stages in plant development. These genes function not only during early floral meristem identity, but also when the fate of floral organ primordia is determined in a later step. Here, we screened a floral bud cDNA library to isolate a tobacco MADS-box gene, NtMADS4, using the rice MADS-box gene, OsMADS1, as a probe. We previously reported that OsMADS1 plays a critical role in flower development in rice. Ectopic expression of NtMADS4 caused phenotypes of extremely early flowering as well as dwarfism. Plant MADS proteins have a K domain that mediates the formation of dimers. This dimerization appears to be an essential step for a functional protein complex. NtMADS11 was isolated as an interacting partner of NtMADS4 by yeast two-hybrid screening. The latter was included in the AGAMOUS-like 2 (AGL2) family whereas the former was categorized in the SQUAMOSA (SQUA) family. While the transcript of NtMADS4 was detectable only in reproductive organs, that of NtMADS11 was seen in both reproductive and vegetative organs. Expression levels were high for both genes during early developmental stages. Ectopic expression of NtMADS11 and OsMADS14 was able to rescue the floral organ defects seen in the strong ap1-1 mutant. Roles of NtMADS4 and NtMADS11 in the floral initiation are discussed.