The Arabidopsis mutant feronia disrupts the female gametophytic control of pollen tube reception
The Arabidopsis mutant feronia disrupts the female gametophytic control of pollen tube reception
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DOI：
10.1242/dev.00458
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发表时间：
2003-05-01
期刊：
影响因子：
4.6
通讯作者：
Grossniklaus, U
中科院分区：
文献类型：
--
作者：
Huck, N;Moore, JM;Grossniklaus, U
被子植物的生殖依赖于雄配子体（花粉）与雌花器官（雌蕊、传递组织）和雌配子体（胚囊）的通讯过程。花粉-雌蕊相互作用通过花柱组织控制花粉的水合、萌发和生长。雌配子体参与引导生长中的花粉管向珠孔和胚囊的方向生长。位于卵细胞两侧的两个助细胞中的一个开始退化，并开始接受花粉管进入。花粉管生长停止，花粉管顶端破裂释放出精细胞。助细胞和花粉管之间相互作用的失败必然损害育性。但对花粉管接受的控制还不清楚。我们从拟南芥中分离出一个半不育的雌配子体突变体，以伊特鲁里亚的生育女神命名feronia，这会削弱这一过程。在feronia突变体，胚囊发育和花粉管的指导不受影响，在所有胚珠，虽然一半的胚珠孔突变的雌配子体。然而，当花粉管进入feronia突变体雌配子体的感受性助细胞时，它继续生长，未能破裂释放精细胞，并侵入胚囊。因此，feronia突变破坏了引发这些过程所需的雄性和雌性配子体之间的相互作用。突变体胚囊经常收到多余的花粉管。我们分析了feronia与助细胞特异的GUS标记线，这表明，规格和分化的助细胞是正常的。然而，GUS基因在突变配子体中的表达持续后，花粉管进入，在野生型胚囊，它迅速下降。显然，花粉管接收的失败导致协同特异性基因的持续表达，可能导致潜在的花粉管引诱剂的延长表达。
Reproduction in angiosperms depends on communication processes of the male gametophyte (pollen) with the female floral organs (pistil, transmitting tissue) and the female gametophyte (embryo sac). Pollen-pistil interactions control pollen hydration, germination and growth through the stylar tissue. The female gametophyte is involved in guiding the growing pollen tube towards the micropyle and embryo sac. One of the two synergids flanking the egg cell starts to degenerate and becomes receptive for pollen tube entry. Pollen tube growth arrests and the tip of the pollen tube ruptures to release the sperm cells. Failures in the mutual interaction between the synergid and the pollen tube necessarily impair fertility. But the control of pollen tube reception is not understood. We isolated a semisterile, female gametophytic mutant from Arabidopsis thaliana, named feronia after the Etruscan goddess of fertility, which impairs this process. In the feronia mutant, embryo sac development and pollen tube guidance were unaffected in all ovules, although one half of the ovules bore mutant female gametophytes. However, when the pollen tube entered the receptive synergid of a feronia mutant female gametophyte, it continued to grow, failed to rupture and release the sperm cells, and invaded the embryo sac. Thus, the feronia mutation disrupts the interaction between the male and female gametophyte required to elicit these processes. Frequently, mutant embryo sacs received supernumerary pollen tubes. We analysed feronia with synergid-specific GUS marker lines, which demonstrated that the specification and differentiation of the synergids was normal. However, GUS expression in mutant gametophytes persisted after pollen tube entry, in contrast to wild-type embryo sacs where it rapidly decreased. Apparently, the failure in pollen tube reception results in the continued expression of synergid-specific genes, probably leading to an extended expression of a potential pollen tube attractant.