Kasahara Ryushiro D, Portereiko Michael F, Sandaklie-Nikolova Linda, Rabiger David S, Drews Gary N
Department of Biology, University of Utah, Salt Lake City, Utah 84112-0840, USA.
Plant Cell. 2005 Nov;17(11):2981-92. doi: 10.1105/tpc.105.034603. Epub 2005 Oct 7.
The synergid cells of the female gametophyte play a role in many steps of the angiosperm fertilization process, including guidance of pollen tube growth to the female gametophyte. However, the mechanisms by which the synergid cells become specified and develop their unique features during female gametophyte development are not understood. We identified MYB98 in a screen for Arabidopsis thaliana genes expressed in the female gametophyte. MYB98 is a member of the R2R3-MYB gene family, the members of which likely encode transcription factors. In the context of the ovule, MYB98 is expressed exclusively in the synergid cells, and mutations in this gene affect the female gametophyte specifically. myb98 female gametophytes are affected in two unique features of the synergid cell, pollen tube guidance and the filiform apparatus, but are otherwise normal. MYB98 also is expressed in trichomes and endosperm. Homozygous myb98 mutants exhibit no sporophytic defects, including trichome and endosperm defects. Together, these data suggest that MYB98 controls the development of specific features within the synergid cell during female gametophyte development.
雌配子体的助细胞在被子植物受精过程的多个步骤中发挥作用，包括引导花粉管向雌配子体生长。然而，在雌配子体发育过程中助细胞如何特化并形成其独特特征的机制尚不清楚。我们在筛选拟南芥雌配子体中表达的基因时鉴定出了MYB98。MYB98是R2R3-MYB基因家族的成员，该家族成员可能编码转录因子。在胚珠中，MYB98仅在助细胞中表达，该基因的突变特异性地影响雌配子体。myb98雌配子体在助细胞的两个独特特征——花粉管引导和丝状器方面受到影响，但其他方面正常。MYB98也在毛状体和胚乳中表达。纯合myb98突变体没有表现出孢子体缺陷，包括毛状体和胚乳缺陷。总之，这些数据表明MYB98在雌配子体发育过程中控制着助细胞内特定特征的发育。
