Instituto de Biología Molecular y Celular de Plantas, CSIC-Universidad Politécnica de Valencia, Valencia, Spain.
PLoS One. 2011 Apr 13;6(4):e18760. doi: 10.1371/journal.pone.0018760.
Pistil and fruit morphogenesis is the result of a complex gene network that is not yet fully understood. A search for novel genes is needed to make a more comprehensive model of pistil and fruit development. Screening for mutants with alterations in fruit morphology generated by an activation tagging strategy resulted in the isolation of the ctf (constricted fruit) mutant. It is characterized by a) small and wrinkled fruits, with an enlarged replum, an amorphous structure of the septum and an irregular distribution of ovules and seeds; b) ectopic carpelloid structures in sepals bearing ovule-like structures and c) dwarf plants with curled rosette leaves. The overexpressed gene in ctf was AtMYB117, also named LOF1 (LATERAL ORGAN FUSION1). AtMYB117/LOF1 transcripts were localized in boundary regions of the vegetative shoot apical meristem and leaf primordia and in a group of cells in the adaxial base of petioles and bracts. Transcripts were also detected in the boundaries between each of the four floral whorls and during pistil development in the inner of the medial ridges, the placenta, the base of the ovule primordia, the epidermis of the developing septum and the outer cell layers of the ovule funiculi. Analysis of changes of expression of pistil-related genes in the ctf mutant showed an enhancement of SHATTERPROOF1 (SHP1) and SHP2 expression. All these results suggest that AtMYB117/LOF1 is recruited by a variety of developmental programs for the establishment of boundary regions, including the development of floral organs and the initiation of ovule outgrowth.
雌蕊和果实形态发生是一个复杂的基因网络的结果，目前还不完全清楚。需要寻找新的基因，以建立一个更全面的雌蕊和果实发育模型。通过激活标签策略筛选果实形态发生改变的突变体，导致了 ctf（收缩果实）突变体的分离。其特征为：a）果实小而皱，胎座增大，隔膜呈无定形结构，胚珠和种子分布不规则；b）萼片上带有胚珠样结构的副心皮结构；c）植株矮小，莲座叶卷曲。ctf 中过表达的基因是 AtMYB117，也称为 LOF1（LATERAL ORGAN FUSION1）。AtMYB117/LOF1 转录本定位于营养茎顶端分生组织和叶片原基的边界区域，以及叶柄和苞片近轴基部的一组细胞中。在四个花轮之间的边界以及内中脊、胎座、胚珠原基基部、发育中的隔膜表皮和胚珠珠柄外层细胞的内雌蕊发育过程中也检测到了转录本。ctf 突变体中与雌蕊相关基因表达变化的分析表明，SHATTERPROOF1（SHP1）和 SHP2 的表达增强。所有这些结果表明，AtMYB117/LOF1 被各种发育程序招募，用于建立边界区域，包括花器官的发育和胚珠生长的启动。
