DeLong A, Calderon-Urrea A, Dellaporta S L
Department of Biology, Yale University, New Haven, Connecticut 06511.
Cell. 1993 Aug 27;74(4):757-68. doi: 10.1016/0092-8674(93)90522-r.
Maize produces separate unisexual flowers through programmed abortion of preformed organ primordia. In the male inflorescence (tassel), stamen primordia develop to sexual maturity, while gynoecia (pistil primordia) are aborted. In tasselseed2 (ts2) mutant plants, floral structures in the tassel adopt a female developmental program. Here we report the transposon tagging and cloning of the TS2 gene, which plays a late but pivotal role in determining the sexual fate of floral meristems. Shortly before abortion of the gynoecium, Ts2 mRNA is expressed subepidermally in that primordium. Phenotypic instability of the Activator (Ac)-induced allele ts2-m1 indicates that late restoration of TS2 action in somatic tissues, which is correlated with Ac excision, reactivates the male developmental program. The predicted amino acid sequence of the Ts2 protein shows significant similarity to short-chain alcohol dehydrogenases, particularly hydroxysteroid dehydrogenases.
玉米通过已形成的器官原基的程序性凋亡产生单独的单性花。在雄花序（雄穗）中，雄蕊原基发育至性成熟，而雌蕊（雌蕊原基）则凋亡。在玉米雌穗2（ts2）突变体植株中，雄穗中的花结构采用雌性发育程序。在此，我们报道了TS2基因的转座子标签法克隆，该基因在决定花分生组织的性命运中起后期但关键的作用。在雌蕊凋亡前不久，Ts2 mRNA在该原基的表皮下表达。激活子（Ac）诱导的等位基因ts2-m1的表型不稳定性表明，TS2在体细胞组织中的作用后期恢复，这与Ac切除相关，重新激活了雄性发育程序。Ts2蛋白的预测氨基酸序列与短链醇脱氢酶，特别是羟基类固醇脱氢酶有显著相似性。
