Calderon-Urrea A, Dellaporta S L
Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA.
Development. 1999 Feb;126(3):435-41. doi: 10.1242/dev.126.3.435.
The formation of unisexual flowers in maize requires the selective elimination and sexual maturation of floral organs in an initially bisexual floral meristem. Elimination of pistil primordia occurs in the primary and secondary florets of the tassel spikelets, and in the secondary florets of ear spikelets. Ill-fated pistil cells undergo a cell death process associated with nuclear degeneration in a specific spatial-temporal pattern that begins in the subepidermis, eventually aborting the entire organ. The sex determination genes tasselseed1 and tasselseed2 are required for death of pistil cells. tasselseed1 is required for the accumulation of TASSELSEED2 mRNA in pistil cells. All pistil primordia express TASSELSEED2 RNA but functional pistils found in ear spikelets are protected from cell death by the action of the silkless1 gene. silkless1 blocks tasselseed-induced cell death in the pistil primordia of primary ear florets. A model is proposed for the control of pistil fate by the action of the ts1-ts2-sk1 pathway.
玉米中两性花向单性花的转变需要在最初两性的花分生组织中对花器官进行选择性消除和性成熟。雌蕊原基的消除发生在雄穗小穗的初级和次级小花以及雌穗小穗的次级小花中。命运多舛的雌蕊细胞会经历一个与核退化相关的细胞死亡过程，该过程以特定的时空模式开始于表皮下，最终导致整个器官败育。性别决定基因tasselseed1和tasselseed2是雌蕊细胞死亡所必需的。tasselseed1是雌蕊细胞中TASSELSEED2 mRNA积累所必需的。所有雌蕊原基都表达TASSELSEED2 RNA，但在雌穗小穗中发现的功能性雌蕊通过silkless1基因的作用免受细胞死亡的影响。silkless1可阻止tasselseed诱导的初级雌穗小花雌蕊原基中的细胞死亡。本文提出了一个由ts1-ts2-sk1途径的作用控制雌蕊命运的模型。
