RUI: Specification of Meristem Identity in Pea Inflorescences

被子植物花序模式的多样性可归因于一些基本计划的修改。其中一些修饰影响指定花序(I)和花(F)分生组织身份的基因。拟南芥（Arabidopsis）的LEAFY基因和牛头草（Antirrhinum）的FLORICAULA基因突变阻断或延迟了I向F的转化，使得末端（I-1）分生组织启动二级（I-2）分生组织，而不是花的分生组织。这些突变体与Pisum sativum花序的发育相似，其中I-1到I-2到F的转变反映了野生型表型。Pisum， Arabidopsis和Antirrhinum的分生组织同源基因功能的比较将解决进化修饰如何改变花序结构。这些实验的长期目标是建立调控Pisum花序发育的遗传等级。本研究主要关注三个分生组织识别基因：(1)DET (DETERMINATE)，被假设为I-1识别基因；(2) VEG (VEGETATIVE)，被认为指定I-2和/或F分生组织的同一性；(3) PIM（增殖花序分生组织），它似乎分配了F的同一性。利用这些基因的突变体，PI将探索分生组织身份基因之间的相互作用如何调节花序发育。与其他假定的分生组织特征基因的相互作用将被研究。突变分生组织的图像分析将用于确定分生组织特征基因的表达是否与分生组织的几何形状相关。最后，利用克隆的拟南芥和Antirrhinum分生组织识别基因对Pisum同源RFLP序列进行鉴定。这些RFLPs将被定位并检测与遗传鉴定的Pisum分生组织鉴定基因的联系。进一步的同源性将通过将Pisum分生组织同源突变体转化为Antirrhinum和Agrobacterium分生组织同源基因。这些拟议的遗传、形态学和分子实验将共同确定相似的基因是否（以及如何）产生I到F和I-1到I-2到F的花序模式。

Diverse angiosperm inflorescence patterns can be attributed to modifications of a few basic plans. Some of these modifications affect genes specifying inflorescence (I) and floral (F) meristem identity. Mutations of the LEAFY gene in Arabidopsis and the FLORICAULA gene in Antirrhinum block or delay the I to F transition so that the terminal (I-1) meristem initiates second order (I-2) meristems rather than floral meristems. These mutants have developmental parallels to Pisum sativum inflorescences where I-1 to I-2 to F transitions reflect the wild type phenotype. A comparison of meristem identity gene function in Pisum, Arabidopsis, and Antirrhinum will address how evolutionary modifications can alter inflorescence architecture. The long term goal of these experiments is to establish the genetic hierarchy regulating inflorescence development in Pisum. This proposal focuses on three meristem identity genes: (1) DET (DETERMINATE), which is hypothesized to be an I-1 identity gene; (2) VEG (VEGETATIVE), which is thought to specify I-2 and/or F meristem identity; and (3) PIM (PROLIFERATING INFLORESCENCE MERISTEM), which appears to assign F identity. Using mutants of these genes, the PI will explore how interactions between meristem identity genes regulate inflorescence deelopment. Interactions with other putative meristem identity genes will be investigated. Image analysis of mutant meristems will be used to ascertain if expression of meristem identity genes and meristem geometry correlate. Finally, cloned Arabidopsis and Antirrhinum meristem identity genes will be used to identify homologous RFLP (restriction fragment length polymorphisms) sequences in Pisum. These RFLPs will be mapped and tested for linkage with genetically identified Pisum meristem identity genes. Homology will be further tested by transformation of Pisum meristem identity mutants with Antirrhinum and Agrobacterium meristem identity genes. Together the proposed genetic, morphological, a nd molecular experiments will ascertain if (and how) similar genes can give rise to both I to F and I-1 to I-2 to F inflorescence patterns.