Zea mays Transcriptome or Gene expression. Zea mays

Transcriptomes from multiple pre-meiotic stages of wild type, mac1, and msca1 maize anthers were characterized by microarray hybridization. The goal was to characterize the developmental progression as the anther specifies five cell types and grows rapidly precedeing meiotic entry. The stages characterized were immature anther primordia (0.15 mm long in maize) containing just stem cells, through somatic and germinal cell fate specification (0.20 and 0.25 mm), mitotic proliferation (0.4 mm), and finally the birth of the middle layer and tapetum (0.7 mm). To obtain cell-type specific markers, at 0.7 mm we also compared whole anthers to collections of laser-microdissected anther cell types including the archesporial cells (pre-meiotic germinal cells), nutritive layers (middle layer and tapetum) and structural layers (endothecium and epidemis) of the anther lobe. keyword: anther development, maize, male-sterile Overall design: Three loop designs covered the early stages (up to 0.7 mm) with two replicates for each comparison. The first loop had 0.2 mm long anthers and compared wild type versus mac1 mutant versus msca1 mutant in a three vertex loop design. The second loop had four vertices and compared 0.15 mm WT anther primordia, 0.25 mm WT anthers, 0.4 mm WT anthers and finally 0.4 mm mac1 mutant anthers. The third had 0.7 mm anthers in a three vertex loop with the nutritive layers (middle layer and tapetum) at one vertex, the germinal pre-meiotic cells at another vertex, and whole anthers at a third vertex. The whole anther samples were also, separately and outside of the loop, compared in four replicates to the structural layers (endothecium and epidermis).

本研究通过微阵列杂交（microarray hybridization）技术，对野生型、mac1突变体及msca1突变体玉米花药的多个减数分裂前时期转录组进行了表征分析。本研究的目标是解析花药特化5种细胞类型并在减数分裂起始前快速生长过程中的发育进程。本次分析涵盖的发育时期包括：仅含干细胞的未成熟花药原基（玉米中长度为0.15 mm），体细胞与生殖细胞命运特化时期（长度0.20 mm与0.25 mm），有丝分裂增殖时期（0.4 mm），最终到中层与绒毡层（tapetum）形成时期（0.7 mm）。为获取细胞类型特异性标记基因，我们在0.7 mm时期对完整花药与激光显微切割（laser-microdissected）得到的花药细胞类型进行了比对，所涉及的细胞类型包括花药瓣的造孢细胞（archesporial cells，减数分裂前生殖细胞）、营养层（中层与绒毡层）以及结构层（药室内壁（endothecium）与表皮（epidermis））。
关键词：花药发育、玉米、雄性不育
实验设计概述：共采用3套循环设计覆盖早期发育阶段（直至0.7 mm），每组比较均设置2次生物学重复。第一套循环设计针对0.2 mm长度的花药，采用三顶点循环设计比对野生型（Wild Type, WT）、mac1突变体与msca1突变体的转录组差异。第二套循环设计包含四个顶点，比对的样本包括0.15 mm野生型（WT）花药原基、0.25 mm野生型花药、0.4 mm野生型花药以及0.4 mm mac1突变体花药。第三套循环设计针对0.7 mm花药，采用三顶点循环设计，三个顶点分别为营养层（中层与绒毡层）、减数分裂前生殖细胞以及完整花药。此外，我们还脱离循环设计单独设置了4次重复，将完整花药样本与结构层（药室内壁与表皮）样本进行比对。