Huang Ming-Der, Wei Fu-Jin, Wu Cheng-Cheih, Hsing Yue-Ie Caroline, Huang Anthony H C
Institute of Plant and Microbial Biology, Academia Sinica, 11529 Taipei, Taiwan.
Plant Physiol. 2009 Feb;149(2):694-707. doi: 10.1104/pp.108.131128. Epub 2008 Dec 17.
The anthers in flowers perform important functions in sexual reproduction. Several recent studies used microarrays to study anther transcriptomes to explore genes controlling anther development. To analyze the secretion and other functions of the tapetum, we produced transcriptomes of anthers of rice (Oryza sativa subsp. japonica) at six progressive developmental stages and pollen with sequencing-by-synthesis technology. The transcriptomes included at least 18,000 unique transcripts, about 25% of which had antisense transcripts. In silico anther-minus-pollen subtraction produced transcripts largely unique to the tapetum; these transcripts include all the reported tapetum-specific transcripts of orthologs in other species. The differential developmental profiles of the transcripts and their antisense transcripts signify extensive regulation of gene expression in the anther, especially the tapetum, during development. The transcriptomes were used to dissect two major cell/biochemical functions of the tapetum. First, we categorized and charted the developmental profiles of all transcripts encoding secretory proteins present in the cellular exterior; these transcripts represent about 12% and 30% of the those transcripts having more than 100 and 1,000 transcripts per million, respectively. Second, we successfully selected from hundreds of transcripts several transcripts encoding potential proteins for lipid exine synthesis during early anther development. These proteins include cytochrome P450, acyltransferases, and lipid transfer proteins in our hypothesized mechanism of exine synthesis in and export from the tapetum. Putative functioning of these proteins in exine formation is consistent with proteins and metabolites detected in the anther locule fluid obtained by micropipetting.
花中的花药在有性生殖中发挥着重要作用。最近的几项研究使用微阵列来研究花药转录组，以探索控制花药发育的基因。为了分析绒毡层的分泌及其他功能，我们利用合成测序技术，对水稻（粳稻亚种）花药在六个连续发育阶段以及花粉的转录组进行了研究。这些转录组包含至少18,000个独特转录本，其中约25%有反义转录本。通过计算机模拟进行花药减去花粉的消减分析，产生了主要为绒毡层特有的转录本；这些转录本包括其他物种中所有已报道的直系同源绒毡层特异性转录本。转录本及其反义转录本的差异发育图谱表明，在花药发育过程中，尤其是绒毡层中，基因表达受到广泛调控。这些转录组被用于剖析绒毡层的两个主要细胞/生化功能。首先，我们对所有编码存在于细胞外的分泌蛋白的转录本的发育图谱进行了分类和绘制；这些转录本分别占每百万转录本超过100和1000的转录本的约12%和30%。其次，我们成功地从数百个转录本中筛选出了几个在花药早期发育过程中编码潜在脂质外壁合成蛋白的转录本。在我们假设的绒毡层中外壁合成及输出机制中，这些蛋白包括细胞色素P450、酰基转移酶和脂质转运蛋白。这些蛋白在花粉外壁形成中的假定功能与通过微量移液器获得的花药腔液中检测到的蛋白质和代谢物一致。
