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Received Aug 3, 2017; Revised Nov 26, 2017; Accepted Dec 3, 2017
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1. Introduction
Inflorescences are the reproductive architectures of plants, composed of stems, stalks, bracts, and flowers. Poaceae (also called Gramineae) is one of the largest families in the monocotyledonous flowering plants, including the major cereal crops, such as maize (Zea mays L.), rice (Oryza sativa L.), and wheat (Triticum aestivum L.). Inflorescences of this family are characterized by their panicle or spike shapes [1], complex branches, and unique spikelets, as well as inconspicuous and anemophilous flowers without obvious petals and sepals [2, 3]. Species in the genus Triticum takes the shape of the spike with the spikelets, each containing one or more florets, attached to rachis nodes. The wheat floret consists of a carpel with its ovary, style, and stigma, with three anthers attached to the base through slender filaments, which are enclosed by bract-like organs called lemma and palea.
Inflorescence development and regulation have attracted great attention from plant biologists and crop breeders since they are crucial for reproduction of flowering plants and for production of food grains in cereal crops. Although the key genes regulating the flower initiation and development are conserved in higher plants [4, 5], the diversity of reproductive structure and behaviors is still not well explained. Transcriptomes reflect the complete set of RNA transcripts expressed by the genome under developmentally or physiologically distinct states; therefore, its comparison allows identification of genes under common regulation. High-throughput methods, such as serial analysis of gene expression (SAGE) [6], microarray technology [7], and next-generation sequencing [8] have enabled transcriptome studies in an unprecedented scale in many plant species, especially in those with full genome sequence information available. This has led to the discovery of a number of genes involved in flower development. These genes display tempo-spatial expression patterns not only in transcriptome level [9–12] but also at the proteome level, such as those in pollen development of tomatoes [13], indicating their strictly regulated functions. Anther tissues were used in most of these studies because they are easy to...