Establishment and Maintenance of the Barley Inflorescence Meristem

点击翻译按钮获取中文摘要

Plant stem cells represent undifferentiated meristematic tissue destined to divide and to provide growth postembryonically. During growth and development specified cell lineages further differentiate, ultimately forming organs and the entire plant. The embryo-derived root apical meristem (RAM) and the shoot apical meristem (SAM) are the first plant meristems formed. Depending on environmental and positional cues, cells from the SAM adopt strategies to specify so called secondary meristems, thereby shaping overall above-ground plant architecture. The first reproductive meristem, i.e. inflorescence meristem (IM), provides the foundation for all floral variation. Intriguingly, in all of these early developmental events of patterning and morphogenesis, hormonal regulation in concerted action together with transcriptional regulators drive development; in fact, one of such important regulators belongs to the family of homeodomain (HD) containing WOX (WUSCHEL-related homeobox) proteins that define various roles during stem cell niche patterning, cell division and organ formation.In cereal crops IM establishment, maintenance and signaling are not at all well understood, as compared to Arabidopsis. Fundamental knowledge in terms of cellular positioning of the SAM / IM stem cell niche, organizing cells or peripheral zone is completely missing in many important cereal crops including barley (Hordeum vulgare L.). If we want to better understand how a barley inflorescence, called spike, is formed, a more fundamental insight into the cellular patterning of the shoot apex is clearly essential.The major working hypothesis of this research project is that barley WOX (HvWOX) genes play an important role during the establishment and maintenance of the barley IM, and that newly evolved and diverged HvWOX gene regulation has occurred in barley (and possibly Triticeae). This project therefore seeks (i) deeper insights into the Triticeae/grass WOX protein phylogeny, (ii) to obtain a refined and cell-resolved transcript analyses of relevant HvWOX and potential stem cell marker genes, (iii) to use HvWOX transgenic reporter lines to check cellular localization as well as cell-to-cell movement, and finally (iv) to characterize mutated HvWOX genes phenotypically.