454 transcriptome sequencing suggests a role for two-component signalling in cellularization and differentiation of barley endosperm transfer cells454转录组测序表明双组分信号的作用在cellularization和大麦胚乳传递细胞的分化.pdf

454 Transcriptome Sequencing Suggests a Role for Two- Component Signalling in Cellularization and Differentiation of Barley Endosperm Transfer Cells 1 2 1 1 1 1 Johannes Thiel *, Julien Hollmann , Twan Rutten , Hans Weber , Uwe Scholz , Winfriede Weschke ¨ ¨ 1 Leibniz-Institut fur Pflanzengenetik und Kulturpflanzenforschung (IPK), Gatersleben, Germany, 2 Botanisches Institut, Christian-Albrechts-Universitat, Kiel, Germany Abstract Background: Cell specification and differentiation in the endosperm of cereals starts at the maternal-filial boundary and generates the endosperm transfer cells (ETCs). Besides the importance in assimilate transfer, ETCs are proposed to play an essential role in the regulation of endosperm differentiation by affecting development of proximate endosperm tissues. We attempted to identify signalling elements involved in early endosperm differentiation by using a combination of laser- assisted microdissection and 454 transcriptome sequencing. Principal Findings: 454 sequencing of the differentiating ETC region from the syncytial state until functionality in transfer processes captured a high proportion of novel transcripts which are not available in existing barley EST databases. Intriguingly, the ETC-transcriptome showed a high abundance of elements of the two-component signalling (TCS) system suggesting an outstanding role in ETC differentiation. All components and subfamilies of the TCS, including distinct kinds of membrane-bound receptors, have been identified to be expressed in ETCs. The TCS system represents an ancient