IPK Home

Functional Genomics of Developing Barley Seeds

Overview
700 EST Array
1,400 EST Array
12,000 EST Array
>>Affymetrix Array<<
Analysis Tools
Publications

Barley grain maturation and germination: Metabolic pathway and regulatory network commonalities and differences highlighted by new MapMan/PageMan profiling tools

Authors

Nese Sreenivasulu1+*, Björn Usadel2+, Andreas Winter1, Volodymyr Radchuk1, Uwe Scholz1, Nils Stein1, Winfriede Weschke1, Mark Strickert1, Timothy J Close3, Mark Stitt2, Andreas Graner1, Ulrich Wobus1,

1 Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstraße 3, D-06466 Gatersleben

2 Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam – Golm

3 Department of Botany and Plant Sciences, University of California, Riverside, California 92521

* Corresponding author

+ Authors contributed equally

Abstract

Plant seeds prepare for germination already during seed maturation. We performed a detailed transcriptome analysis of barley grain maturation, desiccation and germination in two tissue fractions (starchy endosperm/aleurone and embryo/scutellum) using the Affymetrix barley1 chip. To aid data evaluation, MapMan and PageMan tools, developed for Arabidopsis, were adapted to barley. The analysis allows a number of conclusions: (i) Cluster analysis revealed a smooth transition in transcription programs between late seed maturation and germination within embryo tissues, but not in the endosperm/aleurone. (ii) More than 12.000 transcripts are stored in the embryo of dry barley grains, of which many are presumably activated during germination. (iii) Transcriptional activation of storage reserve mobilization occurs at an early stage of germination, well before radicle protrusion. (iv) Key genes of GA biosynthesis are already active during grain maturation at a time when ABA peaks suggesting the formation of an endogenous store of GA in the aleurone, which acts later during germination in addition to newly synthesized GA. (v) Spatio-temporal expression data and cis-element searches in homologous rice promoters confirm an important gene-activating role of ABA during germination, in addition to the well known role of GA-response. The respective regulatory webs are linked to auxin and ethylene controlled networks. In summary, new bioinformatics PageMan and MapMan tools developed in barley has been successfully implicated to investigate the transcriptome relationships between seed maturation and germination in greater detail in an important crop plant.

Supplemental Matrial

Software