Cell wall dynamics and gene expression on soybean embryonic axes during germination

• Published in: Planta 2019-10, Vol.250 (4), p.1325-1337
• Main Authors: Sangi, Sara, Santos, Maria L. C., Alexandrino, Camilla R., Da Cunha, Maura, Coelho, Fernanda S., Ribeiro, Gabrielly P., Lenz, Dominik, Ballesteros, Helkin, Hemerly, Adriana S., Venâncio, Thiago M., Oliveira, Antônia E. A., Grativol, Clícia
• Format: Article
• Language: English
• Subjects: Agriculture; Axes (reference lines); Biomedical and Life Sciences; Biosynthesis; Cell growth; Cell Wall - metabolism; Cell walls; Cellulose; Ecology; Embryos; Forestry; Gene expression; Gene Expression Regulation, Plant; Gene regulation; Genes; Genome, Plant - genetics; Genomes; Germination; Glycine max - genetics; Glycine max - growth & development; Life Sciences; ORIGINAL ARTICLE; Plant Sciences; Seed germination; Seedlings; Seedlings - genetics; Seedlings - growth & development; Seeds; Seeds - genetics; Seeds - growth & development; Soybeans; Structural analysis; Transcription; Water balance
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-019-03231-1

Cell wall is a highly organized and dynamic structure that provides mechanical support for the cell. During seed germination, the cell wall is critical for cell growth and seedling establishment. Although seed germination has been widely studied in several species, key aspects regarding the regulation of cell wall dynamics in germinating embryonic axes remain obscure. Here, we characterize the gene expression patterns of cell wall pathways and investigate their impact on the cell wall dynamics of embryonic axes of germinating soybean seeds. We found 2143 genes involved in cell wall biosynthesis and assembly in the soybean genome. Key cell wall genes were highly expressed at specific germination stages, such as expansins, UDP-Glc epimerases, GT family, cellulose synthases, peroxidases, arabinogalactans, and xyloglucans-related genes. Further, we found that embryonic axes grow through modulation of these specific cell wall genes with no increment in biomass. Cell wall structural analysis revealed a defined pattern of cell expansion and an increase in cellulose content during germination. In addition, we found a clear correlation between these structural changes and expression patterns of cell wall genes during germination. Taken together, our results provide a better understanding of the complex transcriptional regulation of cell wall genes that drive embryonic axes growth and expansion during soybean germination.