Suspensor Length Determines Developmental Progression of the Embryo in Arabidopsis

• Published in: Plant physiology (Bethesda) 2013-07, Vol.162 (3), p.1448-1458
• Main Authors: Babu, Yashodar, Musielak, Thomas, Henschen, Agnes, Bayer, Martin
• Format: Article
• Language: English
• Subjects: Arabidopsis - growth & development; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell growth; Cell Wall - metabolism; Cell walls; Developmental delay; Developmental stages; Embryogenesis; Embryos; Endosperm; Gene Expression Regulation, Plant; GENES, DEVELOPMENT, AND EVOLUTION; Genetic Complementation Test; Glycoside Hydrolases - genetics; Interleukin-1 Receptor-Associated Kinases - genetics; Mutation; Phenotypes; Plants; Plants, Genetically Modified; Pollen; Polygalacturonase - genetics; Polygalacturonase - metabolism; Seedlings - genetics; Seeds - anatomy & histology; Seeds - cytology; Seeds - growth & development; Seeds - ultrastructure
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.113.217166

The first structure that differentiates during plant embryogenesis is the extra-embryonic suspensor that positions the embryo in the lumen of the seed. A central role in nutrient transport has been ascribed to the suspensor in species with prominent suspensor structures. Little is known, however, about what impact the size of the rather simple Arabidopsis (Arabidopsis thaliana) suspensor has on embryogenesis. Here, we describe mutations in the predicted exo-polygalacturonase gene NIMNA (NMA) that lead to cell elongation defects in the early embryo and markedly reduced suspensor length. Mutant nma embryos develop slower than wild-type embryos, and we could observe a similar developmental delay in another mutant with shorter suspensors. Interestingly, for both genes, the paternal allele has a stronger influence on the embryonic phenotype. We conclude that the length of the suspensor is crucial for fast developmental progression of the embryo in Arabidopsis.