Development of maternal seed tissue in barley is mediated by regulated cell expansion and cell disintegration and coordinated with endosperm growth
Open Access
- 8 November 2010
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 62 (3), 1217-1227
- https://doi.org/10.1093/jxb/erq348
Abstract
After fertilization, filial grain organs are surrounded by the maternal nucellus embedded within the integuments and pericarp. Rapid early endosperm growth must be coordinated with maternal tissue development. Parameters of maternal tissue growth and development were analysed during early endosperm formation. In the pericarp, cell proliferation is accomplished around the time of fertilization, followed by cell elongation predominantly in longitudinal directions. The rapid cell expansion coincides with endosperm cellularization. Distribution of TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling)-positive nuclei reveals distinct patterns starting in the nucellus at anthesis and followed later by the inner cell rows of the pericarp, then spreading to the whole pericarp. The pattern suggests timely and spatially regulated programmed cell death (PCD) processes in maternal seed tissues. When the endosperm is coenocytic, PCD events are only observed within the nucellus. Thereby, remobilization of nucellar storage compounds by PCD could nourish the early developing endosperm when functional interconnections are absent between maternal and filial seed organs. Specific proteases promote PCD events. Characterization of the barley vacuolar processing enzyme (VPE) gene family identified seven gene members specifically expressed in the developing grain. HvVPE2a (known as nucellain) together with closely similar HvVPE2b and HvVPE2d might be involved in nucellar PCD. HvVPE4 is strongly cell specific for pericarp parenchyma. Correlative evidence suggests that HvVPE4 plays a role in PCD events in the pericarp. Possible functions of PCD in the maternal tissues imply a potential nutritive role or the relief of a physical restraint for endosperm growth. PCD could also activate post-phloem transport functions.Keywords
This publication has 38 references indexed in Scilit:
- Phytaspase, a relocalisable cell death promoting plant protease with caspase specificityThe EMBO Journal, 2010
- Spatiotemporal Profiling of Starch Biosynthesis and Degradation in the Developing Barley GrainPlant Physiology, 2009
- Different Hormonal Regulation of Cellular Differentiation and Function in Nucellar Projection and Endosperm Transfer Cells: A Microdissection-Based Transcriptome Study of Young Barley GrainsPlant Physiology, 2008
- The origin and evolution of plant cystatins and their target cysteine proteinases indicate a complex functional relationshipBMC Evolutionary Biology, 2008
- Are metacaspases caspases?The Journal of cell biology, 2007
- Genome-wide identification and expression analysis of rice cell cycle genesPlant Molecular Biology, 2007
- JekyllEncodes a Novel Protein Involved in the Sexual Reproduction of BarleyTHE PLANT CELL ONLINE, 2006
- A cellular suicide strategy of plants: vacuole-mediated cell deathApoptosis, 2006
- A Vacuolar Processing Enzyme, δVPE, Is Involved in Seed Coat Formation at the Early Stage of Seed DevelopmentTHE PLANT CELL ONLINE, 2005
- Vacuolar Processing Enzymes Are Essential for Proper Processing of Seed Storage Proteins in Arabidopsis thalianaOnline Journal of Public Health Informatics, 2003