We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Enlarging Cells Initiating Apomixis in Hieracium praealtum Transition to an Embryo Sac Program prior to Entering Mitosis.
- Authors
Takashi Okada; Yingkao Hu; Tucker, Matthew R.; Taylor, Jennifer M.; Johnson, Susan D.; Spriggs, Andrew; Tsuchiya, Tohru; Oelkers, Karsten; Rodrigues, Julio C. M.; Koltunow, Anna M. G.
- Abstract
Hieracium praealtum forms seeds asexually by apomixis. During ovule development, sexual reproduction initiates with megaspore mother cell entry into meiosis and formation of a tetrad of haploid megaspores. The sexual pathway ceases when a diploid aposporous initial (AI) cell differentiates, enlarges, and undergoes mitosis, forming an aposporous embryo sac that displaces sexual structures. Embryo and endosperm development in aposporous embryo sacs is fertilization independent. Transcriptional data relating to apomixis initiation in Hieracium spp. ovules is scarce and the functional identity of the AI cell relative to other ovule cell types is unclear. Enlarging AI cells with undivided nuclei, early aposporous embryo sacs containing two to four nuclei, and random groups of sporophytic ovule cells not undergoing these events were collected by laser capture microdissection. Isolated amplified messenger RNA samples were sequenced using the 454 pyrosequencing platform and comparatively analyzed to establish indicative roles of the captured cell types. Transcriptome and protein motif analyses showed that approximately one-half of the assembled contigs identified homologous sequences in Arabidopsis (Arabidopsis thaliana), of which the vast majority were expressed during early Arabidopsis ovule development. The sporophytic ovule cells were enriched in signaling functions. Gene expression indicative of meiosis was notably absent in enlarging AI cells, consistent with subsequent aposporous embryo sac formation without meiosis. The AI cell transcriptome was most similar to the early aposporous embryo sac transcriptome when comparing known Functional annotations and both shared expressed genes involved in gametophyte development, suggesting that the enlarging AI cell is already transitioning to an embryo sac program prior to mitotic division.
- Subjects
HAWKWEEDS; MESSENGER RNA; PLANT embryology; OVULES; PLANT proteins; ARABIDOPSIS thaliana; GENE expression in plants; MEIOSIS; PLANTS
- Publication
Plant Physiology, 2013, Vol 163, Issue 1, p216
- ISSN
0032-0889
- Publication type
Article
- DOI
10.1104/pp.113.219485