Cell–cell communication and signalling pathways within the ovule: from its inception to fertilization

Abstract

SummaryCell-cell communication pervades every aspect of the life of a plant. It is particularly crucial for the development of the gametes and their subtle interaction leading to double fertilization. The ovule is composed of a funiculus, one or two integuments, and a gametophyte surrounded by nucellus tissue. Proper ovule and embryo sac development are critical to reproductive success. To allow fertilization, the correct relative positioning and differentiation of the embryo sac cells are essential. Integument development is also intimately linked with the normal development of the female gametophyte; the sporophyte and gametophyte are not fully independent tissues. Inside the gametophyte, numerous signs of cell-cell communication take place throughout development, including cell fate patterning, fertilization and the early stages of embryogenesis. This review highlights the current evidence of cell-cell communication and signalling elements based on structural and physiological observations as well as the description and characterization of mutants in structurally specific genes. By combining data from different species, models of cell-cell interactions have been built, particularly for the establishment of the germline, for the progression through megagametogenesis and for double fertilization.

Cross-Talk Between Sporophyte and Gametophyte Generations Is Promoted by CHD3 Chromatin Remodelers inArabidopsis thaliana

“…The haploid male and female gametophyte generation is contained within the diploid sporophyte, and development of these genetically distinct tissues is highly interdependent (Ma and Sundaresan 2010;Niklas and Kutschera 2010). The female gametophyte develops within the sporophytic ovary, where it forms into an embryo sac as it is surrounded by the diploid sporophytic integuments of the ovule (Bencivenga et al 2011;Chevalier et al 2011). Characterization of ovule-defective mutants in Arabidopsis thaliana has revealed that female gametophyte development is dependent on the sporophyte, particularly integument development, and has also identified a variety of factors that contribute to this relationship including transcription factors, kinases, and components of plant hormone signal transduction pathways (Bencivenga et al 2011;Shi and Yang 2011;Vielle-Calzada et al 2012).…”

Protein Interaction Network of Arabidopsis thaliana Female Gametophyte Development Identifies Novel Proteins and Relations

“…Additionally, downregulated AHP2 (one of the six Arabidopsis thaliana histidine phosphotransfer proteins) involved in phosphorelay signaling system was predicted in the network. It appears that AHP2 plays a central role in signaling pathway during FG development [55]. The current network also shows interaction for DD39 with pollen development and ECA3.…”

“…MYB98 plays specific roles in synergids and pollen tube guidance during FG development [1]. Although little is known about cell-cell communication, recently Chevalier et al (2011) [55] pointed evidences for existence of cell-cell communication and signaling pathways during FG development. Interestingly, in the present network, signaling pathways and signal transduction were predicted as overrepresented GO terms (Table S6).…”

Arabidopsis PRC1 core component AtRING1 regulates stem cell-determining carpel development mainly through repression of class I KNOX genes

“…Thus, AtRING1a/b coordinate ovule development in both sporophytic and gametophytic phases. Many gametophytic ovule mutants have normal sporophytic tissue structures, but sporophytic ovule mutants usually have abnormal gametophyte development, suggesting that integument and ES development are interdependent processes and that accurate architecture of sporophytic tissue is necessary for successful development of a fully functional gametophyte [52]. For example, bell1 ( bel1 ) ovules develop a single integument-like structure (ILS) taking the place of the two integuments, and fail to produce a normal ES [36, 53, 54].…”