Abstract
The pollen tube is a fast tip-growing cell carrying the two sperm cells to the ovule allowing the double fertilization process and seed setting. To succeed in this process, the spatial and temporal controls of pollen tube growth within the female organ are critical. It requires a massive cell wall deposition to promote fast pollen tube elongation and a tight control of the cell wall remodeling to modify the mechanical properties. In addition, during its journey, the pollen tube interacts with the pistil, which plays key roles in pollen tube nutrition, guidance and in the rejection of the self-incompatible pollen. This review focuses on our current knowledge in the biochemistry and localization of the main cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species. Moreover, based on transcriptomic data and functional genomic studies, the possible enzymes involved in the cell wall remodeling during pollen tube growth and their impact on the cell wall mechanics are also described. Finally, mutant analyses have permitted to gain insight in the function of several genes involved in the pollen tube cell wall biosynthesis and their roles in pollen tube growth are further discussed.
Highlights
Fertilization of flowering plants requires the delivery of two sperm cells carried by the pollen tube, a fast tip-polarized growing cell, to the egg cell
We describe our current knowledge on the biosynthesis, distribution and biochemistry of cell wall polymers including pectin, hemicellulose, cellulose and callose from several pollen tube species
The presence of fucosylated and galactosylated XyG was assessed only recently in A. thaliana pollen tubes using CCRC-M1 [25,68] and LM15 [25]. Labeling with both monoclonal antibodies (mAbs) is detected in the entire pollen tube wall and at the electron microscopy level; it was shown that XyG is present in the outer and inner layers of the pollen tube cell wall [25] suggesting a possible interaction with cellulose microfibrils
Summary
Fertilization of flowering plants requires the delivery of two sperm cells carried by the pollen tube, a fast tip-polarized growing cell, to the egg cell. In plants such as Arabidopsis thaliana, this process begins with the adhesion of the pollen grains on the stigmatic papillae after the pollen coat has contacted the papillae (Figure 1a–d). During this invasive growth, pollen tubes are guided to the ovules via signals that need to pass through the cell wall to reach their membrane-associated or intracellular targets [4,5,6,7,8,9,10,11]. The enzymes from the male gametophyte and the female sporophytic counterpart possibly involved in the cell wall remodeling during pollen tube growth are further discussed in relation with the mechanical properties of the cell wall
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
