Genetics/Genomics

Abstract

CS-22-5 - Tetraspanin-binding partners act as negative regulators of sperm cell adhesion impairing double fertilization in Arabidopsis thaliana

Tuesday, July 17
9:53 AM - 10:13 AM

In flowering plants, two separate gametic fusions mark the fertilization process as one of the most impressive examples of heterotypic cell-cell recognition in plant development. Several core factors were identified to regulate male-female gamete adhesion, activation and fusion, but how homotypic cellular interactions between plant gametes of the same sex contribute to the success of double fertilization is still poorly understood.
Within the mature pollen grain, stable adhesion contacts physically couple the membranes of both twin sperm cells (SCs) and one of the SCs to the vegetative nucleus (VN) forming a structural assembly, named the male germ unit (MGU). Upon pollen tube burst within the female gametophyte, these adhesion contacts should disassemble to facilitate a one-to-one male-female gamete interaction.
Scaffolding proteins are known to regulate the stability of adhesion complexes through physical interactions with core components or by mobilizing additional regulatory proteins to the adhesion contact. Tetraspanins (TETs) are scaffold proteins present in all multicellular organisms that play important roles in cell adhesion, fusion, motility, and cell-cell signaling, but their functions in plants is poorly understood. In an earlier report, we provided the first evidences that AtTET11/AtTET12, accumulate in a remarkably stable membrane microdomain in the adhesion contact of both sperm cells (SCs)[1]. We identified a functional link for two plant-specific TET-binding partners (TBP) in sperm cells. The tbp8/9 double mutant presents an enhanced SC-SC adhesion and severe fertility defects caused by unbalanced fertilization events. These results sustain the proposed functional concept of a “TET web” in which TETs can function as membrane scaffold proteins, clustering signaling complexes at the cell surface of plant gametes that regulate cell-cell interactions, such as gamete adhesion and fusion.

[1] Boavida, L. C., Qin, P., Broz, M., Becker, J. D., and McCormick, S. (2013). Plant Physiol, 163: 696-712.


 

Co-Authors

Chandra Misra – Instituto Gulbenkian de Ciência; Nikita Bhatnagar – Purdue University, Department of Botany and Plant Pathology, Center for Plant Biology; Jörg Becker – Instituto Gulbenkian de Ciência

Leonor C. Boavida, PhD

Assistant Professor
Purdue University - Department of Botany and Plant Pathology, Purdue Center of Plant Biology

Presentation(s):

Send Email for Leonor C. Boavida


Assets

CS-22-5 - Tetraspanin-binding partners act as negative regulators of sperm cell adhesion impairing double fertilization in Arabidopsis thaliana



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Tetraspanin-binding partners act as negative regulators of sperm cell adhesion impairing double fertilization in Arabidopsis thaliana