CONICET | Buscador de Institutos y Recursos Humanos

Polarized growth involves the expansion of the cell tip, stimulating cell elongation in only one direction. In plants, growing pollen tubes, root hairs and cotton fibers are examples of polarized growth. Pollen tube growth is a highly-coordinated process, where processes such as actin cytoskeletal arrangement, vesicle mobility, regulation of cell wall integrity and reactive oxygen species (ROS) and calcium (Ca2+) dynamics are involved. Adequate signaling from the external cell wall to the pollen tube cytoplasm is necessary to sustain a proper growth. We have reported that two pollen peptides, RALF4 and RALF19, from the RAPID ALKALINIZATION FACTORs (RALFs) family, act redundantly to regulate the pathway that controls growth and integrity of the pollen tubes (1). Furthermore, we have demonstrated that proteins of the LEUCINE-RICH EXTENSIN (LRX) family, that directly interact with the RALFs, regulate changes in cell wall integrity of pollen tubes (2).Comprehension of how these RALFs and LRXs control pollen tube growth will bring us closer to fully understand the mechanisms that govern plant reproduction. The pollen tube is a highly suitable and affordable model to understand how autocrine and paracrine signals participate in different stages during pollination and how pollen tubes transduce that information to adapt their growth.(1) RALF4/19 peptides interact with LRX proteins to control pollen tube growth in Arabidopsis. Mecchia, Santos-Fernandez, Duss, Somoza, Boisson-Dernier, Gagliardini, Martínez-Bernardini, Ndinyanka-Fabrice, Ringli, Muschietti* and Grossniklaus*. Science. 22 Dec 2017: Vol. 358, Issue 6370, pp. 1600-1603. (2) Arabidopsis pollen extensins LRX are required for cell wall integrity during pollen tube growth. Sede, Borassi, Wengier, Mecchia, Estevez* and Muschietti*. FEBS Letter. 2018 Jan 592(2):233-243.