Cardenas, Luis , Santana, O , Nava, Noreide , Quinto, Carmen .
Spatio-temporal analysis of actin polymerization sites in living root hair cells responding to specific Nod factors.
Legumes can obtain nitrogen through a symbiotic interaction with rhizobial bacteria. This process involves a molecular dialogue among the two partners in which legume roots exude flavonoids that induce the expression of bacterial nodulation genes. These encode proteins involved in the synthesis and secretion of specific lipochitooligosaccharides, the so-called Nod factors (NFs). These molecules trigger changes in root hair morphology, plant gene expression, cortical cell dedifferentiation and mitosis, depolarization of root hair cell membrane potential, and actin cytoskeleton rearrangements. Herein, we show that sublethal concentrations of fluorescently labeled cytochalasin (Fl-Cyt) which binds to plus ends of microfilaments can image those sites, where actin polimerization occurs. Utilizing this approach we addressed the role of actin polymerization in Phaseolus vulgaris living root hair cells, during normal apical growth and under NFs treatment. Using these conditions the distribution of the actin polymerization sites was observed at the tip of growing root hair cells. P. vulgaris root hair cells loaded with Fl-Cyt and then challenged with specific NFs, showed an immediate and augmented fluorescent signal. This suggests that newly formed plus ends are generated in the presence of NFs, which may result from severed microfilaments creating the conditions for the swelling response and root hair growth reinitiation in response to NFs. Partially supported by grants from DGAPA/UNAM, IN228903 (LC), IN204907(CQ) and CONACyT 42560-Q (CQ).
Log in to add this item to your schedule
1 - Universidad Nacional Autonoma de Mexico, Biologia Molecular de Plantas
2 - Universidad Nacional Autonoma de Mexico, Biologia Molecular de Plantas, Av Universidad 2001, Chamilpa, Cuernavaca, Morelos, 62210, Mexico
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM