PM H+-ATPase is a potential target of hormone signaling during pollen tube growth in petunia

  • L. V. Kovaleva
  • A. S. Voronkov
  • E. V. Zakharova
  • G. V. Timofeeva

Abstract

Aim. Pollen tube growth is the best known example of highly polarized plant cell expansion. This process is known to require intensive exocytosis at the tip which is supported by dynamic cytoskeleton, vesicle trafficking, and functioning of ion transporters in pollen tube plasma membrane (PM). We have attempted to test the possibility of plant hormones functioning as signal molecules in progamic phase of fertilization. Methods. The effects of exogenous plant hormones, indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin A3 (GA3), and cytokinin (kinetin) on the growth, PM polarization of in vitro germinating petunia (Petunia hybrida L.) pollen tubes were investigated. Results. Growth-stimulated effects of IAA, ABA and GA3 were accompanied by orthovanadate-sensitive hyperpolarization of PM suggesting possible involvement of PM H+-ATPase activation in this process. Fluorescent labeling the enzyme with H+-ATPase antibodies exhibited IAA- and ABA-induced lateral membrane redistribution of it into the subapical zone of pollen tube PM. Conclusions. All these results, taken together, indicate the potential target of hormone signaling in pollen tubes, PM H+-ATPase, related to the hormone-induced modulation of the above mentioned characteristics of this proton pump.
Keywords: Petunia hybrida, Pollen tube, PM H+-ATPase, phytohormones.

References

Feijo J.A., Malho R., Obermeyer G. Ion dynamics and its possible role during in vitro pollen germination and tube growth. Protoplasma. 1995. V. 187. P. 155-167. doi: 10.1007/BF01280244

Holdaway-Clarke T.L., Hepler P.K. Control of pollen tube growth: role of ion gradients and fluxe. New Phytol. 2003. V. 159. P. 539-563. doi: 10.1046/j.1469-8137.2003.00847.x

Hepler P.K. The cytoskeleton and its regulation by calcium and protons. Plant Physiol. 2016. V. 170. P. 3-22. doi: 10.1104/pp.15.01506

Kovaleva L., Zakharova E. Hormonal status of the pollen-pistil system at the progamic phase of fertilization after compatible and incompatible pollination in Petunia hybrida L.. Sex Plant Reprod. 2003. V. 16. P. 191-196. doi: 10.1007/s00497-003-0189-1

Kovaleva L.V., Zakharova E.V., Minkina Y.V., Voronkov A.S. Effects of flavonols and phytohormones on germination and growth of petunia male gametophyte. Allelopathy J. 2009. V. 23. P. 51-62.

Kovaleva L.V., Voronkov A.S., Zakharova E.V. Role of auxin and cytokinin in the regulation of the actin cytoskeleton in the vitro germinating male gametophyte of petunia. Russ J. Plant Physiol. 2015. V. 62. P. 179-186. doi: 10.1134/S1021443715020107

Lang V., Pertl-Obermeyer H., Safiarian M.J., Obermeyer G. Pump up the volume - a central role for the plasma membrane H (+) pump in pollen germination and tube growth. Protoplasma. 2014. V. 251. P. 477-488. doi: 10.1007/s00709-013-0555-2

Certal A.C., Almeida R.B., Carvalho L.M., Wong E., Moreno N., Michard E., Carmeiro J., Rodriguezleon J., Wu H.M., Cheung A.Y., Feijo J.A. Exclusion of a proton ATPase from the apical membrane is associated with cell polarity and tip growth in Nicotiana tabacum pollen tubes. Plant Cell. 2008. V. 20. P. 614-634. doi: 10.1105/tpc.106.047423

Grabski S., Schindler M. Auxins and cytokinins as antipodal modulators of elasticity within the actin network of plant cells. Plant Physiol. 1996. V. 110. P. 965-970. doi: 10.1104/pp.110.3.965