Sexual Plant Reproduction

, Volume 15, Issue 2, pp 65–74

Serine esterases are required for pollen tube penetration of the stigma in Brassica

  • Simon J. Hiscock
  • Dominic Bown
  • Sarah J. Gurr
  • Hugh G. Dickinson
Original Article

DOI: 10.1007/s00497-002-0143-7

Cite this article as:
Hiscock, S.J., Bown, D., Gurr, S.J. et al. Sex Plant Reprod (2002) 15: 65. doi:10.1007/s00497-002-0143-7

Abstract.

We have investigated the diversity of serine esterases in pollen and stigma tissues of Brassica napus and the role of these enzymes in pollen germination and pollen tube penetration of the stigma. The serine esterase-specific inhibitor diisopropyl fluorophosphate was used as a probe in a tritiated form, [3H]-DIPF, to determine the number and diversity of serine esterases in crude protein extracts from pollen and stigma. Seven serine esterases were identified in pollen and at least seven serine esterases were identified in stigma. The most abundant enzymes had molecular weights of 30–50 kDa. In the pollen extract a serine esterase was detected with the same molecular weight, 22 kDa, as an esterase previously shown to be a cutinase. Only one serine esterase (40 kDa) appeared to be shared between pollen and stigma extracts. Butyrate esterase activity in pollen and stigma extracts was assayed using p-nitrophenyl butyrate (PNB), an ester substrate frequently used in 'cutinase' assays. Total PNBase activity in pollen and stigma extracts was shown to be significantly reduced by the serine esterase inhibitors DIPF and ebelactone B. When DIPF and ebelactone B were applied to stigmas prior to pollination, pollen germination was not significantly affected but, at the highest inhibitor concentrations, up to 70% of germinating pollen tubes failed to penetrate the stigma surface. These data demonstrate that serine esterases, most probably cutinase(s), are required for pollen tube penetration of the dry cuticularised Brassica stigma.

Serine esterase Cutinase Pollen Pollen tube penetration Brassica

Copyright information

© Springer-Verlag 2002

Authors and Affiliations

  • Simon J. Hiscock
    • 1
  • Dominic Bown
    • 1
  • Sarah J. Gurr
    • 1
  • Hugh G. Dickinson
    • 1
  1. 1.Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
  2. 2.Present address: School of Biological Sciences, University of Bristol, Woodland Road, Bristol, BS8 1UG, UK, e-mail: simon.hiscock@bristol.ac.uk, Tel.: +44-117-9546835, Fax: +44-117-9257374