Structure-function analysis of the interaction of secretory peptides with their target proteins
Plant Biochemistry and Biophysics
Final Report Abstract
The initial goal of the proposal – elucidating the molecular mechanism of maize CRP peptides with the potassium channel KZM1 by mutagenesis studies – was not successful. The quality of newly synthesized ZmES peptides as well as our own attempts to produce recombinant ZmES4 peptides did not fulfil the criteria to proceed with the planned mutagenesis studies. Our attempt to study the mechanism of the CRP peptide in planta – in in vitro grown maize pollen tubes – failed since for germination and subsequent electrophysiological analyses, maize pollen have to be harvested fresh (on a daily basis). Our greenhouse facilities however did not provide for producing flowering maize plants in sufficient quantity. Tobacco pollen tubes represent a versatile model system to study cell polarity by means of cell biology and electrophysiology. Based on a thorough transcriptomic approach we established now the molecular and genetic basis to study the fertilization process in general, and the role of ‘reproductive’ CRPs, in particular in this model system. Our data will be presented as a comprehensive database, publicly accessible to the scientific community. Together with recently published proteomic data our dataset represents a first starting point to study fertilization in solanaceous species. Most of our knowledge gained on plant sexual reproduction is currently obtained with Arabidopsis thaliana and has led – for example – to the identification of LURE-type CRPs as pollen tube attractants. Our studies have shown that also LTP-type CRPs play a prominent role in the fertilization process. Surprisingly and unexpectedly, these ‘reproductive’ LTPs impinge on pollen tube attraction and fertilization success via callose homeostasis in the female gametophyte. The underlying molecular mechanism is currently scant and needs to be addressed in future studies.
Publications
- (2021). Female gametophyte expressed Arabidopsis thaliana lipid transfer proteins AtLtpI.4 and AtLtpI.8 provide a link between callose homeostasis, pollen tube guidance, and fertilization success
Kumari, K., Zhao, M., Britz, S., Weiste, C., Dröge-Laser, W., Stigloher, C., Deeken, R., and Becker, D.
(See online at https://doi.org/10.1101/2021.01.13.426551)
