The C-terminal propeptide of a plant defensin confers cytoprotective and subcellular targeting functions

Lay, Fung T., Poon, Simon, McKenna, James A., Connelly, Angela A., Barbeta, Barbara L., McGinness, Bruce S., Fox, Jennifer L., Daly, Norelle L., Craik, David J., Heath, Robyn L. and Anderson, Marilyn A. (2014) The C-terminal propeptide of a plant defensin confers cytoprotective and subcellular targeting functions. BMC Plant Biology, 14 1: 41.1-41.13. doi:10.1186/1471-2229-14-41

Author Lay, Fung T.
Poon, Simon
McKenna, James A.
Connelly, Angela A.
Barbeta, Barbara L.
McGinness, Bruce S.
Fox, Jennifer L.
Daly, Norelle L.
Craik, David J.
Heath, Robyn L.
Anderson, Marilyn A.
Title The C-terminal propeptide of a plant defensin confers cytoprotective and subcellular targeting functions
Journal name BMC Plant Biology   Check publisher's open access policy
ISSN 1471-2229
Publication date 2014-02-05
Year available 2014
Sub-type Article (original research)
DOI 10.1186/1471-2229-14-41
Open Access Status DOI
Volume 14
Issue 1
Start page 41.1
End page 41.13
Total pages 13
Place of publication London, United Kingdom
Publisher BioMed Central Ltd
Language eng
Abstract Background: Plant defensins are small (45-54 amino acids), basic, cysteine-rich proteins that have a major role in innate immunity in plants. Many defensins are potent antifungal molecules and are being evaluated for their potential to create crop plants with sustainable disease resistance. Defensins are produced as precursor molecules which are directed into the secretory pathway and are divided into two classes based on the absence (class I) or presence (class II) of an acidic C-terminal propeptide (CTPP) of about 33 amino acids. The function of this CTPP had not been defined.Results: By transgenically expressing the class II plant defensin NaD1 with and without its cognate CTPP we have demonstrated that NaD1 is phytotoxic to cotton plants when expressed without its CTPP. Transgenic cotton plants expressing constructs encoding the NaD1 precursor with the CTPP had the same morphology as non-transgenic plants but expression of NaD1 without the CTPP led to plants that were stunted, had crinkled leaves and were less viable. Immunofluorescence microscopy and transient expression of a green fluorescent protein (GFP)-CTPP chimera were used to confirm that the CTPP is sufficient for vacuolar targeting. Finally circular dichroism and NMR spectroscopy were used to show that the CTPP adopts a helical confirmation.Conclusions: In this report we have described the role of the CTPP on NaD1, a class II defensin from Nicotiana alata flowers. The CTPP of NaD1 is sufficient for vacuolar targeting and plays an important role in detoxification of the defensin as it moves through the plant secretory pathway. This work may have important implications for the use of defensins for disease protection in transgenic crops.
Keyword Phytotoxicity
Plant defensin
Transgenic cotton
Vacuolar targeting
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID DP0453107
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
Institute for Molecular Bioscience - Publications
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