Plant Defensins NaD1 and NaD2 Induce Different Stress Response Pathways in Fungi.
Nicotiana alata defensins 1 and 2 (NaD1 and NaD2) are plant defensins from the ornamental tobacco that have antifungal activity against a variety of fungal pathogens. Some plant defensins interact with fungal cell wall O-glycosylated proteins. Therefore, we investigated if this was the case for NaD1 and NaD2, by assessing the sensitivity of the three Aspergillus nidulans (An) O-mannosyltransferase (pmt) knockout (KO) mutants (An∆pmtA, An∆pmtB, and An∆pmtC). An∆pmtA was resistant to both defensins, while An∆pmtC was resistant to NaD2 only, suggesting NaD1 and NaD2 are unlikely to have a general interaction with O-linked side chains. Further evidence of this difference in the antifungal mechanism was provided by the dissimilarity of the NaD1 and NaD2 sensitivities of the Fusarium oxysporum f. sp. lycopersici (Fol) signalling knockout mutants from the cell wall integrity (CWI) and high osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathways. HOG pathway mutants were sensitive to both NaD1 and NaD2, while CWI pathway mutants only displayed sensitivity to NaD2.
Plant Breeding Institute Cobbitty, The University of Sydney, Private Bag 4011, Narellan, NSW 2567, Australia. peter.dracatos@sydney.edu.au.
Peter M
PM
Dracatos
La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia. ja2payne@gmail.com.
Jennifer
J
Payne
Departamento de Genética, Campus de Excelencia Internacional Agroalimentario ceiA3, Universidad de Córdoba, Córdoba 14071, Spain. ge2dipia@uco.es.
Antonio
A
Di Pietro
La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia. m.anderson@latrobe.edu.au.
Marilyn A
MA
Anderson
Department of Animal, Plant and Soil Sciences, AgriBio, La Trobe University, Bundoora, VIC 3083, Australia. k.plummer@latrobe.edu.au.
Kim M
KM
Plummer
D001233:Aspergillus nidulans / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D002473:Cell Wall / Q000187:drug effects / Q000378:metabolism; D023082:Defensins / Q000494:pharmacology*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005670:Fusarium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008364:Mannosyltransferases / Q000235:genetics / Q000378:metabolism; D009997:Osmotic Pressure; D014026:Nicotiana / Q000737:chemistry*
D023082:Defensins; D005656:Fungal Proteins; D008364:Mannosyltransferases
CWI signalling pathway; HOG signalling pathway; NaD1 and NaD2; antifungal defensins