Targeted gene disruption of glycerol-3-phosphate dehydrogenase in Colletotrichum gloeosporioides reveals evidence that glycerol is a significant transferred nutrient from host plant to fungal pathogen.
Unidirectional transfer of nutrients from plant host to pathogen represents a most revealing aspect of the parasitic lifestyle of plant pathogens. Whereas much effort has been focused on sugars and amino acids, the identification of other significant metabolites is equally important for comprehensive characterization of metabolic interactions between plants and biotrophic fungal pathogens. Employing a strategy of targeted gene disruption, we generated a mutant strain (gpdhDelta) defective in glycerol-3-phosphate dehydrogenase in a hemibiotrophic plant pathogen, Colletotrichum gloeosporioides f.sp. malvae. The gpdhDelta strain had severe defects in carbon utilization as it could use neither glucose nor amino acids for sustained growth. Although the mutant mycelia were able to grow on potato dextrose agar medium, they displayed arrhythmicity in growth and failure to conidiate. The metabolic defect of gpdhDelta could be entirely ameliorated by glycerol in chemically defined minimal medium. Furthermore, glycerol was the one and only metabolite that could restore rhythmic growth and conidiation of gpdhDelta. Despite the profound defects in carbon source utilization, in planta the gpdhDelta strain exhibited normal pathogenicity, proceeded normally in its life cycle, and produced abundant conidia. Analysis of plant tissues at the peripheral zone of fungal infection sites revealed a time-dependent reduction in glycerol content. This study provides strong evidence for a role of glycerol as a significant transferred metabolite from plant to fungal pathogen.
Wei
Yangdou
Y
Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada. yangdou.wei@usask.ca
Shen
Wenyun
W
Dauk
Melanie
M
Wang
Feng
F
Selvaraj
Gopalan
G
Zou
Jitao
J
D031583:Althaea / Q000382:microbiology; D020231:Colletotrichum / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D017353:Gene Deletion; D005816:Genetic Complementation Test; D005990:Glycerol / Q000378:metabolism*; D005993:Glycerolphosphate Dehydrogenase / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010935:Plant Diseases / Q000382:microbiology; D021381:Protein Transport; D015183:Restriction Mapping
D005993:Glycerolphosphate Dehydrogenase; D005990:Glycerol