Inactivation of the catalytic subunit of cAMP-dependent protein kinase A causes delayed appressorium formation and reduced pathogenicity of Colletotrichum gloeosporioides.
The cyclic AMP- (cAMP-) dependent protein kinase A signaling pathway is one of the major signaling pathways responsible for regulation of the morphogenesis and pathogenesis of several pathogenic fungi. To evaluate the role of this pathway in the plant pathogenic fungus, Colletotrichum gloeosporioides, the gene encoding the catalytic subunit of cAMP-dependent protein kinase A, CgPKAC, was cloned, inactivated, and the mutant was analyzed. Analysis of the Cgpkac mutant generated via gene replacement showed that the mutants were able to form appressoria; however, their formation was delayed compared to the wild type. In addition, the mutant conidia underwent bipolar germination after appressoria formation, but no appressoria were generated from the second germ tube. The mutants also showed reduced ability to adhere to a hydrophobic surface and to degrade lipids localized in the appressoria. Based on the number of lesions produced during a pathogenicity test, the mutant's ability to cause disease in healthy mango fruits was reduced, which may be due to failure to penetrate into the fruit. These findings indicate that cAMP-dependent protein kinase A has an important role in regulating morphogenesis and is required for pathogenicity of C. gloeosporioides.
School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Selangor, 43600 Bangi, Malaysia.
Tri Puji
TP
Priyatno
Farah Diba
FD
Abu Bakar
Nurhaida
N
Kamaruddin
Nor Muhammad
NM
Mahadi
Abdul Munir
AM
Abdul Murad
D001483:Base Sequence; D020134:Catalytic Domain; D020231:Colletotrichum / Q000201:enzymology / Q000472:pathogenicity*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D017931:DNA Primers
D017931:DNA Primers; D017868:Cyclic AMP-Dependent Protein Kinases