Magnaporthe grisea cutinase2 mediates appressorium differentiation and host penetration and is required for full virulence.
The rice blast fungus Magnaporthe grisea infects its host by forming a specialized infection structure, the appressorium, on the plant leaf. The enormous turgor pressure generated within the appressorium drives the emerging penetration peg forcefully through the plant cuticle. Hitherto, the involvement of cutinase(s) in this process has remained unproven. We identified a specific M. grisea cutinase, CUT2, whose expression is dramatically upregulated during appressorium maturation and penetration. The cut2 mutant has reduced extracellular cutin-degrading and Ser esterase activity, when grown on cutin as the sole carbon source, compared with the wild-type strain. The cut2 mutant strain is severely less pathogenic than the wild type or complemented cut2/CUT2 strain on rice (Oryza sativa) and barley (Hordeum vulgare). It displays reduced conidiation and anomalous germling morphology, forming multiple elongated germ tubes and aberrant appressoria on inductive surfaces. We show that Cut2 mediates the formation of the penetration peg but does not play a role in spore or appressorium adhesion, or in appressorial turgor generation. Morphological and pathogenicity defects in the cut2 mutant are fully restored with exogenous application of synthetic cutin monomers, cAMP, 3-isobutyl-1-methylxanthine, and diacylglycerol (DAG). We propose that Cut2 is an upstream activator of cAMP/protein kinase A and DAG/protein kinase C signaling pathways that direct appressorium formation and infectious growth in M. grisea. Cut2 is therefore required for surface sensing leading to correct germling differentiation, penetration, and full virulence in this model fungus.
Skamnioti
Pari
P
Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom.
Gurr
Sarah J
SJ
D000268:Adhesiveness / Q000187:drug effects; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D056229:Fungal Structures / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D015966:Gene Expression Regulation, Fungal / Q000187:drug effects; D005800:Genes, Fungal; D006790:Host-Parasite Interactions / Q000187:drug effects; D057927:Hydrophobic and Hydrophilic Interactions; D020082:Magnaporthe / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity* / Q000648:ultrastructure; D008563:Membrane Lipids / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000382:microbiology*; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology; D011433:Propranolol / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014774:Virulence / Q000187:drug effects; D014970:Xanthines / Q000494:pharmacology
D004075:Diglycerides; D008563:Membrane Lipids; D012333:RNA, Messenger; D014970:Xanthines; C000521:cutin; D011433:Propranolol; D000242:Cyclic AMP; D002265:Carboxylic Ester Hydrolases; C019952:cutinase
Br J Pharmacol. 2006 Jan;147 Suppl 1:S27-37
16402114
Mol Gen Genet. 1992 Mar;232(2):183-90
1557024
Plant Cell. 2000 May;12(5):721-38
10810146
Mol Plant Microbe Interact. 2002 Mar;15(3):183-92
11952120
Appl Environ Microbiol. 1996 Feb;62(2):456-60
8593048
Science. 1999 Sep 17;285(5435):1896-9
10489364
Plant Cell. 1995 Nov;7(11):1869-78
8535140
Nature. 2005 Apr 21;434(7036):980-6
15846337
J Biol Chem. 2002 Mar 8;277(10):7905-12
11756444
Mol Plant Microbe Interact. 2002 May;15(5):437-44
12036274
Proc Natl Acad Sci U S A. 1998 Oct 13;95(21):12713-8
9770551
Plant Cell. 1994 Jul;6(7):935-45
8069105
Biochem Soc Trans. 2005 Apr;33(Pt 2):384-8
15787612
EMBO J. 2007 Apr 18;26(8):2158-68
17396154
Plant Cell. 1996 Jun;8(6):985-999
12239409
J Comput Biol. 2007 Jan-Feb;14(1):68-83
17381347
Methods Enzymol. 1999;310:91-109
10547784
Mol Plant Pathol. 2005 Sep 1;6(5):561-75
20565680
Science. 1988 Jan 15;239(4837):288-90
17769992
Plant Cell. 1999 Oct;11(10):2013-30
10521529
Nature. 1992 Apr 16;356(6370):615-8
1560844
Science. 1979 Aug 3;205(4405):507-8
17758793
EMBO J. 2007 Feb 7;26(3):690-700
17255942
Plant Cell. 1992 Sep;4(9):1101-1111
12297669
Mol Plant Microbe Interact. 1997 Apr;10(3):355-68
9100380
Genetics. 1991 Jan;127(1):87-101
2016048
Proc Natl Acad Sci U S A. 1995 May 9;92(10):4080-7
7753774
Mol Plant Microbe Interact. 2003 Jun;16(6):545-52
12795380
Mol Microbiol. 2004 Sep;53(6):1695-707
15341648
Plant Cell. 1992 Jun;4(6):621-9
1392588
Mol Microbiol. 2003 Oct;50(1):231-43
14507377
Mol Gen Genet. 1992 Mar;232(2):174-82
1557023
Genome Biol. 2005;6(3):R24
15774025
Proc Natl Acad Sci U S A. 1986 Mar;83(6):1704-8
16593666
Annu Rev Phytopathol. 2001;39:385-417
11701871
Curr Opin Plant Biol. 2006 Jun;9(3):281-7
16580871
Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):11281-4
1837147
Trends Biochem Sci. 2003 Mar;28(3):118-21
12633989
Plant Cell. 1993 Jun;5(6):693-700
12271080
Nucleic Acids Res. 2001 May 1;29(9):e45
11328886
Plant J. 2003 Oct;36(2):155-64
14535881
Annu Rev Phytopathol. 1997;35:211-34
15012522
Mol Plant Pathol. 2005 May 1;6(3):257-67
20565655
Plant Cell. 1998 Aug;10(8):1361-74
9707535
Mol Microbiol. 2005 Sep;57(5):1224-37
16101997
Mol Plant Pathol. 2001 Nov 1;2(6):327-37
20573022
Nature. 2006 Mar 23;440(7083):535-9
16554820
Annu Rev Phytopathol. 2003;41:399-427
12651963
Plant Cell. 2005 Apr;17(4):1317-29
15749760
Genes Dev. 1996 Nov 1;10(21):2696-706
8946911
Annu Rev Microbiol. 1996;50:491-512
8905089
Mol Plant Microbe Interact. 1997 Jan;10(1):30-8
9002270
Biochemistry. 1975 Jul;14(13):2824-31
1156575
Mol Plant Microbe Interact. 2007 May;20(5):568-80
17506334
Plant Cell. 1999 Oct;11(10):2045-58
10521531
Annu Rev Microbiol. 2003;57:177-202
14527276
Plant Cell. 1993 Nov;5(11):1575-90
8312740
Plant Cell. 1997 Nov;9(11):1973-83
9401122
Plant J. 2007 Mar;49(6):972-80
17257167
Mol Plant Microbe Interact. 1997 Dec;10(9):1075-86
9390422
Proc Natl Acad Sci U S A. 2001 Jun 5;98(12):6963-8
11391010
Plant Cell. 2006 Feb;18(2):321-39
16415209
PLoS Med. 2006 Dec;3(12):e528
17194200
Anal Chem. 2004 Aug 1;76(15):4452-8
15283587