Magnaporthe grisea is a fungal pathogen that infects rice leaves and causes rice blast, a devastating crop disease. W. grisea produces active elicitors of the hypersensitive response in rice that were previously identified as ceramide monohexosides (CMHs). Using several chromatographic approaches, mass spectrometry, and nuclear magnetic resonance, we identified ceramide mono- and dihexosides (CDH) in purified lipid extracts from M. grisea cells. As described by other authors, CMH consists of a ceramide moiety containing 9-methyl-4,8-sphingadienine in amidic linkage to 2-hydroxyoctadecenoic or 2-hydroxyhexadecenoic acids and a carbohydrate segment consisting of one residue of glucose. CDHs, however, contain β-galactose (1→4)-linked to β-glucose as sugar units and phytosphingosine as the long-chain base, bound to a C24 alpha-hydroxylated fatty acid. To our knowledge, this is the first report on the occurrence of CDH in a fungal species and illustrates the existence of an alternative path of ceramide glycosylation in fungal cells

Magnaporthe grisea, glucosylceramide, phytosphingosine, ceramide dihexoside

There are 4 chemically distinct structures. Please, select:
bDGalp(1-4)bDGlcp(1-?)CER bDGalp(1-4)bLGlcp(1-?)CER bLGalp(1-4)bDGlcp(1-?)CER bLGalp(1-4)bLGlcp(1-?)CER

SVGMWSMILES3D molIonize

 

R1 = CER
[1*]O[C@@H]1O[C@H](CO)[C@@H](O[C@@H]2O[C@H](CO)[C@H](O)[C@H](O)[C@H]2O)[C@H](O)[C@H]1O

341.289 g/mol (C₁₂H₂₁RO₁₁, R = residue superclass(es), not counted in mol weight)

The structure of cotylenin A, a potent plant-growth stimulant with the most complex molecule in cotylenins from Cladosporium fungus sp. 501-7W, was analyzed again by HMBC experiments and X-ray crystallography of its diacetyl-dihydroderivative, The previously proposed stereostructure of cotylenin A was thus completely confirmed.

X-ray crystallography, cotylenin A, stereostructure, NMR assignment

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11
6,6	Me	59.271
6	aDSugp	101.39	72.82	81.33	106.05	66.31	70.04	103.97	85.24	52.72	44.15	18.45
	Subst


1H NMR data:
Linkage	Residue	H1	H2	H3	H4	H5	H6	H7	H8	H9	H10	H11
6,6	Me	3.409
6	aDSugp	5.089	3.622	4.064	-	4.364	3.67-3.72	5.565	-	3.145	2.79-2.83	1.056
	Subst


1H/13C HSQC data:
Linkage	Residue	C1/H1	C2/H2	C3/H3	C4/H4	C5/H5	C6/H6	C7/H7	C8/H8	C9/H9	C10/H10	C11/H11
6,6	Me	59.271/3.409
6	aDSugp	101.39/5.089	72.82/3.622	81.33/4.064		66.31/4.364	70.04/3.67-3.72	103.97/5.565		52.72/3.145	44.15/2.79-2.83	18.45/1.056
	Subst

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

COC[C@H]1O[C@H](O[C@@H]2C3=C(C(C)C)CC[C@]3(C)/C=C3\[C@H](CC[C@]3(O)COC)[C@@H](C)[C@H]2O)[C@H](O)[C@H]2OC3O[C@@]12O[C@@]3(C)[C@H]1CO1

622.752 g/mol (C₃₃H₅₀O₁₁)