In Fusarium verticillioides, a ubiquitous pathogen of maize, virulence and mycotoxigenesis are regulated in response to the types and amounts of carbohydrates present in maize kernels. In this study, we investigated the role of a putative hexokinase-encoding gene (HXK1) in growth, development and pathogenesis. A deletion mutant (Δhxk1) of HXK1 was not able to grow when supplied with fructose as the sole carbon source, and growth was impaired when glucose, sucrose or maltotriose was provided. Additionally, the Δhxk1 mutant produced unusual swollen hyphae when provided with fructose, but not glucose, as the sole carbon source. Moreover, the Δhxk1 mutant was impaired in fructose uptake, although glucose uptake was unaffected. On maize kernels, the Δhxk1 mutant was substantially less virulent than the wild-type, but virulence on maize stalks was not impaired, possibly indicating a metabolic response to tissue-specific differences in plant carbohydrate content. Finally, disruption of HXK1 had a pronounced effect on fungal metabolites produced during colonization of maize kernels; the Δhxk1 mutant produced approximately 50 % less trehalose and 80 % less fumonisin B1 (FB1) than the wild-type. The reduction in trehalose biosynthesis likely explains observations of increased sensitivity to osmotic stress in the Δhxk1 mutant. In summary, this study links early events in carbohydrate sensing and glycolysis to virulence and secondary metabolism in F. verticillioides, and thus provides a new foothold from which the genetic regulatory networks that underlie pathogenesis and mycotoxigenesis can be unravelled and defined.
BluhmB. H.,
KimH.,
ButchkoR. A. E.,
WoloshukC. P.(2008). Involvement of ZFR1 of Fusarium verticillioides in kernel colonization and the regulation of FST1, a putative sugar transporter gene required for fumonisin biosynthesis on maize kernels. Mol Plant Pathol 9:203–211 [View Article][PubMed]
BrownD. W.,
ButchkoR. A.,
BusmanM.,
ProctorR. H.(2007). The Fusarium verticillioides FUM gene cluster encodes a Zn(II)2Cys6 protein that affects FUM gene expression and fumonisin production. Eukaryot Cell 6:1210–1218 [View Article][PubMed]
DoehlemannG.,
BerndtP.,
HahnM.(2006). Trehalose metabolism is important for heat stress tolerance and spore germination of Botrytis cinerea
. Microbiology 152:2625–2634 [View Article][PubMed]
FillingerS.,
ChaverocheM. K.,
van DijckP.,
de VriesR.,
RuijterG.,
TheveleinJ.,
d’EnfertC.(2001). Trehalose is required for the acquisition of tolerance to a variety of stresses in the filamentous fungus Aspergillus nidulans
. Microbiology 147:1851–1862[PubMed]
FlahertyJ. E.,
WoloshukC. P.(2004). Regulation of fumonisin biosynthesis in Fusarium verticillioides by a zinc binuclear cluster-type gene, ZFR1
. Appl Environ Microbiol 70:2653–2659 [View Article][PubMed]
FlahertyJ. E.,
PirttiläA. M.,
BluhmB. H.,
WoloshukC. P.(2003).PAC1, a pH-regulatory gene from Fusarium verticillioides
. Appl Environ Microbiol 69:5222–5227 [View Article][PubMed]
FlipphiM.,
van de VondervoortP. J.,
RuijterG. J.,
VisserJ.,
ArstH. N.Jr,
FelenbokB.(2003). Onset of carbon catabolite repression in Aspergillus nidulans. Parallel involvement of hexokinase and glucokinase in sugar signaling. J Biol Chem 278:11849–11857 [View Article][PubMed]
FosterA. J.,
JenkinsonJ. M.,
TalbotN. J.(2003). Trehalose synthesis and metabolism are required at different stages of plant infection by Magnaporthe grisea
. EMBO J 22:225–235 [View Article][PubMed]
GaddG. M.,
ChalmersK.,
ReedR. H.(1987). The role of trehalose in dehydration resistance of Saccharomyces cerevisiae
. FEMS Microbiol Lett 48:249–254 [View Article]
GerberR.,
LouL.,
HuffmanJ.,
ZhuX.,
LinT.,
LiL. Q.,
ArreguinI.,
ButchkoR. A. E.,
ProctorR. H.,
DuL.(2009). Advances in understanding the biosynthesis of fumonisins. Mycotoxin Prevention and Control in Agriculture167–182AppellM.,
KendraD. F.,
TrucksesM. W.
Washington, DC: American Chemical Society;
HarringtonG. N.,
BushD. R.(2003). The bifunctional role of hexokinase in metabolism and glucose signaling. Plant Cell 15:2493–2496 [View Article][PubMed]
HendricksK. A.,
SimpsonJ. S.,
LarsenR. D.(1999). Neural tube defects along the Texas-Mexico border, 1993–1995. Am J Epidemiol 149:1119–1127[PubMed][CrossRef]
HohmannS.,
WinderickxJ.,
de WindeJ. H.,
ValckxD.,
CobbaertP.,
LuytenK.,
de MeirsmanC.,
RamosJ.,
TheveleinJ. M.(1999). Novel alleles of yeast hexokinase PII with distinct effects on catalytic activity and catabolite repression of SUC2
. Microbiology 145:703–714 [View Article][PubMed]
HounsaC. G.,
BrandtE. V.,
TheveleinJ.,
HohmannS.,
PriorB. A.(1998). Role of trehalose in survival of Saccharomyces cerevisiae under osmotic stress. Microbiology 144:671–680 [View Article][PubMed]
KimH.,
WoloshukC. P.(2008). Role of AREA, a regulator of nitrogen metabolism, during colonization of maize kernels and fumonisin biosynthesis in Fusarium verticillioides
. Fungal Genet Biol 45:947–953 [View Article][PubMed]
KuettnerE. B.,
KettnerK.,
KeimA.,
SvergunD. I.,
VolkeD.,
SingerD.,
HoffmannR.,
MüllerE. C.,
OttoA. et al.(2010). Crystal structure of hexokinase KlHxk1 of Kluyveromyces lactis: a molecular basis for understanding the control of yeast hexokinase functions via covalent modification and oligomerization. J Biol Chem 285:41019–41033 [View Article][PubMed]
LafonA.,
SeoJ. A.,
HanK. H.,
YuJ. H.,
d’EnfertC.(2005). The heterotrimeric G-protein GanB(α)-SfaD(β)-GpgA(γ) is a carbon source sensor involved in early cAMP-dependent germination in Aspergillus nidulans
. Genetics 171:71–80 [View Article][PubMed]
LarkinM. A.,
BlackshieldsG.,
BrownN. P.,
ChennaR.,
McGettiganP. A.,
McWilliamH.,
ValentinF.,
WallaceI. M.,
WilmA. et al.(2007).clustalw and clustalx version 2.0. Bioinformatics 23:2947–2948 [View Article][PubMed]
LaurentinA.,
EdwardsC. A.(2003). A microtiter modification of the anthrone-sulfuric acid colorimetric assay for glucose-based carbohydrates. Anal Biochem 315:143–145 [View Article][PubMed]
LewisJ. G.,
LearmonthR. P.,
WatsonK.(1995). Induction of heat, freezing and salt tolerance by heat and salt shock in Saccharomyces cerevisiae
. Microbiology 141:687–694 [View Article][PubMed]
NelsonP. E.,
DesjardinsA. E.,
PlattnerR. D.(1993). Fumonisins, mycotoxins produced by Fusarium species: biology, chemistry, and significance. Annu Rev Phytopathol 31:233–252 [View Article][PubMed]
NgamskulrungrojP.,
HimmelreichU.,
BregerJ. A.,
WilsonC.,
ChayakulkeereeM.,
KrockenbergerM. B.,
MalikR.,
DanielH. M.,
ToffalettiD. et al.(2009). The trehalose synthesis pathway is an integral part of the virulence composite for Cryptococcus gattii
. Infect Immun 77:4584–4596 [View Article][PubMed]
OzcanS.,
DoverJ.,
JohnstonM.(1998). Glucose sensing and signaling by two glucose receptors in the yeast Saccharomyces cerevisiae
. EMBO J 17:2566–2573 [View Article][PubMed]
RheederJ. P.,
MarasasW. F.,
VismerH. F.(2002). Production of fumonisin analogs by Fusarium species. Appl Environ Microbiol 68:2101–2105 [View Article][PubMed]
RomanoA. H.(1982). Facilitated diffusion of 6-deoxy-d-glucose in bakers’ yeast: evidence against phosphorylation-associated transport of glucose. J Bacteriol 152:1295–1297[PubMed]
RuiO.,
HahnM.(2007). The Botrytis cinerea hexokinase, Hxk1, but not the glucokinase, Glk1, is required for normal growth and sugar metabolism, and for pathogenicity on fruits. Microbiology 153:2791–2802 [View Article][PubMed]
ShimW. B.,
WoloshukC. P.(2001). Regulation of fumonisin B1 biosynthesis and conidiation in Fusarium verticillioides by a cyclin-like (C-type) gene, FCC1
. Appl Environ Microbiol 67:1607–1612 [View Article][PubMed]
ShimW. B.,
FlahertyJ. E.,
WoloshukC. P.(2003). Comparison of fumonisin B1 biosynthesis in maize germ and degermed kernels by Fusarium verticillioides
. J Food Prot 66:2116–2122[PubMed]
SmithJ. E.,
BluhmB. H.(2011). Metabolic fingerprinting in Fusarium verticillioides to determine gene function. Fungal Genomics: Methods in Molecular Biology237–247XuJ. R.,
BluhmB. H.
Totowa, NJ: Humana Press; [View Article]
SmithJ. E.,
LayJ. O.,
BluhmB. H.(2011). Metabolic fingerprinting reveals a new genetic linkage between ambient pH and metabolites associated with desiccation tolerance in Fusarium verticillioides
. Metabolomics [View Article]
WarfieldC. Y.,
GilchristD. G.(1999). Influence of kernel age on fumonisin B1 production in maize by Fusarium moniliforme
. Appl Environ Microbiol 65:2853–2856[PubMed]
XiaoW.,
SheenJ.,
JangJ. C.(2000). The role of hexokinase in plant sugar signal transduction and growth and development. Plant Mol Biol 44:451–461 [View Article][PubMed]