Functional Characterization of fst1 in Fusarium verticillioides During Colonization of Maize Kernels

Abstract

The putative hexose transporter gene fst1 in Fusarium verticillioides was identified previously by microarray analysis as a gene that was more highly expressed during colonization of autoclaved maize endosperm than germ. In contrast to a previous study, in which disruption of fst1 did not affect growth of the pathogen on autoclaved maize kernels, in the current study, we demonstrated that disruption of fst1 delayed growth and symptom development on wounded maize ears. Characterization of the fst1 promoter revealed that regulation of fst1 expression was similar to that of fumonisin biosynthetic (fum) genes; expression was highest during growth on endosperm tissue and repressed by elevated concentrations of ammonium in the growth medium. With a fluorescent tag attached to FST1, the protein localized transiently to the periphery of the cells near the plasma membrane and in vacuole-like structures, suggesting that membrane-localized FST1 was internalized and degraded in vacuoles. Expression of fst1 in a yeast strain lacking hexose transporter genes did not complement the yeast mutation, suggesting that FST1 does not transport glucose, fructose, or mannose. The results indicate a functional role for FST1 in pathogenesis during the colonization of living kernels.

Metabolome and Transcriptome of the Interaction between Ustilago maydis and Fusarium verticillioides In Vitro

“…Among these are Fst1, Fst2, Fst3, and Fst6 (FVEG_08441, FVEG_13078, FVEG_05690, and FVEG_10089, respectively). Fst1 is a putative sugar transporter, involved in the production of fumonisin B 1 , and is important to the colonization of maize (14).…”

Extensive Intra-Kingdom Horizontal Gene Transfer Converging on a Fungal Fructose Transporter Gene

“…The Botryotinia fuckeliana Fsy1 homologue was shown to mediate fructose uptake in a manner that was not inhibited by glucose, although no kinetic parameters for initial uptake rates are available. On the other hand, expression of the Fsy1 homologue from Fusarium verticillioides in S. cerevisiae failed to restore fructose transport in a strain devoid of hexose transporters but it is presently unclear whether this could be due to incorrect subcellular localization of the heterologous protein [68]. Finally, it should be noted that all Fsy1 proteins tested so far are also capable of transporting sorbose, albeit to various extents.…”

An antibody that confers plant disease resistance targets a membrane‐bound glyoxal oxidase in Fusarium

“…Thirty spikes were inoculated for each strain and the number of spikelets with FHB symptoms was counted 21 d post inoculation (dpi). Virulence assays of the Fv strains were carried out via pin-bar wounding of maize kernels with a maize hybrid (S167 9 Z85) as previously described (Kim & Woloshuk, 2011). Ten ears (10 kernels per ear) were inoculated for each strain and the lesion sizes of the inoculated kernels were measured 14 dpi.…”