Abstract:
Malonyl-CoA-ACP transacetylase
（
FabD） catalyzes the conversion of malonyl-CoA to malonyl-ACP， the second step in the fatty acid synthesis pathway， playing a crucial role in the growth of
Fusarium graminearum. To reveal the biological function of
FgFabD， the wild type strain of
Fusarium graminearum PH-1 was used.
FgFabD deletion mutants （Δ
FgFabD） and complementary strains （Δ
FgFabD-C） were constructed by Split-Marker gene knockout technology. PH-1， Δ
FgFabD and Δ
FgFabD-C were individually inoculated in different cultural conditions to analyze the growth characters， and to reveal the effect of
FgFabD on the growth， development， pathogenesis and mycotoxin productions. The results demonstrated that the growth rate and colony phenotype of Δ
FgFabD showed no significant difference to wild strain PH-1 in regular medium. In the stress selection medium containing 0.7 mol/L NaCl， 0.03% H
2O
2， 0.01% SDS and 300 μg/mL Congo-Red， the growth of Δ
FgFabD mutant was significantly lower than wild-type strain PH-1. The evidence demonstrated that
FgFabD gene played important roles in the formation of cell membrane and cell wall. The conidia production of
fusarium graminearum was significantly reduced compared to wild strain PH-1. Inoculation experiments showed that the pathogenicity of the mutant on wheat coleoptiles and wheat heads was significantly lower than that of the wild-type strain. Rice medium inoculation tests further demonstrated that the DON produced by Δ
FgFabD was significantly lower than that produced by wild strain. These results demonstrated that
FgFabD played key roles in the asexual reproduction， pathogenicity and DON biosynthesis of
F. graminearum.
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