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Fusarium graminearum is one of the causal agents of Fusarium head blight and produces the trichothecene mycotoxin, deoxynivalenol (DON). Thioredoxin reductases (TRRs) play critical roles in the recycling of oxidized thioredoxin. However, their functions are not well known in plant pathogenic fungi. In this study, we characterized a TRR orthologue FgTRR in F. graminearum. The FgTRR-GFP fusion protein localized to the cytoplasm. FgTRR gene deletion demonstrated that FgTRR is involved in hyphal growth, conidiation, sexual reproduction, DON production, and virulence. The ΔTRR mutants also exhibited a defect in pigmentation, the expression level of aurofusarin biosynthesis-related genes was significantly decreased in the FgTRR mutant. Furthermore, the ΔTRR mutants were more sensitive to oxidative stress and aggravated apoptosis-like cell death compared with the wild type strain. Taken together, these results indicate that FgTRR is important in development and pathogenicity in F. graminearum.

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The Ascomycete fungus Fusarium graminearum, the causal agent of Fusarium head blight of wheat and barley, has become a predominant model organism for the study of fungal phytopathogens. Aquaporins (AQPs) have been implicated in the transport of water, glycerol, and a variety of other small molecules in yeast, plants and animals. However, the role of these proteins in phytopathogenic fungi is not well understood. Here, we identified and attempted to elucidate the function of the five aquaporin genes in F. graminearum. The phylogenetic analysis revealed that FgAQPs are divided into two clades, with FgAQP1 in the first clade. The ∆AQP1 mutant formed whitish colonies with longer aerial hyphae and reduced conidiation and perithecium formation. The ∆AQP1 mutant conidia were morphologically abnormal and appeared to undergo abnormal germination. The ∆AQP1 mutant and the wild type strain were equally pathogenic, while the mutant produced significantly higher quantities of deoxynivalenol (DON). The ∆AQP1 mutant also exhibited increased resistance to osmotic and oxidative stress as well as cell-wall perturbing agents. Using FgAQP1-GFP and DAPI staining, we found that FgAQP1 is localized to the nuclear membrane in conidia. Importantly, deletion of FgAQP1 increased the severity of conidium autophagy. Taken together, these results suggest that FgAQP1 is involved in hyphal development, stress responses, secondary metabolism, and sexual and asexual reproduction in F. graminearum. Unlike the ∆AQP1 mutant, the ∆AQP2, ∆AQP3, ∆AQP4 and ∆AQP5 mutants had no variable phenotypes.

ABSTRACT. We analyzed meat samples of nine pure lines of rabbit and its 37 hybrid combinations by sequencing and singlestrand conformation polymorphism techniques to explore genetic polymorphisms of all the three exon regions and part of the 5'-regulatory region of the myostatin (MSTN) gene. Thus, we detected a single nucleotide mutation (T→C) on the 476 locus of the 5'-regulatory region, but no mutation sites were detected in the exon areas. The correlation analysis showed that the mutation had some favorable genetic effects, and it resulted in increased liver weight, carcass weight, forelegs weight, back and waist weight, ham weight, and tare weight, whereas it decreased muscle drip loss and cooking loss (P < 0.05). These results suggest that the mutations in the upstream regulatory region of the MSTN gene are beneficial to the rabbit soma development, and the mutations can be used as molecular markers for the selection of the meat quality of rabbits.