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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.

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.

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Dormancy regulation is the basis of the sustainable development of the lily industry. Therefore, basic research on lily dormancy is crucial for the innovation of lily cultivation and breeding. Previous studies revealed that dormancy release largely depends on abscisic acid (ABA) degradation. However, the key genes and potential regulatory network remain unclear. We used exogenous ABA and ABA inhibitors to elucidate the effect of ABA on lily dormancy. Based on the results of weighted gene coexpression network analysis (WGCNA), the hub gene LdXERICO was identified in modules highly related to endogenous ABA, and a large number of coexpressed genes were identified. LdXERICO was induced by exogenous ABA and expressed at higher levels in tissues with vigorous physiological activity. Silencing LdXERICO increased the low-temperature sensitivity of bulblets and accelerated bulblet sprouting. LdXERICO rescued the ABA insensitivity of xerico mutants during seed germination in Arabidopsis, suggesting that it promotes seed dormancy and supporting overexpression studies on lily bulblets. The significant increase in ABA levels in transgenic Arabidopsis expressing LdXERICO indicated that LdXERICO played a role by promoting ABA synthesis. We generated three transgenic lines by overexpressing LdICE1 in Arabidopsis thaliana and showed that in contrast to LdXERICO, LdICE1 positively regulated dormancy release. Finally, qRT–PCR confirmed that LdXERICO was epistatic to LdICE1 for dormancy release. We propose that LdXERICO, an essential gene in dormancy regulation through the ABA-related pathway, has a complex regulatory network involving temperature signals. This study provides a theoretical basis for further exploring the mechanism of bulb dormancy release.

Background：Regulation and control of bulb dormancy are critical for ensuring annual production and high-level cultivation of lily. Application of low temperatures is the most effective method for breaking lily bulb dormancy, but the molecular regulatory mechanism underlying this response is unclear. Results：Herein, targeted metabolome and transcriptome analyses were performed with buds of Lilium davidii var. unicolor bulbs stored for 0, 50 and 100 days at 4°C. Dormancy release mainly depended on the accumulation of GA4 and GA7, which are synthesized by the "non13-hydroxylation" pathway, rather than GA3, and ABA was degraded in the process. The contents of nonbioactive GA9, GA15 and GA24, the precursors of GA4 synthesis, increased with bulb dormancy release. Altogether, 113,252 unique transcripts were de novo assembled through high-throughput transcriptome sequences, and 639 genes were continuously differentially expressed. Enrichment analysis showed that the carbohydrate metabolism and hormone metabolism pathways play major roles in dormancy release. Energy sources during carbohydrate metabolism mainly depend on glycolysis and the PPP pathway rather than on the TCA cycle. Association analysis of the transcriptome and target metabolome showed that genes related to ABA, GA, starch and sucrose metabolism and some TF families, such as MYB, WRKY, NAC and TCP, involved in dormancy release were highly correlated with the target metabolome. Coexpression analysis further confirmed that ABI5, PYL8, PYL4 and PP2C, vital ABA signaling elements, regulated GA3ox and GA20ox in the GA4 biosynthesis pathway. The TFs WRKY32, WRKY71, MYB, DAM14, NAC8, ICE1, bHLH93 and TCP15 also participated in the ABA/GA4 regulatory network, and ICE1 may be the key factor linking temperature signals and hormone metabolism. Conclusions：These results will help to reveal the bulb dormancy molecular mechanism and to develop new strategies for high-quality bulb production.

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