The oriental fruit fly, Bactrocera dorsalis (Hendel), is a devastating pest of citrus fruits. After successful mating, adult females insert their eggs into the ripened fruit, resulting in moldy and rotten fruit and causing great economic losses for the citrus industry. In the field, flies initiate copulatory behaviors as twilight approaches, and decreasing light intensity in this period is the normal stimulus for copulation. In this study, ten light intensities ranging from 0–30 000 lux were set to identify the typical intensity that strongly regulates the copulation behavior of B. dorsalis. Three light intensities found to regulate the copulation behavior were then selected to verify their effects on adult male wing fanning and female chemotaxis towards 2,3,5-trimethylpyrazine (TMP). At last, strong light and complete darkness were artificially combined in the lab to verify whether they could prevent copulation to inform behavioral manipulation of oriental flies in the future. The results indicated that adult flies generally initiated copulatory behaviors at low light intensity (<1 000 lux). Stronger light significantly prevented copulation in proportion to intensity, with nearly no copulation events initiated when light intensity was above 20 000 lux. Both male wing fanning and female chemotaxis towards TMP were attenuated as light intensity became stronger. However, at 10 000 lux, males still fanned their wings to a certain extent while TMP completely lost its attractiveness to females. In the darkness, adults did not initiate any sexual behaviors, e.g., copulation, wing fanning, or chemotaxis to TMP. One hour of strong light (10 000 lux) combined with continuous darkness completely prevented mating. These results show that light condition is an essential factor for copulatory behaviors in the oriental fruit fly. Researchers could thus manipulate light conditions artificially or disrupt the molecular target in flies’ light transduction pathway to develop environmentally-friendly techniques to control this pest.
Development and characterization of wheat–Aegilops kotschyi 1Uk(1A) substitution line with positive dough quality parameters
Exploring novel high molecular weight glutenin subunits (HMW-GSs) from wild related species is a strategy to improve wheat processing quality. The objective of the present investigation was to identify the chromosomes of the wheat-alien introgression line N124, derived from the hybridization between Triticum aestivum with Aegilops kotschyi, and characterize the effects on quality-related traits. Fluorescence in situ hybridization karyotypes showed that N124 is a disomic 1Uk(1A) substitution line. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and reversed-phase high-performance liquid chromatography verified N124 expressed two HMW-GSs of the Ae. kotschyi parent. PacBio RNA sequencing and phylogenetic analysis confirmed that the two HMW-GSs were Ukx and Uky. Compared to the wheat parent, the substitution line had no obvious agronomic defects except fewer grains per spike but improved several major quality parameters. It can be served as a donor or bridge material for wheat quality improvement.
Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating fungal disease on small grain cereal crops, because it reduces yield and quality and causes the mycotoxin contamination to the grain. Dynamins and dynamin-related proteins (DRPs) are large GTPase superfamily members, which are typically involved in the budding and division of vesicles in eukaryotic cells, but their roles in Fusarium spp. remain unexplored. Here, we found that FgDnm1, a DRP and homolog to Dnm1 in Saccharomyces cerevisiae, contributes to the normal fungal growth, sexual reproduction and sensitivity to fungicides. In addition, we found FgDnm1 co-localizes with mitochondria and is involved in toxisome formation and deoxynivalenol (DON) production. Several quinone outside inhibitors (QoIs) and succinate dehydrogenase inhibitors (SDHIs) cause fragmentated morphology of mitochondria. Importantly, the deletion of FgDnm1 displays filamentous mitochondria and blocks the mitochondrial fragmentation induced by QoIs and SDHIs. Taken together, our studies uncover the effect of mitochondrial dynamics in fungal normal growth and how such events link to fungicides sensitivity and toxisome formation. Thus, we concluded that altered mitochondrial morphology induced by QoIs and SDHIs depends on FgDnm1.
Plant height is a key plant architectural trait that affects the seed yield, harvest index and lodging resistance in Brassica napus L., although the genetic mechanisms affecting plant height remain unclear. Here, a semi-dwarf mutant, df34, was obtained by ethyl methanesulphonate-induced mutagenesis. Genetic analysis showed that the semi-dwarf phenotype is controlled by one semi-dominant gene, which was located on chromosome C03 using a bulked segregant analysis coupled with whole-genome sequencing, and this gene was named BnaSD.C3. Then BnaSD.C3 was fine-mapped to a 297.35-kb segment of the “Darmor-bzh” genome, but there was no potential candidate gene for the semi-dwarf trait underlying this interval. Furthermore, the interval was aligned to the Zhongshuang 11 reference genome. Finally, combining structural variation analysis, transcriptome sequencing, phytohormone analyses and gene annotation information, BnaC03G0466900ZS and BnaC03G0478900ZS were determined to be the most likely candidate genes affecting the plant height of df34. This study provides a novel major locus for breeding and new insights into the genetic architecture of plant height in B. napus
In yeast, the stress-responsive protein Whi2 interacts with phosphatase Psr1 to form a complex that regulates cell growth, reproduction, infection, and the stress response. However, the roles of Whi2 and Psr1 in Fusarium graminearum remain unclear. In this study, we identified homologous genes of WHI2 and PSR1 in F. graminearum and evaluated their functions by constructing deletion mutants. By comparing the responses of the mutants to different stressors, we found that FgWHI2 and FgPSR1 were involved in responding to osmotic, cell wall and cell membrane stresses, while also affecting the sexual and asexual reproduction in F. graminearum. Our studies demonstrated that FgWHI2 and FgPSR1 regulate the biosynthesis of ergosterol and the transcriptional level of FgCYP51C, which is a CYP51 paralogues unique to Fusarium species. This study also found that the deoxynivalenol (DON) production of FgWHI2 and FgPSR1 deletion mutants was reduced by ≥ 90% and DON production was positively correlated with the transcriptional levels of FgWHI2 and FgPSR1. In addition, we observed that FgWHI2 and FgPSR1 were involved in regulating the sensitivity of F. graminearum to chlorothalonil, fluazinam, azoxystrobin, phenamacril, and oligomycin. This study revealed the existence of cross-resistance between chlorothalonil and fluazinam. chlorothalonil and fluazinam inhibited DON biosynthesis by suppressing the expression of FgWHI2. Interestingly, the subcellular localization of FgWhi2 and FgPsr1 was significantly altered after treatment with chlorothalonil and fluazinam, with increased co-localization. Collectively, these findings indicate that FgWHI2 and FgPSR1 play crucial roles in stress response mechanisms, reproductive processes, secondary metabolite synthesis, and fungicide sensitivity in F. graminearum.