Journal of Agricultural and Food Chemistry

Potato late blight triggered by Phytophthora infestans ((Mont.) de Bary) represents a great food security threat worldwide and is difficult to control. Currently, Bacillus spp. have been considered biocontrol agents to control many fungal diseases. Here, Bacillus subtilis WL-2 was selected as the antifungal strain with the most potential against P. infestans mycelium growth. Additionally, the functional metabolites extracted from WL-2 were identified as IturinA-family cyclic lipopeptides (CLPs) via high-performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI-MS). Analyses using scanning and transmission electron microscopy (SEM and TEM) revealed that IturinA caused a change in the mycelial surface and damage to the internal cell structure, including cell membrane disruption and irregular organelle formation. Moreover, propidium iodide staining and nucleic acid and protein release were detected to clarify the cell membrane damage caused by IturinA. Additionally, IturinA triggered reactive oxygen species (ROS) generation and malondialdehyde (MDA) production. Mitochondrial membrane potential (MMP), mitochondrial respiratory chain complexes activity (MRCCA), respiratory control rate (RCR), and oxidative phosphorylation efficiency (P/O) assays indicated that P. infestans mitochondria affected by IturinA were so seriously damaged that the MMP and MRCCA declined remarkably and that mitochondrial ATP production ability was weakened. Therefore, IturinA induces cell membrane damage, oxidative stress, and dysfunction of mitochondria, resulting in P. infestans hyphal cell death. As such, the results highlight that B. subtilis WL-2 and IturinA have great potential as candidates for inhibiting P. infestans mycelium growth and controlling potato late blight.\n\nIMPORTANCEPotato (Solanum tuberosum L.) is the fourth most common global food crop, and its planting area and yield increase yearly. Notably, in 2015, China initiated a potato staple food conversion strategy, and by 2020, approximately 50% of potatoes will be consumed as a staple food. The plant pathogen fungus Phytophthora infestans ((Mont.) de Bary) is the culprit of potato late blight; however, biological agents rather than chemicals are highly necessary to control this threatening disease. In this study, we discovered an antifungal substance, IturinA, a lipopeptide produced by Bacillus subtilis WL-2. Moreover, our research revealed the actual mechanism of IturinA against P. infestans mycelium growth and clarified the potential of B. subtilis WL-2 and IturinA as a biocontrol agent against P. infestans mycelium growth as well as for controlling the development of late blight in potato cultivation.

The utilization of RNA interference (RNAi) for pest management has garnered global interest. The bioassay results suggested the knockout of PxRdl2 significantly increased the insecticidal activities of the{gamma} -aminobutyric acid receptor (GABAR) targeting compounds (Fipronil, two pyrazoloquinazolines and two isoxazolines), thereby presenting a viable target gene for RNAi-mediated pest control. Consequently, we suggest enhancing the insecticidal activities of GABAR-targeting compounds by knockdown the transcript level of PxRdl2. Furthermore, PxRdl2 dsRNA was expressed in HT115 Escherichia coli to reduce costs and protect dsRNA against degradation. In comparison to in vitro synthesized dsRNA, the recombinant bacteria (ds-B) exhibited superior interference efficiencies and greater stability when exposed to UV irradiation. Collectively, our results provide a new strategy of insecticide spray which combined synergistically with insecticidal activities by suppressing PxRdl2 using ds-B, and may be beneficial for reducing the usage of insecticide and slowing pest resistance.

Postharvest partial dehydration of blueberries can enhance blueberry wine aroma, while the underlying mechanisms remain unclear. In this study, the key odor-active volatiles in blueberry wines fermented from dehydrated blueberries (30% weight loss) were identified via aroma extract dilution analysis. Results showed that increased levels of phenylalanine-derived compounds such as phenylethanol, and terpenes such as linalool and geraniol, primarily led to the enhancement of sweet, floral and fruity aromas of blueberry wines. Postharvest partial dehydration increased the contents of these compounds, which could be linked to the upregulation of VcGOT2 and VcPAR involved in phenylalanine metabolism, and the upregulation of VcDXS, VcHDR and VcTPS involved in terpene biosynthesis. Notably, the upregulated VcTPS encoded a monoterpene synthase responsible for producing linalool. These findings provided insight into the impact of postharvest dehydration on phenylalanine and terpene metabolism in blueberries, offering a reference for improving blueberry wine aroma through postharvest partial dehydration techniques.

Modern fungicides have made significant contributions to crop disease management, but the development of resistant fungal strains has caused their failure in disease control. Therefore, developing fungicides with novel action mechanisms is the most effective measure to manage resistance. Quinofumelin, a novel quinoline fungicide, exhibits exceptional antifungal activity against phytopathogens. However, there is currently no available information on its mechanism of action. Here, we used transcriptome and metabolome analysis to observe a co-enrichment pattern of differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) within pyrimidine biosynthesis pathway (PBP), identifying down-regulation of dihydroorotate dehydrogenase (DHODH). Exogenous uridine monophosphate (UMP), uridine or uracil (metabolites in PBP) successfully restored quinofumelin-induced inhibition of mycelial growth in Fusarium graminearum and Fusarium asiaticum. Additionally, the deletion of FgDHODHII was determined to be lethal; however, mycelial growth of {Delta}FgDHODHII mutants could be restored by adding UMP, uridine or uracil. These findings indicate that the deficiencies in FgDHODHII are functionally equivalent to complete inhibition of its activity by quinofumelin. Finally, molecular docking, surface plasmon resonance (SPR) and microscale thermophoresis (MST) results strongly support the precise interaction between quinofumelin and FgDHODHII. Collectively, these findings provide compelling evidence for the involvement of de novo uracil biosynthesis as mechanism of action for quinofumelin while identifying FgDHODHII as its specific target.

Effective colonization on plant roots is a prerequisite for plant growth promoting rhizobacterias (PGPR) to exert beneficial activities. Light is essential for plant growth, development and stress response. However, how light modulates root colonization of PGPR remains unclear. Here, we found that high red/far red(R/FR) light promoted and low R/FR light inhibited the colonization and growth enhancement of Serratia plymuthica A21-4 on tomato. Non-targeted metabolomic analysis of root exudates collected from different R/FR ratio treated tomato seedlings with A21-4 inoculation by ultra performance liquid chromatography-tandem mass spectrometry showed that 64 primary metabolites including amino acids, sugars and organic acids in high R/FR light-grown plants significantly increased compared with those determined for low R/FR light-grown plants. Among them, 7 amino acids, 1 organic acid and 1 sugar obviously induced the chemotaxis and biofilm formation of A21-4 compared to the control. Furthermore, exogenous addition of five artificial root exudate compontents (leucine, methionine, glutamine, 6-aminocaproic acid and melezitose) regained and further increased the colonization and growth promoting ability of A21-4 in tomato under low R/FR light and high R/FR light, respectively, indicating their involvement in high R/FR light-regulated the interaction of tomato root and A21-4. Taken together, our results, for the first time, clearly demonstrate that high R/FR light-induced root exudates play a key role in chemotaxis, biofilm formation and root colonization of A21-4. This study provides new insights into the interactions of plant-PGPR under different light conditions and can help promote the combined application of light supplementation and PGPR to facilitate crop growth and health in green agricultural production.

The European honey bee, Apis mellifera, serves as the principle managed pollinator species globally. In recent decades, honey bee populations have been facing serious health threats from combined biotic and abiotic stressors, including diseases, limited nutrition, and agrochemical exposure. Understanding the molecular mechanisms underlying xenobiotic adaptation of A. mellifera is critical, considering its extensive exposure to phytochemicals and agrochemicals present in flowers, propolis, hives, and the environment. In this study, we conducted a comprehensive structural and functional characterization of AmGSTD1, a delta class glutathione S-transferase (GST) enzyme, to unravel its roles in agrochemical detoxification and antioxidative stress responses. Significantly, we determined the 3D structure of a honey bee GST using protein crystallography for the first time, providing new insights into its molecular structure. Our investigations revealed that AmGSTD1 efficiently metabolizes model substrates, including 1-chloro-2,4-dinitrobenzene (CDNB), p-nitrophenyl acetate (PNA), phenylethyl isothiocyanate (PEITC), propyl isothiocyanate (PITC), and the oxidation byproduct 4-hydroxynonenal (4-HNE). Moreover, we discovered that AmGSTD1 exhibits binding affinity with the fluorophore 8-Anilinonaphthalene-1-sulfonic acid (ANS), which can be inhibited with various herbicides, fungicides, insecticides, and their metabolites. These findings highlight the potential contribution of AmGSTD1 in safeguarding honey bee health against various agrochemicals and their metabolites, while also mitigating oxidative stress resulting from exposure to these substances.

Soapberry (Sapindus mukorossi Gaertn.) pericarps are rich in valuable bioactive triterpenoid saponins. However, the saponin content dynamics and the molecular regulatory network of saponin biosynthesis in soapberry pericarps remain largely unclear. Here, we performed combined metabolite profiling and transcriptome analysis to identify saponin accumulation kinetic patterns, investigate gene networks, and characterize key candidate genes and transcription factors involved in saponin biosynthesis in soapberry pericarps. A total of 54 saponins were tentatively identified, including 25 that were differentially accumulated. Furthermore, 49 genes putatively involved in sapogenin backbone biosynthesis and some candidate genes assumed to be responsible for the backbone modification, including 41 cytochrome P450s and 45 glycosyltransferases, were identified. Saponin-specific clusters/modules were identified by Mfuzz clustering and weighted gene co-expression network analysis, and one TF-gene regulatory network underlying saponin biosynthesis was proposed. The results of yeast one-hybrid assay and electrophoretic mobility shift assay suggested that SmbHLH2, SmTCP4, and SmWRKY27 may play important roles in the triterpenoid saponin biosynthesis by directly regulating the transcription of SmCYP71D-3 in soapberry pericarp. Overall, these findings provide valuable information for understanding the molecular regulatory mechanism of saponin biosynthesis, enriching the gene resources, and guiding further research on triterpenoid saponin accumulation in soapberry pericarps. One-sentence summaryCombining metabolome and transcriptome analysis to identify saponin kinetic patterns, gene networks, and key candidate genes and transcription factors involved in saponin biosynthesis of soapberry.

Long-term monoculture of ginger triggers Fusarium wilt, a disease caused by Fusarium oxysporum f. sp. niveum (Foz). However, the role of autotoxins in promoting pathogen growth remains unclear. Four representative autotoxins, syringic acid, coumarin, ferulic acid and 7-Hydrooxycoumarin were selected to investigate their allelopathic effects on the growth, reproduction, and virulence-associated traits of Foz. The responses of Foz to these compounds exhibited notable variations, which may be attributed to the structural differences among the autotoxins. The autotoxic compounds differentially enhanced the key pathogenic traits of Foz. Syringic acid was the most effective stimulant of mycelial growth and cell wall-degrading enzymes activity, concurrently boosting mycotoxin production via upregulating FUB3 gene expression. Ferulic acid was the most potent promoter of sporulation and biomass accumulation, whereas 7-Hydroxycoumarin most effectively stimulated conidial germination. Notably, coumarin suppressed mycelial growth but strongly induced mycotoxin synthesis in Foz. These results provide mechanistic insights into how autotoxins in ginger monoculture systems promote Fusarium wilt.

Schisandrin B (Sch-B) is a predominant bioactive lignan in the fruit of a traditional Chinese medicinal plant Schisandra Chinensis with widely reported anti-cancer properties. Using a xenograft mouse model of colorectal cancer (CRC), we showed potent anti-tumor effects of Sch-B and synergistic effects when co-treated with the chemotherapy drug, fluorouracil (5-FU). To explore the underlying anti-tumor mechanism of Sch-B, we first compared the bioavailability, metabolism and tissue distribution of Sch-B and its metabolites among healthy and tumor-bearing mice. To understand the drug-phytochemical interactions associated with the synergy between Sch-B and 5-FU, we examined their reciprocal influence on drug metabolism, tissue distribution, and multidrug resistance (MDR) gene expression in tumor-bearing mice. Using a targeted metabolomics approach, three Sch-B metabolites and two bioactive 5-FU metabolites were quantified and found to reach tumor tissue. Generally, Sch-B metabolites were present at higher levels in tumor-bearing than healthy mice, whereas 5-FU metabolite accumulation was remarkably higher in the co-treatment than 5-FU alone group. Moreover, MDR genes were significantly downregulated upon co-treatment, demonstrating the capacity of Sch-B to reverse MDR in chemotherapy. This study showed that Sch-B may serve as a promising adjuvant to chemotherapy drugs via favorably modulating drug metabolism and bioavailability, and attenuating MDR.

Eucommia ulmoides Oliver Ziye has unique purple-red leaves, which contain a variety of flavonoids, so it has high ornamental and medicinal value. However, the categories of flavonoids and molecular mechanism of specific accumulation of flavonoids in Ziye leaves is still unclear. Here, differences in metabolic level, gene expression level, chromatin accessibility and cis-regulatory elements were compared between Ziye and Huazhong 1 with green leaf color by metabolome profiling, RNA-seq, and ATAC-seq. A total of 205 flavonoids were identified from these two varieties using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). The accumulation of most delphinidin, cyaniding, quercetin, myricetin, and isorhamnetin derivatives peaked in old leaves of Ziye. Single-molecule long-read sequencing indicated that genes in the phenylpropanoid biosynthesis and flavonoid biosynthetic pathway, as well as many transcription factors including MYB, ERF, and WRKY were highly expressed in Ziye leaves. ATAC-seq revealed the presence of cell preferentially enriched peaks, which annotated to 6114 genes. Analysis of the genomic regions preferentially accessible in each cell type identified hundreds of overrepresented TF-binding motifs, highlighting sets of TFs such as MYB, ERF, and WRKY that are probably important for color formation of Ziye cell. Interestingly, the TFs within each of these cell type-enriched sets also showed evidence of extensively co-regulating each other. Our work demonstrated how chromatin accessibility and TF expression level influenced the expression of flavonoid biosynthesis associated genes, resulted in flavonoids accumulation in Ziye leaf. Our results could lay a foundation for further studies of gene expression and functional genomics in E. ulmoides.

Trichoderma species are recognized for their robust biocontrol capacity, primarily due to the production of peptaibols, potent secondary metabolites that exhibit antibacterial properties, induce cell apoptosis, and enhance plant disease resistance. To elucidate the regulatory mechanism of peptaibol synthesis, we investigated the role of a transcription regulator gene TRG1 (designated as TLTRG1), which we identified within a non-ribosomal peptide synthetase (NRPS) gene cluster of T. longibrachiatum SMF2. We successfully created a{Delta} TRG1 gene knockout mutantusing homologous recombination. Phenotypic analysis indicated that the{Delta} TRG1 mutant maintained wild-type growth rate, colony morphology, and spore production. However,{Delta} TRG1 exhibited a significantly reduced inhibition rate against the plant pathogen Botrytis cinerea and a lower efficacy in controlling gray mold on detached rose leaves. High-performance liquid chromatography (HPLC) analysis provided direct molecular evidence, showing that peptaibol production in the mutant was 2.5 times lower than that of the wild-type strain. These findings conclusively establish that TRG1 functions as a key positive transcriptional regulator essential for high-yield peptaibol biosynthesis by modulating NRPS gene expression. This gene represents a critical molecular target for bioengineering strategies aimed at enhancing the biocontrol efficacy of Trichoderma strains. The Importance sectionTrichoderma species are known to produce peptaibols, which exhibit antibacterial properties, induce cell apoptosis, and enhance plant disease resistance. However, the mechanisms underlying the biosynthesis and regulation of peptaibols remain unclear. In this study, we investigated the role of a transcription regulator gene located within a non-ribosomal peptide synthetase (NRPS) gene cluster of T. longibrachiatum SMF2, which we designated as TLTRG1 (TRG1). Phenotypic analysis indicated the inhibition rate of {Delta}TRG1 against Botrytis cinerea and its effectiveness in controlling gray mold were significantly reduced compared to the WT strain. High-performance liquid chromatography (HPLC) analysis revealed that the production of peptaibols in the mutant was significantly decreased. These findings suggest that the TRG1 gene may play a crucial role in regulating the expression of NRPS genes, thereby affecting the biosynthesis of peptaibols. Therefore, it can be concluded that the gene TRG1 is a molecular target for bioengineering strains with enhanced biocontrol efficacy.

Isoprothiolane (IPT) resistance has emerged in Magnaporthe oryzae, due to the long-term usage of IPT to control rice blast in China, yet the mechanisms of the resistance remain largely unknown. Through IPT adaptation on PDA medium, we obtained a variety of IPT-resistant mutants. Based on their EC50 values to IPT, the resistant mutants were mainly divided into three distinct categories i.e., low resistance (LR, 6.5 [&le;] EC50 < 13.0 g/mL), moderate resistance 1 (MR-1, 13.0 [&le;] EC50 < 25.0 g/mL), and moderate resistance 2 (MR-2, 25.0 [&le;] EC50 < 35.0 g/mL). Molecular analysis of MoIRR (Magnaporthe oryzae isoprothiolane resistance related) gene demonstrated that it was associated only with the moderate resistance in MR-2 mutants, indicating that other mechanisms were associated with resistance in LR and MR-1 mutants. In this study, we mainly focused on the characterization of low resistance to IPT in M. oryzae. Mycelial growth and conidial germination were significantly reduced, indicating fitness penalties in LR mutants. Based on the differences of whole genome sequences between parental isolate and LR mutants, we identified a conserved MoVelB gene, encoding the velvet family transcription factor, and genetic transformation of wild type isolate verified that MoVelB gene was associated with the low resistance. Based on molecular analysis, we further demonstrated that the velvet family proteins VelB and VeA were indispensable for IPT toxicity and the deformation of the LaeA-VeA-VelB heterotrimer played a vital role for the low IPT-resistance in M. oryzae, most likely through the down-regulation of the secondary metabolism-related genes or CYP450 genes to reduce the toxicity of IPT. Author summaryIsoprothiolane (IPT) resistance has emerged in Magnaporthe oryzae, due to the long-term usage of IPT to control rice blast in China, yet the mechanisms of the resistance remain largely unknown. Here, we explored the mechanisms of low IPT resistance in M. oryzae. Combining the whole genome sequencing and genetic transformation, we identified a conserved MoVelB gene, encoding the velvet family transcription factor to be a determinant for IPT toxicity. We further demonstrated that the deformation of the LaeA-VeA-VelB heterotrimer conferred the low IPT-resistance in M. oryzae, most likely through down-regulating the secondary metabolism-related genes or CYP450 genes to reduce the toxicity of IPT. This study improved our understanding of the resistance mechanism as well as the mode of action of IPT which will be helpful for making suitable strategies to manage the emerging resistance of IPT in M. oryzae.

The Colorado potato beetle (CPB) is a prominent insect pest of potatoes, tomatoes and eggplants all over the world, however, the management of CPB remains a challenging task for more than one hundred years. We have successfully developed bacteria-expressed dsRNA-mediated feeding RNA interference (RNAi) approach in our previous study. A critical step towards field management of CPB via feeding RNAi is to identify effective and environmentally safe target genes. NADPH-Cytochrome P450 reductase (CPR) plays a central role in cytochrome P450 action. The full length Leptinotarsa decemlineata CPR (LdCPR) cDNA was isolated from an imidacloprid resistant population. The LdCPR gene was ubiquitously expressed in all stages tested but showed an increase in expression during the early stage of embryonic development. The bacteria-expressed dsRNA-mediated feeding RNAi of LdCPR in adults caused systemic knock down expression of the gene coding for LdCPR in both adults and their eggs. Suppression of LdCPR expression increased susceptibility of imidacloprid in resistant beetles, as well as a significant decrease of fecundity in female beetles (29% less eggs/day) and the hatching rate (47%) of their eggs. These data suggest that LdCPR plays important roles in insecticide detoxification and biosynthetic pathways of endogenous compounds and may serve as an essential target to control CPB. HIGHLIGHTSO_LIHigh expression of LdCPR was observed in the egg stage. C_LIO_LISilencing of LdCPR reduced the CPR enzymatic activities. C_LIO_LILdCPR knockdown increased imidacloprid susceptibility. C_LIO_LILdCPR knockdown decreased the fecundity and enhanced embryonic lethality. C_LI

Plants produce diverse secondary compounds as natural protection against microbial and insect attack. Most of these compounds, including bitters and acids, are sensed by insect gustatory receptors (Grs). Acids are potentially toxic to insects, but there are few reports on sour compounds as ligands of insect Grs. Here, using two different heterologous expression systems, the insect Sf9 cell line and the mammalian HEK293T cell line, we started from crude extracts of rice (Oryza sativa) and successfully identified oxalic acid (OA) as a ligand of NlGr23a, a Gr in the brown planthopper Nilaparvata lugens. The antifeedant effect of OA on the brown planthopper was dose dependent, and NlGr23a is essential for OAs antifeedant activity in both artificial diets and rice plants. NlGr23a is also indispensable for tarsal OA sensing. To our knowledge, OA is the first identified ligand starting from plant crude extracts and the first known strong acid for insect Grs. These findings on rice-planthopper interactions will be of broad interest for pest control in agriculture and also for better understanding of how insects select host plants. Research organismNilaparvata lugens

Bacillus velezensis, a prominent member of plant growth-promoting bacteria, effectively suppresses pathogens and promotes plant growth. Despite its well-recognized efficacy, the intricate molecular mechanisms of its growth-promoting attributes remain largely unexplored. In this study, a commercial biopesticide B. velezensis 9912 significantly enhanced leaf photosynthesis and improved rice root development in the field experiment. And then, a rigorous hydroponic experiment was performed to investigate its underlying mechanism in plant growth promotion. High-throughput sequencing and bioinformatics analysis revealed 2,938 rice genes and 30 miRNAs responsive to strain 9912. Notably, differentially expressed genes encompassed key transcription factors like ERF, WRKY, and AP2. Remarkably, auxin-and ethylene-related genes were up-regulation significantly at day 1 and pectinesterase-related genes were up-regulation considerably at day 3, which revealed an unusual growth mechanism for strain 9912 to promote rice root development. In addition, DNA replication, cell cycle, cell division, and cytoskeleton organization were significantly enriched in GO and KEGG pathways. Biosynthetic pathways of secondary metabolites, such as carotenoid, lipid, diterpenoid, and brassinosteroid were also significantly enriched. An integrated analysis of the transcriptome and miRNAome identified several miRNA-mRNA regulatory networks, including miR166-Os08g14940, miR396-Os07g9320, miR529-Os12g31540, and miR6249-Os05g07880, which are involved in the process of growth promotion. In conclusion, our investigation offers insightful thoughts into the dynamic responses of rice genes and miRNAs to B. velezensis 9912, unveiling plant hormone modulation and potential miRNA-mRNA regulatory networks that are imperative in the growth promotion mechanism.

Halophytes are promising sources of bioactive phenolic compounds for the food and pharmaceutical industries. However, their phenolic composition is influenced by environmental conditions, and the in vivo antioxidant activity of their phytochemicals is largely unknown. We evaluated the antioxidant capacity of phenolic-rich methanolic extracts from the edible halophyte Crithmum maritimum, grown in wild and greenhouse conditions. Additionally, their in vivo antioxidant capacity was analyzed for the first time using the model Caenorhabditis elegans. Wild plant extracts showed higher phenolic content and diversity, and in vitro antioxidant activity. Both extracts enhanced oxidative stress resistance and increased nematode survival rates, albeit to varying extents, and increased reactive oxygen species production in nematodes, without affecting their lifespan, suggesting a hormetic mechanism. Although no neuroprotective effects were observed in models of neurodegenerative diseases, these findings highlight the potential of C. maritimum as a valuable source of phenolics with antioxidant properties for the food industry.

Fusarium asiaticum is a destructive phytopathogenic fungus that causes Fusarium head blight of wheat (FHB), leading to serious yield and economic losses to cereal crops worldwide. Our previous studies indicated that target-site mutations (K216R/E, S217P/L, or E420K/G/D) of Type I myosin FaMyo5 conferred high resistance to phenamacril. Here, we first constructed a sensitive strain H1S and point mutation resistant strains HA, HC and H1R. Then we conducted comparative transcriptome analysis of these strains in F. asiaticum after 1 g{middle dot}mL-1 and 10 g{middle dot}mL-1 phenamacril treatment. Results indicated that 2135 genes were differentially expressed (DEGs) among the sensitive and resistant strains. Among them, the DEGs encoding ammonium transporter MEP1/MEP2, nitrate reductase, copper amine oxidase 1, 4-aminobutyrate aminotransferase, amino-acid permease inda1, succinate-semialdehyde dehydrogenase, 2, 3-dihydroxybenzoic acid decarboxylase, etc., were significantly up-regulated in all the phenamacril-resistant strains. Compared to the control group, a total of 1778 and 2097 DEGs were identified in these strains after 1 g{middle dot}mL-1 and 10 g{middle dot}mL-1 phenamacril treatment, respectively. These DEGs involved in 4-aminobutyrate aminotransferase, chitin synthase 1, multiprotein-bridging factor 1, transcriptional regulatory protein pro-1, amino-acid permease inda1, ATP-dependent RNA helicase DED, acetyl-coenzyme A synthetase, sarcoplasmic/endoplasmic reticulum calcium ATPase 2, etc., showed significantly down-regulated expression in phenamacril-sensitive strain but not in resistant strains after phenamacril treatment. In addition, cyanide hydratase, mating-type protein MAT-1, putative purine nucleoside permease, plasma membrane protein yro2, etc., showed significantly co-down-regulated expression in all the strains after phenamacril treatment. Taken together, This study provide deep insights into the resistance regulation mechanism and inhibitory effect of fungicide phenamacril and these new annotated proteins or enzymes are worth for the discovery of new fungicide targets. Author summaryFungicide phenamacril resistance occur in F. asiaticum and the resistance regulation mechanis are systematic and complex. Here, we conducted comparative transcriptome analysis of a sensitive strain H1S and point mutation resistant strains HA, HC and H1R in F. asiaticum after 1 g{middle dot}mL-1 and 10 g{middle dot}mL-1 phenamacril treatment. Among these annotated proteins or enzymes, amino-acid permease inda1, 1, 4-aminobutyrate aminotransferase, chitin synthase 1, multiprotein-bridging factor 1, ATP-dependent RNA helicase DED, acetyl-coenzyme A synthetase, sarcoplasmic/endoplasmic reticulum calcium ATPase 2, cyanide hydratase, mating-type protein MAT-1, putative purine nucleoside permease, plasma membrane protein yro2, etc., were involved in the resistance regulation mechanism and inhibitory effect of fungicide phenamacril. Our paper provides a reference basis for the study of drug resistance in other microorganisms. In addition, the relevant proteins or enzymes annotated in our study also have reference value for the discovery of new fungicide targets.

The high content of cyanogenic glycosides (CG) in cassava storage tubers seriously affects human food safety. CG play crucial roles in plant growth and development and can protect cassava leaves from being masticated by herbivorous predators. Nevertheless, the regulatory mechanism of CG biosynthesis, which results in a low CG content in storage tubers and high CG content in leaves, remains poorly understood. Here, yeast one-hybrid assay was performed using a mixed cDNA library of cassava storage roots and leaves as prey and the promoter of MeCYP79D2 as bait. MeCYP79D2, a cytochrome P450 protein, is the rate-limiting enzyme for CG synthesis in cassava. From this information, a candidate regulator of MeCYP79D2, that is, transcription factor MePHD1.2, was selected. MePHD1.2, which is located in the nucleus and exhibits a transcription inhibitory activity, can directly bind to PD2 segment in the promoter of MeCYP79D2, which results in its repressed expression. In cassava, the transcriptional activity of MeCYP79D2 was considerably enhanced in mephd1.2 lines, which caused an increase in the contents of linamarin and lotaustralin. Our findings unveil a novel regulatory module governing CG biosynthesis, wherein mutation of MePHD1.2 attenuates its transcription inhibition on MeCYP79D2 and boosts CGs biosynthesis in cassava.

Transcription factor aryl hydrocarbon receptor (AhR) can enhance insect resistance to insecticides by regulating the detoxification metabolic network. Our previous studies have confirmed that overexpression of cytochrome P450 monooxygenases (P450s) and glutathione S-transferases (GSTs) are both involved in lambda-cyhalothrin resistance in Cydia pomonella. In this study, we report that AhR regulates GSTs thus conferring lambda-cyhalothrin resistance in C. pomonella. Spatiotemporal expression patterns indicated that AhR gene of C. pomonella (CpAhR) was highly expressed in the Malpighian tubules of larvae. Moreover, the expression of CpAhR was induced by lambda-cyhalothrin exposure and was up-regulated in a lambda-cyhalothrin-resistant population. RNA interference (RNAi) of the expression of CpAhR could effectively decrease the relative expression level of CpGSTe3 and enzyme activity of GSTs, but not P450s, further reducing the tolerance of larvae to lambda-cyhalothrin. Furthermore, {beta}-naphthoflavone (BNF), a novel agonist of AhR, can effectively increase the expression of CpAhR and the activity of the GSTs enzyme, resulting in the enhancement of larvae tolerance to lambda-cyhalothrin. These results demonstrate that lambda-cyhalothrin exposure can effectively activate the expression of CpAhR and increase GSTs enzyme thus leading to the development of resistance to lambda-cyhalothrin, which enriches the theory of insecticide resistance regulation in C. pomonella.

Oregano is an important economic plant which has valuable medicinal and aromatic properties. Oregano essential oil, containing carvacrol and thymol, is a preferred material to replace antibiotics in feed additives. Glandular secretory trichome (GST) density has positively correlated with the production of these compounds. Here, two haplotype-resolved genomes were assembled and annotated which contained 15 chromosomes with the total length of 606.75 and 612.74 Mb, respectively. Oregano had experienced two whole-genome duplications corresponding to the divergence [~]5.120/4.564 and [~]66.857/69.923 Mya, respectively. Many transcription factors and genes were found related to GSTs formation mechanism such as R2R3-MYB- and HD-ZIP IV-encoding genes. 2,669,410 SNPs, 569,093 InDels, 14,839 DUPs, 110 INVs, 3,976 TRANSs, and 1,426 CNVs were detected among two haplotype-resolved genomes. Two high density genetic linkage maps consisted of 15 LGs and spanned 2,279.28 and 2,322.83 cM, respectively. GADS, GABS, and GTS of F2 segregating populations showed obvious superparental dominance. One/one, one/one, and two/four QTLs for GADS, GABS, and GTS were independently mapped on two genetic maps, respectively. Five candidate genes showed extreme difference in two bulked segregant pools. Our study not only provides significant insight into the GSTs formation mechnism, but also will facilitate molecular breeding in oregano. One Sentence SummaryOregano essential oil is a preferred material to replace antibiotics which will use to study the glandular secretory trichome formation mechanism and analyze the source of essential oil.