C-type lectins (CTLs) are proteins with carbohydrate-recognition domains. These macromolecules interact with pathogen components, thereby playing important roles in the immune system. Current studies indicate that silkworm CTLs are involved in Bombyx mori nucleopolyhedrovirus (BmNPV) infection. Nevertheless, the molecular mechanisms through which these CTLs affect viral infection remain unclear. In this study, B. mori C-type lectin 16 (BmCTL16) was identified in the silkworm. Its expression was significantly downregulated upon BmNPV infection. Functional assays showed that BmCTL16 overexpression suppressed BmNPV proliferation, whereas its knockdown enhanced BmNPV proliferation. Protein-protein interaction assays confirmed that BmCTL16 interacts with BmNPV protein Bm9 in the cytoplasm. Notably, BmCTL16 promoted the degradation of Bm9 via the ubiquitin-proteasome system. Knockdown of Bm9 by siRNA significantly reduced BmNPV proliferation, confirming that Bm9 is the key target for BmCTL16 to exert its antiviral function. Collectively, this study reveals a novel CTL-mediated antiviral mechanism. BmCTL16 interacts with Bm9 and promotes its ubiquitin-proteasome degradation, thereby inhibiting viral proliferation. Furthermore, BmNPV evades this host defense by downregulating BmCTL16 expression. These findings enhance our understanding of silkworm CTL-mediated antiviral defense and offer novel perspectives on host-virus interactions in B. mori.

In most species, oocytes are arrested at the prophase or metaphase of meiosis I and require sperm-derived or external stimuli to resume meiosis. Maturation-promoting factor (MPF) is an oocyte maturation factor composing the catalytic subunit Cdc2 and the regulatory subunit CycB that can restart stalled meiosis. In this study, we demonstrated that MPF activity affected parthenogenesis induction in the model lepidopteran insect Bombyx mori using activator and inhibitor interference. We found that the upregulation of MPF activity significantly increased the parthenogenesis induction rate, whereas downregulation significantly reduced it. Furthermore, the inhibition of MPF activity also led to a delay in embryonic development. Given its evolutionary conservation, MPF emerges as a potential universal target for manipulating reproductive outcomes, offering broad applications in genetics and selective breeding.

Sperm deliver male genomic DNA to the ovum, playing a pivotal role in sexual reproduction across the animal kingdom. The molecular regulation of sperm morphogenesis has consequently become a focal point of genetic research, with dual implications for both reproductive medicine and sustainable agriculture. Here, we characterize the functional role of the testis-specific serine/threonine protein kinase-like (TSSKL) gene in the model lepidopteran insect Bombyx mori and the globally destructive crop pest Plutella xylostella. RNA-seq and qPCR analyses revealed TSSKL's testis-specific expression pattern. Using CRISPR/Cas9-mediated mutagenesis, we demonstrate that TSSKL knockout induces complete male sterility, while female fertility remains unaffected compared to wild-type. Fluorescence microscopy and ultrastructural analyses revealed that TSSKL deletion leads to severe morphological defects in both eupyrene and apyrene sperm, accompanied by impaired mitochondrial dynamics and aberrant autophagy. Comparative transcriptome and functional analyses linked these phenotypes to dysregulated energy metabolism pathways. Crucially, this sterility phenotype is conserved in P. xylostella, recapitulating the findings in B. mori. Our study demonstrates that TSSKL is crucial for male fertility, coordinating both structural and metabolic aspects of sperm development. Beyond advancing fundamental knowledge of insect reproductive biology, this work also identifies TSSKL as an ideal target for lepidopteran pest control through precision sterility induction.

Lipid metabolism serves as the primary energy source for organisms. Silkworm eggs for spring use are divided into two types: autumn-produced eggs for next spring rearing (AS) and spring-produced eggs for next spring rearing (SS). Production practice revealed significant differences in hatching rates between these two types of silkworm production strain QiufengA. In this study, we identified differentially expressed genes (DEGs) primarily enriched in energy metabolism pathways. In particular, the PPARs are involved in energy regulation through lipid metabolism. Furthermore, both AS and SS contained the same eight long-chain fatty acids but in different amounts. Interference with PPARs activity in silkworm eggs disrupted the expression of key genes in this pathway, resulting in a significant decrease in hatching rate. Additionally, knockdown of the pathway key gene BmPlin4 led to the reduction in lipid droplets. In conclusion, PPARs regulates the hatching rate of silkworms mainly by affecting lipid metabolism. This study proved the importance of PPARs for hatching and identifies them as potential target genes for population control.

Protein kinase A (PKA), commonly referred to as cAMP-dependent protein kinase, exists as a heterotetramer composed of two catalytic (C) and regulatory subunits (R). This versatile kinase exhibits regulatory functions in various biological processes including growth, division, and differentiation. Although PKA is well established as a master regulator of oocyte maturation across species, its functional role in insect parthenogenesis has remained enigmatic. Here, we systematically investigated the regulatory effect of PKA in the induction of parthenogenesis in model lepidopteran Bombyx mori. Our findings demonstrated an inverse correlation between PKA activity and parthenogenetic induction efficiency in silkworms. Notably, PKA activation resulted in delayed embryonic development, whereas PKA-C1 knockdown disrupted normal cell cycle progression. These results indicated that maintaining appropriate PKA activity is essential for ensuring proper cell division process, especially in the successful induction of silkworm parthenogenesis. The evolutionary conservation of PKA across species, coupled with its critical regulatory role in parthenogenesis, positions this kinase as a promising molecular target for breeding design. Our findings establish a foundation for developing silkworm strains with enhanced parthenogenetic capacity through PKA modulation, thereby facilitating the preservation of elite production traits. These results provide novel mechanistic insights into parthenogenesis while demonstrating the potential application of PKA regulation in both genetic studies and breeding programs.

Cyclin-dependent protein kinase 2 (Cdk2), an important member of the serine/threonine-specific protein kinase family, plays a critical regulatory role in biological processes. Previous studies have demonstrated that Cdk2 is involved in the arrest and resumption of meiosis in mammalian oocytes. In this study, we explored the function of Cdk2 through parthenogenetic lines (PLs) and corresponding amphigonic lines (ALs) in a model lepidopteran insect silkworm, Bombyx mori L. Our findings revealed a positive correlation between Cdk2 activity and the parthenogenesis induction rate. The pharmacological inhibition of Cdk2 using the specific inhibitor AUZ454 not only significantly reduced the parthenogenesis induction rate but also caused developmental delays in embryos. These results demonstrate that Cdk2 is essential for parthenogenesis success and is a potential target gene for biological reproductive regulation.

Silkworm (Bombyx mori) is an economically significant insect that produces silk and makes important contributions to the development of silk-producing countries. The genetic diversity and unique adaptive traits of silkworm germplasm resources form the foundation for breeding efforts. In various geographical regions, silkworm have developed distinct traits through long-term adaptive selection. In this study, we focused on identifying and evaluating representative silkworm germplasm resources from both China and Uzbekistan. We discovered notable differences in the morphology and production traits of local silkworm strains, likely influenced by differing geographical environments. It is also possible that China has a long history of silkworm rearing and after a long time of breeding selection, the diversity of silkworm morphology is less than that of Uzbekistan, but the production characteristics are more suitable for silk utilization. Phylogenetic analysis based on genomic comparisons revealed that Uzbekistan’s local silkworm strains are positioned between China’s local and improved strains. This suggests that Uzbekistan silkworms primarily originated from China. The further analysis of genetic diversity and strain differentiation highlights the unique differences of each country’s silkworms, especially in terms of genetic diversity on chromosome 1 (sex chromosome). By identifying and evaluating these germplasm resources and linking them to unique advantageous traits, it provides a scientific basis for improving cocoon silk quality and optimizing sericulture productivity.

Visible light-induced photocrosslinking techniques have attracted significant attention for their flexibility, controllability, safety, and energy conservation, especially in tissue engineering and biofabrication, compared to UV photocrosslinking. Despite these advantages, current photoinitiators are constrained by various challenges, including inadequate photoinitiation efficiency, low biocompatibility, poor water solubility, and limited compatibility with diverse crosslinking systems. Here, a water-soluble derivative of riboflavin, flavin mononucleotide (FMN-), was used to assess its potential as an initiator in multiple-photocrosslinking systems, including radical photopolymerization, dityrosine, and ditryptophan coupling crosslinking, under blue light irradiation. Blue light irradiation facilitated an efficient electron transfer reaction between FMN- and persulfate, owing to their suitable spectral compatibility and photoactivity. The resulting oxidizing free radicals and excited triplet state of FMN- served as initiating active species for the multiple-photocrosslinking reactions. The combination of FMN- and potassium persulfate (KPS) exhibited exceptional photoinitiation efficiency for various biomaterials, including silk fibroin, gelatin, poly(ethylene glycol) diacrylate, and carboxymethyl cellulose modified with amino acids. Furthermore, the cytocompatibility of the FMN-/KPS photoinitiator was demonstrated by the survival rates of 3T3-LI fibroblasts encapsulated in it, which exceeded 95 % when compared to a commercial initiator. STATEMENT OF SIGNIFICANCE: By introducing persulfate, the photoinitiation efficiency of flavin mononucleotide was significantly improved. The application scenarios of flavin mononucleotide and persulfate combinations were also greatly extended, including radical photopolymerization, dityrosine, diphenylalanine, and ditryptophan coupling crosslinking. Among them, the coupling crosslinking of amino acids (di-phenylalanine, and di-tryptophan) modified carboxymethyl cellulose, to our knowledge, was first reported. The excellent cytocompatibility of cell encapsulation further proved that the combinations of flavin mononucleotide and persulfate have great potential in tissue engineering.

针对蚕种和蚕茧生产省力化、规模化的发展需求,选育出综合经济性状优良的斑纹限性抗血液型脓病家蚕新品种农科5号.浙江省家蚕新品种实验室鉴定结果显示,农科5号的4龄起蚕虫蛹率与对照(秋丰×白玉)相仿,万蚕产茧量、万蚕茧层量分别比对照提高11.34％、15.12％;洁净94.98分,出丝率比对照高1.17百分点.浙江省农村生产试验结果显示,农科5号的张种产茧量48.2 kg,比对照提高9.54％;健蛹率96.56％,比对照提高2.92百分点.抗血液型脓病检测结果表明农科5号的抗病指标为对照的161倍.新品种于2021年5月通过浙江省主要农作物品种审定委员会审定,适合在浙江全省蚕区春期及条件较好的区域秋期饲养.

Artificial parthenogenetic induction via thermal stimuli in silkworm is an important technique that has been used in sericultural production. However, the molecular mechanism underlying it remains largely unknown. We have created a fully parthenogenetic line (PL) with more than 85% occurrence and 80% hatching rate via hot water treatment and genetic selection, while the parent amphigenetic line (AL) has less than 30% pigmentation rate and less than 1% hatching rate when undergoing the same treatment. Here, isobaric tags for relative and absolute quantitation (iTRAQ)-based analysis were used to investigate the key proteins and pathways associated with silkworm parthenogenesis. We uncovered the unique proteomic features of unfertilized eggs in PL. In total, 274 increased abundance proteins and 211 decreased abundance proteins were identified relative to AL before thermal induction. Function analysis displayed an increased level of translation and metabolism in PL. After thermal induction, 97 increased abundance proteins and 187 decreased abundance proteins were identified. An increase in stress response-related proteins and decrease in energy metabolism suggested that PL has a more effective response to buffer the thermal stress than AL. Cell cycle-related proteins, including histones, and spindle-related proteins were decreased in PL, indicating an important role of this decrease in the process of ameiotic parthenogenesis.

"农科5号"是浙江省农业科学院蚕桑与茶叶研究所利用引进抗血液型脓病种质资源与多元杂交技术育成的一对四元杂交斑纹限性家蚕新品种,其综合经济性状优良,对血液型脓病具强抵抗力.该品种经2017～2018年两年实验室共同鉴定,2019～2020年两年农村生产试验,于2021年通过浙江省家蚕新品种审定.德清县莫干天竺蚕种有限责任公司于2018年春期首次引进新品种"农科5号"开展一代杂交种试繁,之后分别在2019、2020、2021年,连续进行了4年8期一代杂交种繁育,现将繁育情况简单总结如下.

Seminal fluid proteins provide factors necessary for development, storage, and activation of sperm. Altered expression of seminal fluid proteins can lead to defect in male infertility. We investigated the function of seminal fluid protein Sfp62 in the model lepidopteran insect Bombyx mori using CRISPR/Cas9 mediated mutagenesis. The knockout of BmSfp62 gene led to male sterility but has no effect on female fertility. The mutation did not affect growth and development of the silkworm of both sexes. Motility of sperm in male mutants was decreased and the mRNA expression levels of other genes encoding seminal fluid proteins were altered in BmSfp62 mutants compared to the wild-type controls. The male sterility caused by mutation of BmSfp62 was stably inherited. As the proteins encoded by Sfp62 genes are conserved among lepidopteran species, Sfp62 is a potential target for the biological management of lepidopteran pests.

家蚕人工诱导的孤雌生殖可以获得和母本基因型完全一致的全雌后代,在家蚕遗传育种、转基因研究、杂种优势机理和早期胚胎发育研究等方面具有重要价值.本文介绍了家蚕人工诱导孤雌生殖在发生机制研究及实际应用中的主要进展.

针对蚕丝被消费市场对原料茧的巨大需求,利用茧型大、茧层厚的家蚕种质资源,通过杂交育种并结合纯系分离定向选择技术,育成了万蚕产茧层量高、茧丝纤度粗的蚕丝被生产专用家蚕新品种丝棉1号.该品种具有孵化眠起齐一、熟蚕齐涌、茧型大、茧层厚、双宫茧率高的特点,具体表现为万蚕产茧量和万蚕产茧层量分别比对照品种秋丰×白玉提高16.05％和22.75％,茧丝纤度＞3.556 dtex,出丝率高出对照品种0.89百分点,出棉率比对照高3.29百分点,丝棉的压缩率(55.20％)和回复率(93.0％)均达到蚕丝被国家标准中优等品的指标要求.丝棉1号于2020年5月通过浙江省主要农作物品种审定委员会审定,适宜在华东地区环境条件较好的季节饲养.

Phellinus gilvus (Schwein.) Pat, a species of ‘Sanghuang’, has been well-documented for various medicinal uses, but the genome information and active constituents are largely unknown. Here, we sequenced the whole-genome of P. gilvus, identified phenylpropanoids as its key anti-cancer components, and deduced their biosynthesis pathways. A 41.11-Mb genome sequence was assembled and the heatmap created with high-throughput chromosome conformation capture techniques data suggested all bins could be clearly divided into 11 pseudochromosomes. Cellular experiments showed that P. gilvus fruiting body was more effective to inhibit hepatocellular carcinoma cells than mycelia. High resolution electrospray ionization mass spectroscopy (HR-ESI-MS) analysis revealed P. gilvus fruiting body was rich in phenylpropanoids, and several unique phenylpropanoids in Phellinus spp. exhibited potent anti-carcinogenesis activity. Based on genomic, HR-ESI-MS information and differentially expressed genes in transcriptome analysis, we deduced the biosynthesis pathway of four major phenylpropanoids in P. gilvus. Transcriptome analysis revealed the deduced genes expressions were synergistically changed with the production of phenylpropanoids. The optimal candidate genes of phenylpropanoids’ synthesis pathway were screened by molecular docking analysis. Overall, our results provided a high-quality genomic data of P. gilvus and inferred biosynthesis pathways of four phenylpropanoids with potent anti-carcinogenesis activities. These will be a valuable resource for further genetic improvement and effective use of the P. gilvus.

利用家蚕斑纹限性种质资源和杂交育种技术,选育获得优良家蚕新品系并组配杂交组合,育成了综合经济性状优良的斑纹全限性四元杂交多丝量家蚕新品种农科2号.经浙江省家蚕新品种实验室鉴定和农村生产试验表明,该品种孵化、眠起、上蔟齐一,茧型大、产量高,茧丝质性状优.与对照品种菁松×皓月相比,其龄期经过相仿,虫蛹率高出0.43百分点,万蚕产茧量提高3.74％,万蚕产茧层量提高4.49％,洁净94.60分,出丝率高于对照品种.蚕种生产过程中,4龄初期即可通过蚕体斑纹鉴别雌雄,并且其雄蛾可进行多次交配,在大蚕期可适当多养雌蚕而少养雄蚕,有效提高蚕种生产效率与杂交率,降低蚕种生产成本.新品种于2018年4月通过浙江省农作物品种审定委员会审定,适宜在江浙蚕区春季及晚秋季饲养.

Bombyx mandarina is generally thought to be the wild ancestor nearest to the domesticated silkworm, B. mori. Here, we sequenced and assembled a complete mitochondrial genome (mitogenome) of B. mandarina. The mitogenome contains 13 protein-coding genes (PCGs), 22 tRNA genes, 2 rRNA genes, and one A + T-rich region. Phylogenetic analysis confirmed that B. mori is more closely related to the Chinese B. mandarina than the Japanese B. mandarina. The new mitogenome provides useful information to further explore the origin and domestication of this species.

Intensive investigations have been conducted on the effect of sole drought or salinity stress on the growth of plants. However, there is relatively little knowledge on how plants, particularly woody species, respond to a combination of these two stresses although these stresses can simultaneously occur in the field. In this study, mulberry, an economically important resource for traditional medicine, and the sole food of domesticated silkworms was subjected to a combination of salt and drought stress and analyzed by physiological methods and TMT-based proteomics. Stressed mulberry exhibited significant alteration in physiological parameters, including root/shoot ratio, chlorophyll fluorescence, total carbon, and ion reallocation. A total of 577 and 270 differentially expressed proteins (DEPs) were identified from the stressed leaves and roots, respectively. Through KEGG analysis, these DEPs were assigned to multiple pathways, including carbon metabolism, photosynthesis, redox, secondary metabolism, and hormone metabolism. Among these pathways, the sucrose related metabolic pathway was distinctly enriched in both stressed leaves and roots, indicating an important contribution in mulberry under stress condition. The results provide a comprehensive understanding of the adaptive mechanism of mulberry in response to salt and drought stress, which will facilitate further studies on innovations in terms of crop performance.

Male-only rearing has long been desirable in sericulture because males have superior economic characteristics. To this end, a balanced sex-linked lethal (BSL) system has been developed. Here, we report the first complete mitochondrial genome of the BSL silkworm (Bombyx mori). Phylogenetic analysis revealed that the BSL silkworm is more closely related to Japanese B. mori than Chinese B. mori. The new mitochondrial genome provides valuable information to further explore genetic diversity and origin of this species.

Lysine succinylation is a newly identified protein post-translational modification (PTM) of lysine residues. Increasing evidences demonstrate that this modification is prevalent in mitochondria and regulates many vital cellular processes, especially metabolism. Here, we determined the succinylome of the silkworm (Bombyx mori) midgut mitochondria during the larval gluttonous stage (the fifth instar) using succinylated peptides enrichment coupled with nano HPLC/MS/MS. A total of 1884 lysine succinylation sites on 373 mitochondrial proteins were identified. The bioinformatic analysis reveal that succinylated proteins are significantly enriched in central metabolic processes and mitochondrial protein synthesis. Several apoptosis and detoxification related enzymes or proteins are succinylated. The findings suggest the crucial role of lysine succinylation in silkworm midgut metabolism and resistance. Our data provide a rich resource for further analysis of lysine succinylation in silkworm.SIGNIFICANCE:Insect midgut is the vital tissue for nutrient metabolism and also for xenobiotic metabolism. There is a growing body of knowledge on regulation of midgut function at the gene or protein levels in silkworm, however, the regulation at post-translation modification level remains largely unknown. We provide a first global analysis of the mitochondrial lysine succinylome in silkworm midgut. A total of 1884 lysine succinylation sites on 373 mitochondrial proteins were identified. Bioinformatics results suggest an important role of this modification in regulating metabolism and mitochondrial protein synthesis. Our data greatly expand the catalog of lysine succinylation substrates and sites in insects, and represents an important resource for understanding the physiological function of lysine succinylation in insect midgut.