Mulberry leaf is an excellent protein resource that can be used as feed additive for livestock and poultry. Nevertheless, the use of mulberry leaves in animal diets is limited by its protease inhibitors, tannic acid and other anti-nutritional factors. This study systematically analyzed the type and activity of serine protease inhibitors (SPIs) from the leaves of 34 mulberry varieties, aiming to reveal the physicochemical properties and inactivation mechanism of SPIs. The types and activities of trypsin inhibitors (TIs) and chymotrypsin inhibitors (CIs) exhibited polymorphisms among different mulberry varieties. The highest number of types of inhibitors was detected in Jinshi, with six TIs (TI-1~TI-6) and six CIs (CI-1~CI-6). TIs and CIs exhibited strong thermal and acid–base stability. High-temperature and high-pressure treatment could reduce the activities of TIs and CIs to a certain extent. β-mercaptoethanol treatment could completely abolish TIs and CIs, suggesting that the disulfide bridges were critical for their inhibitory activities. The Maillard reaction could effectively eliminate the inhibitory activities of TI-1~TI-4 and CI-1~CI-4. This study reveals the physicochemical properties and inactivation mechanisms of the anti-nutritional SPIs from mulberry leaves, which is helpful to exploit mulberry-leaf food with low-activity SPIs, promote the development and utilization of mulberry-leaf resources in animal feed and provide reference for mulberry breeding with different functions.

The Deltocephalinae (Cicadellidae), the largest globally distributed leafhopper subfamily, comprises predominantly pestiferous taxa, though its tribal classification remains unresolved. Insect mitochondrial genomes (mitogenomes) exhibit conserved composition and moderate evolutionary rates, making them robust markers for phylogenetic reconstruction. Here, we sequenced the mitogenome of Hishimonus sellatus Uhler, a key pest, and performed comparative and phylogenetic analyses of 47 Deltocephalinae species. The complete mitogenome of H. sellatus spanned 14,690 bp and comprised 37 genes, including 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, and 22 transfer RNA genes (tRNAs). Its gene order was identical to that of ancestral arthropods, and the genes were tightly arranged, with 11 gene overlaps totaling 38 bp. All the PCGs used standard ATN as the start codon, except nad5, which used UUG. 11 PCGs used TAN as the termination codons, but nad4 and nad5 used T. The A + T content of the PCGs was 73.12%, and the most frequently used codons were composed of A and U nucleotides. In addition, each PCG from the N-strand showed a positive GC-skew and a strong negative AT-skew, whereas each PCG from the J-strand displayed a negative GC-skew and a slight AT-skew. The secondary structure of each tRNA was the canonical cloverleaf, except for trnS1(UCU), which lacked the dihydrouridine arm. In total, 46 wobble or mismatched base pairs were detected in 19 tRNA genes. The control region was 253 bp, the shortest among the Deltocephalinae species. The phylogenetic analysis showed that H. sellatus was grouped within the branch of the tribe Opsiini, and the monophyletic clades of the tribes Penthimiini, Selenocephalini, Drabescini, Chiasmini, Paralimnini and Deltocephalini were well resolved and supported. This study identified the currently shortest mitogenome and control region sequences ever reported in Deltocephalinae species, measuring 14,690 bp and 253 bp, respectively. The phylogenetic analyses among Deltocephalinae species well supported that Hishimonus belongs to the tribe Opsiini and the monophyletic groups of tribes Penthimiini, Selenocephalini, Drabescini, Chiasmini, Paralimnini and Deltocephalini, providing valuable insights into their classification and evolutionary status. The online version contains supplementary material available at 10.1186/s12864-026-12620-2.

Phytoplasmas are phloem-limited plant pathogens that cause substantial economic losses in global agriculture. Complete genome sequences are essential for c