| Orius strigicollis is a natural enemy insect,mainly distributed in southern cotton fields,preying on pests such as aphids and thrips,and has broad prospects in biological control of agricultural pests,but because its large-scale feeding system is not perfect,it has not been fully applied.In the process of exploring its large-scale feeding system,the research and development of feed is a top priority.Previous laboratory studies have found that during indoor rearing,O.strigicollis that only eat food from animal-based feed have better growth,development and reproduction than O.strigicollis that only eat food from plant-based feed.Exploring the mechanism of different nutrient sources to promote development and reproduction can help to explore the core ingredients needed to improve artificial feed.Therefore,in this study,i TRAQ technology was used to determine the protein group of O.strigicollis feeding on animal-based feed and plant-based feed,and the differentially expressed protein was obtained,and then combined with the differential transcriptome data of different nutrient sources existing in the research group,the digestion genes that may be related to the O.strigicollis response to different food sources were screened,and the biological effect of the target gene on O.strigicollis after silencing was verified by RNAi technology.The differences in the types and activity of insect digestive enzymes are directly related to the nutrients ingested,and the artificial feed formula is improved based on the clues provided by the above study on the feed improvement of the O.strigicollis,the specific results are as follows:1.Using i TRAQ technology to measure the proteome of the O.strigicollis feeding on animal-based feed and plant-based feed,a total of 4586 proteins and 28320 unique peptides were identified.Taking the plant-based feed group as the control,911 differentially expressed proteins were obtained,including 414 up-regulated proteins and 497 down-regulated proteins.Compared with the differentially expressed genes identified in the laboratory,65 genes with the same expression trend were obtained.Combined with functional annotation and expression difference levels,4digestion-related genes were screened out for follow-up research,namely: Cathepsin D-like(Ctsd),Cathepsin L(Ctsl),alpha-N-acetylgalactosaminidase(Naga),Lipase(Lps).2.Using RNAi technology to verify the biological impact of the four genes on the O.strigicollis.After silencing the Ctsd gene,the developmental duration of the5 th instar nymph of the O.strigicollis was significantly prolonged,the eclosion rate and adult acquisition rate were significantly decreased,and the sex ratio in the animal-based feed group was significant,the number of eggs laid in the plant-based feed group decreased significantly.After silencing the Ctsl gene,the body length of the 4th and 5th instar nymphs and adults of the O.strigicollis decreased significantly,and the body weight of the 4th and 5th instar animal-based feed group and the adult plant-based feed group decreased significantly,the developmental duration and total developmental duration of instar nymphs were significantly prolonged,the adult acquisition rate was significantly decreased,the sex ratio was significantly increased,and the egg production was significantly decreased.After silencing the Naga gene,the body length of the 4th and 5th instar nymphs and adults of the O.strigicollis was significantly,the body weight of the 4th and 5th instar animal-based feed group and adult plant-based feed group decreased significantly,the developmental duration and total developmental duration of the 5th instar nymph in the animal-based feed group decreased significantly,the eclosion rate increased significantly,and the ratio of male to female and the amount of eggs laid significantly decreased.After silencing the Lps gene,the body length of the 4th instar nymph and the plant-based feed group of the O.strigicollis decreased significantly,and the body weight of the 4th and 5th instar nymphs and adults also decreased significantly,and adult development duration were significantly prolonged,and the eclosion rate,adult acquisition rate and egg production were all significantly reduced.The above results indicated that the four digestive genes: Ctsd gene,Ctsl gene,Naga gene and Lps gene,were all involved in the development and reproduction of the O.strigicollis.3.In the above research process,it was found that silencing both Ctsl and Lps genes can significantly affect the growth and development of O.strigicollis,and combined with the function and time expression of genes,we speculate that the intake and utilization of fat in O.strigicollis may affect its development and reproduction,and take this as a clue to add octacosanol on the basis of the original artificial feed to obtain a new feed formula.After feeding the O.strigicollis with the new feed,the results showed that: the 3rd instar nymph development period(3.05 ± 0.12 d),the 5th instar nymph development period(5.68 ± 0.17 d)and the total nymph development period(19.47 ± 0.28 d)were significantly shorter than the original plant-based feed(3.53 ± 0.12 d,6.33 ± 0.10 d,21.18 ± 0.24 d).The survival rate of 3rd instar nymphs(85.00 ± 2.69%)and 5th instar nymphs(93.00 ± 2.13%)were significantly improved compared with the original plant-based feed(76.00 ± 2.67%,85.00 ± 2.24%).The adult acquisition rate(58.00 ± 2.91%)was also significantly higher than that of the original plant-based feed(50.00 ± 2.11%).The egg production of a single female(34.30 ± 0.73 grains)increased significantly compared with the original plant-based feed(15.80 ± 0.65 grains).The above results show that the new feed can better promote the growth,development and reproduction of O.strigicollis.In summary,compared with eating plant-based feed,O.strigicollis that feed on animal-based feed have better growth and development,and eating different food sources can affect the expression of Ctsl gene and Lps gene,and then affect the absorption and utilization of fat.Based on this clue,we optimized the original plant-based feed by adding octacosanol to promote the growth and development of O.strigicollis,this provides an important basis for improving artificial feed and increasing the scale of breeding techniques for O.strigicollis. |
PDF Full Text Request