Chitin deacetylases(CDAs,including CDAI and CDA2)are considered key enzymes for body cuticle formation and tracheal morphogenesis in various insect species.However,their functions in the formation of the cuticular int...Chitin deacetylases(CDAs,including CDAI and CDA2)are considered key enzymes for body cuticle formation and tracheal morphogenesis in various insect species.However,their functions in the formation of the cuticular intima of the foregut and hindgut are unclear.Here,we investigated the roles of their respective genes LmCDAI and Lm-CD42 in this process,in the hemimetabolous insect Locusta migratoria.Transcripts of LmCDAI and LmCDA2 were highly expressed both before and after molting in the foregut.In the hindgut,their expression was high only before molting.In both the foregut and hindgut,LmCDA1 protein was localized in the basal half of the chitin matrix(procuti-cle),whereas LmCDA2 was detected in the upper half of the procuticle.K nockdown of LmCDAI by RNA interference(RNAi)in 5th-instar nymphs caused no visible defcts of the hindgut cuticle.By contrast,the chitinous lamellae of the cuticular intima in the foregut of knockdown animals were less compact than in control animals.RNAi against LmCDA2 led to thickening of both the foregut and hindgut cuticles,with a greater number of thinner laminae than in the respective control cuticles.Taken together,our results show that LmCDAI and LmCDA2 have distinct,but overlapping,functions in chitin organization in the foregut cuticle.However,in the hindgut,this process seems independent of LmCDA1 activity but requires LmCDA2 function.Thus,the CDAs reflect tissue-specific differences in cuticular organization and function,which need further detailed molecular and histological analyses for full comprehension.展开更多
The foregut,located at the front of the digestive tract,serves a vital role in in-sects by storing and grinding food into small particles.The innermost layer of the foregut known as the chitinous intima,comes into dir...The foregut,located at the front of the digestive tract,serves a vital role in in-sects by storing and grinding food into small particles.The innermost layer of the foregut known as the chitinous intima,comes into direct contact with the food and acts as a protec-tive barrier against abrasive particles.Knickkopf(Knk)is required for chitin organization in the chitinous exoskeleton,tracheae and wings.Despite its significance,lttle is known about the biological function of Knk in the foregut.In this study,we found that LmKnk was stably expressed in the foregut,and highly expressed before molting in Locusta migrato-ria.To ascertain the biological function of LmKnk in the foregut,we synthesized specific double-stranded LmKnk(dsLmKnk)and injected it into locusts.Our findings showed a significant decrease in the foregut size,along with reduced food intake and accumulation of residues in the foregut after dsLmKnk injection.Morphological observations revealed that newly formed intima became thinner and lacked chitin lamella.Furthermore,fluores-cence immunohistochemistry revealed that LmKnk was located in the apical region of new intima and epithelial cells.Taken together,this study provides insights into the biological function of LmKnk in the foregut,and identifies the potential target gene for exploring biological pest management strategies.展开更多
基金the National Natural Science Foundation of China(Grant No.31672364,31761133021,32072419,31701794,31801749)the Pro-gram for Top Young Academic Leaders of Higher Learn-ing Institutions of Shanxi(TYAL)2017+1 种基金Scientific and Technological Innovation Programs of Higher Edu-cation Institutions in Shanxi(2017104)BM's contribu-tion was supported by the German Research Foundation(DFG grant MO1714/10-1).
文摘Chitin deacetylases(CDAs,including CDAI and CDA2)are considered key enzymes for body cuticle formation and tracheal morphogenesis in various insect species.However,their functions in the formation of the cuticular intima of the foregut and hindgut are unclear.Here,we investigated the roles of their respective genes LmCDAI and Lm-CD42 in this process,in the hemimetabolous insect Locusta migratoria.Transcripts of LmCDAI and LmCDA2 were highly expressed both before and after molting in the foregut.In the hindgut,their expression was high only before molting.In both the foregut and hindgut,LmCDA1 protein was localized in the basal half of the chitin matrix(procuti-cle),whereas LmCDA2 was detected in the upper half of the procuticle.K nockdown of LmCDAI by RNA interference(RNAi)in 5th-instar nymphs caused no visible defcts of the hindgut cuticle.By contrast,the chitinous lamellae of the cuticular intima in the foregut of knockdown animals were less compact than in control animals.RNAi against LmCDA2 led to thickening of both the foregut and hindgut cuticles,with a greater number of thinner laminae than in the respective control cuticles.Taken together,our results show that LmCDAI and LmCDA2 have distinct,but overlapping,functions in chitin organization in the foregut cuticle.However,in the hindgut,this process seems independent of LmCDA1 activity but requires LmCDA2 function.Thus,the CDAs reflect tissue-specific differences in cuticular organization and function,which need further detailed molecular and histological analyses for full comprehension.
基金This work was supported by the National Natural Science Foundation of China(31801749)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province(2019L0796)the Department of Science and Technology in Guangdong Province(2019B090905003).
文摘The foregut,located at the front of the digestive tract,serves a vital role in in-sects by storing and grinding food into small particles.The innermost layer of the foregut known as the chitinous intima,comes into direct contact with the food and acts as a protec-tive barrier against abrasive particles.Knickkopf(Knk)is required for chitin organization in the chitinous exoskeleton,tracheae and wings.Despite its significance,lttle is known about the biological function of Knk in the foregut.In this study,we found that LmKnk was stably expressed in the foregut,and highly expressed before molting in Locusta migrato-ria.To ascertain the biological function of LmKnk in the foregut,we synthesized specific double-stranded LmKnk(dsLmKnk)and injected it into locusts.Our findings showed a significant decrease in the foregut size,along with reduced food intake and accumulation of residues in the foregut after dsLmKnk injection.Morphological observations revealed that newly formed intima became thinner and lacked chitin lamella.Furthermore,fluores-cence immunohistochemistry revealed that LmKnk was located in the apical region of new intima and epithelial cells.Taken together,this study provides insights into the biological function of LmKnk in the foregut,and identifies the potential target gene for exploring biological pest management strategies.
