TY - JOUR
T1 - Expressional divergence of insect GOX genes
T2 - From specialist to generalist glucose oxidase
AU - Yang, Lihong
AU - Wang, Xiongya
AU - Bai, Sufen
AU - Li, Xin
AU - Gu, Shaohua
AU - Wang, Chen Zhu
AU - Li, Xianchun
N1 - Funding Information: This work was supported by USDA National Institute of Food and Agriculture (hatch grant ARZT-1360890-H31-164 and multi state grant ARZT-1370400-R31-168), the National Natural Science Foundation of China (grant 31171874 and 31321004) and State Key Laboratory for Biology and of Plant Diseases and Insects (grants SKLOF201402 and SKLOF201504). Publisher Copyright: © 2017 Elsevier Ltd
PY - 2017/7/1
Y1 - 2017/7/1
N2 - Insect herbivores often secrete glucose oxidase (GOX) onto plants to counteract plant defenses and potential pathogens. Whether generalist herbivores always have significantly higher GOX activities than their specialist counterparts at any comparable stage or conditions and how this is realized remain unknown. To address these two general questions, we subjected larvae of a pair of sister species differed mainly in host range, the generalist Helicoverpa armigera and its specialist counterpart Helicoverpa assulta, to the same sets of stage, protein to digestible carbohydrate (P:C) ratio, allelochemical or host plant treatments for simultaneous analyses of GOX transcripts and activities in their labial glands. GOX activity and transcripts are upregulated concurrently with food ingestion and body growth, downregulated with stopping ingestion and wandering for pupation in both species. The three tested host plants upregulated GOX transcripts, and to a lesser extent, GOX activity in both species. There were significant differences in both GOX transcripts and activity elicited by allelochemicals, but only in GOX transcripts by P:C ratios in both species. GOX activities were higher in H. armigera than H. assulta in all the comparable treatments, but GOX transcripts were significantly higher either in generalists or in specialists, depending on the developmental stages, host plants, P:C ratio and allelochemicals they encounter. These data indicate that the greater GOX activity in generalist herbivores is not achieved by greater transcription rate, but by greater transcript stability, greater translation rate, better enzyme stability and/or their combination.
AB - Insect herbivores often secrete glucose oxidase (GOX) onto plants to counteract plant defenses and potential pathogens. Whether generalist herbivores always have significantly higher GOX activities than their specialist counterparts at any comparable stage or conditions and how this is realized remain unknown. To address these two general questions, we subjected larvae of a pair of sister species differed mainly in host range, the generalist Helicoverpa armigera and its specialist counterpart Helicoverpa assulta, to the same sets of stage, protein to digestible carbohydrate (P:C) ratio, allelochemical or host plant treatments for simultaneous analyses of GOX transcripts and activities in their labial glands. GOX activity and transcripts are upregulated concurrently with food ingestion and body growth, downregulated with stopping ingestion and wandering for pupation in both species. The three tested host plants upregulated GOX transcripts, and to a lesser extent, GOX activity in both species. There were significant differences in both GOX transcripts and activity elicited by allelochemicals, but only in GOX transcripts by P:C ratios in both species. GOX activities were higher in H. armigera than H. assulta in all the comparable treatments, but GOX transcripts were significantly higher either in generalists or in specialists, depending on the developmental stages, host plants, P:C ratio and allelochemicals they encounter. These data indicate that the greater GOX activity in generalist herbivores is not achieved by greater transcription rate, but by greater transcript stability, greater translation rate, better enzyme stability and/or their combination.
KW - Allelochemicals
KW - GOX expression
KW - Helicoverpa spp
KW - Host plant range
KW - P:C ratio
KW - Post-transcriptional regulation
KW - RNA stability
KW - Translation
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U2 - 10.1016/j.jinsphys.2017.05.003
DO - 10.1016/j.jinsphys.2017.05.003
M3 - Article
C2 - 28512014
SN - 0022-1910
VL - 100
SP - 21
EP - 27
JO - Journal of insect physiology
JF - Journal of insect physiology
ER -