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ARS Home » Southeast Area » Tifton, Georgia » Crop Genetics and Breeding Research » Research » Publications at this Location » Publication #400365
Research Project: Genetic Improvement of Maize and Sorghum for Resistance to Biotic and Abiotic Stresses

Location: Crop Genetics and Breeding Research

Title: Identification of the flavone-inducible counter-defense genes and their cis-elements in Helicoverpa armigera

Author
item DENG, ZHONGYUAN - Zhengzhou University
item ZHANG, YUTING - Zhengzhou University
item FANG, LIYING - Zhengzhou University
item ZHANG, MIN - Zhengzhou University
item WANG, LIXIANG - Zhengzhou University
item Ni, Xinzhi
item LI, XIANCHUN - University Of Arizona

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/12/2023
Publication Date: 5/29/2023
Citation: Deng, Z., Zhang, Y., Fang, L., Zhang, M., Wang, L., Ni, X., Li, X. 2023. Identification of the flavone-inducible counter-defense genes and their cis-elements in Helicoverpa armigera. Toxins. 15:365. https://doi.org/10.3390/toxins15060365.
DOI: https://doi.org/10.3390/toxins15060365

Interpretive Summary: The application of chemical pesticides has caused environmental problems. Thus, it is very important to find eco-friendly biopesticides. Secondary metabolites of plants, such as flavones, are important resources for pest management. Flavones are widely found in plants, and play an important role in plant defense against insect pests. The current study identified the key genes and regulatory element involvement in flavone metabolism in the old-world corn earworm. The up-regulated gene expressions and cis-acting element play an important role in detoxification of flavones in the old-world corn earworm. This study is of great significance for further understanding the relationship between plants and herbivorous insects and revealing the host adaptation mechanism of insects in general.

Technical Abstract: Flavone is an anti-herbivory allelochemical produced by most plants to defend themselves against insect feeding. Upon exposure to flavone, some insect pests can upregulate a variety of co-regulated counter-defense genes to detoxify it. Yet, the nature of the flavone-inducible genes and their linked cis-regulatory elements remain unknown. The current study utilized Helicoverpa armigera as a model to address this issue. Transcriptomic analysis showed that administration of 0.1% flavone to the newly-molted 6th instar larvae caused up- and down- regulation of 38 and 10 genes, respectively, in the midgut. These differentially expressed genes (DEGs) mainly concentrated in the retinol and allelochemical metabolisms, or the cytochrome P450 pathway. In addition, we further studied the promoters of 24 up-regulated genes, predicted two motifs through Multiple Expectation Maximizations for Motif Elicitation (MEME), and predicted known elements related to toxin metabolism such as cis-acting element (ARE). Finally, the function of the element was verified in the promoter of up-regulated gene CCE001j, and the results showed that the two motifs were not induced by flavones. The ARE1 element plays a decisive role as the promoter in responding to flavones. In this study, up-regulated expression of cytochrome P450 and carboxylesterase genes may enhance the detoxification of flavones in H. armigera, and ARE1 element plays an important role in cis-transcriptional regulation of CCE001j. This study is of great significance for further understanding the relationship between plants and herbivorous insects and revealing the host adaptation mechanism of insects.