Identification and Characterization of Hibiscus mutabilis Varieties Resistant to Bemisia tabaci and Their Resistance Mechanisms

TL;DR

This study identifies Hibiscus mutabilis varieties resistant to whiteflies and explores their chemical defense mechanisms.

Contribution

The study identifies specific Hibiscus varieties and their resistance-linked metabolites, offering a strategy for breeding pest-resistant plants.

Findings

Jinqiusong and Bairihuacai Hibiscus varieties show strong resistance to Bemisia tabaci.

Fifteen key metabolites and the phenylpropanoid pathway are linked to resistance.

Volatile compounds like 2-ethylhexanol repel whiteflies.

Abstract

This study investigated the resistance of Hibiscus mutabilis varieties to the whitefly Bemisia tabaci. It identified the highly resistant variety Jinqiusong (JQS) and moderately resistant Bairihuacai (BRHC), which showed significantly lower B. tabaci populations than the susceptible variety Chongbanbai (CBB). Metabolomic analysis revealed that fifteen key metabolites are linked to resistance, with the phenylpropanoid biosynthesis pathway being critical in defense. Additionally, volatile compounds emitted by the resistant varieties deterred the pest’s behavior. The findings offer a theoretical basis for breeding insect-resistant H. mutabilis varieties, providing a sustainable strategy for managing B. tabaci infestations.

Hibiscus mutabilis, the city flower of Chengdu, is culturally significant and has nutritional and medicinal benefits. However, frequent infestations of Bemisia tabaci have caused economic losses. This study aimed to identify insect-resistant H. mutabilis varieties. Over two years, varieties like Jinqiusong, Zuiyun, and Zuifurong showed moderate to high resistance based on reproductive indices. Assessments of antixenosis and developmental impacts revealed that adult B. tabaci exhibited low selectivity toward these resistant varieties, indicating a strong repellent effect. Gas chromatography-mass spectrometry analysis identified volatile organic compounds, such as alcohols, alkanes, and terpenes. Notably, 2-ethylhexanol and 6-methylheptanol exhibited repellent properties. Using nontargeted metabolomics, this study compared the metabolite profiles of the insect-resistant variety Jinqiusong (JQS), moderately resistant Bairihuacai (BRHC), and highly susceptible Chongbanbai (CBB) post B. tabaci infestation. Fifteen key metabolites were linked to resistance, emphasizing the phenylpropanoid biosynthesis pathway as crucial in defense. These findings offer a theoretical foundation for breeding insect-resistant H. mutabilis varieties and developing eco-friendly strategies against B. tabaci infestations.

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