Identification and Characterization of <i>Hibiscus mutabilis</i> Varieties Resistant to <i>Bemisia tabaci</i> and Their Resistance Mechanisms.

Abstract

<i>Hibiscus mutabilis</i>, the city flower of Chengdu, is culturally significant and has nutritional and medicinal benefits. However, frequent infestations of <i>Bemisia tabaci</i> have caused economic losses. This study aimed to identify insect-resistant <i>H. mutabilis</i> 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 <i>B. tabaci</i> 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 <i>B. tabaci</i> 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 <i>H. mutabilis</i> varieties and developing eco-friendly strategies against <i>B. tabaci</i> infestations.