Efficient Production of 14-Membered Macrolides by the Endophytic Fungus Colletotrichum gloeosporioides GLL-7 and Their Insecticidal Activity against Diaphorina citri.
TL;DR
Bioactivity-guided fractionation of the fungus Colletotrichum gloeosporioides GLL-7 yielded two macrolides: Sch725674 and Gliomasolide H (GLH), a novel macrolide that possibly targets phospholipid metabolism, disrupting lipid homeostasis and wax formation and is a promising lead compound for controlling D. citri, and C. citri vectors Huanglongbing.
Abstract
The citrus psyllid (Diaphorina citri) vectors Huanglongbing. Overuse of insecticides causes resistance and pollution, necessitating safer alternatives. Bioactivity-guided fractionation of the fungus Colletotrichum gloeosporioides GLL-7 yielded two macrolides: Sch725674 and Gliomasolide H (GLH). Sch725674, a major metabolite produced at 0.035 g per gram of culture medium, is easily obtained via methanol trituration. GLH is a novel macrolide; its structure was elucidated by spectroscopy and confirmed by chemical synthesis. GLH exhibited contact toxicity (24 h LC50 = 0.129 mg/mL) against D. citri; it damaged wax layer, decreased hydrophobicity, lowered nymph emergence rates, and shortened adult body length. Metabolomics, qRT-PCR, and molecular modeling analyses indicated that GLH possibly targets phospholipid metabolism, disrupting lipid homeostasis and wax formation. In addition, GLH exhibited low toxicity to various nontarget organisms. Thus, GLH is a promising lead compound for controlling D. citri, and C. gloeosporioides GLL-7 is a valuable bioresource for producing unusual macrolides.