Metabolites with benzene ring from sugarcane leaf play important role in plant-Spodoptera frugiperdainteraction

Abstract

AbstractSecondary metabolism plays important role in plant growth and development, however, the relationship between secondary metabolism and adaptive plant-insect communication is largely unknown. The present study used sugarcane line highly susceptible toSpodoptera frugiperdaand sister line with medium resistance to analyze the role of plant non-volatile organic compounds (NOCs) and volatile organic compounds (VOCs) in sugarcane-S. frugiperdainteraction. A total of 46 plant NOCs and 15 plant VOCs significantly different between resistant and susceptible lines and were continuously up-regulated and down-regulated at different time points before/afterS.frugiperdatreatment were screened. Phenolic acids containing benzene ring accounted for the largest proportion of differential NOCs. Levels of 66.7% of these phenolic acids were higher in susceptible line. Feeding supplemented with NOCs showed that phenoxyacetic acid (phenolic acid) and 4-methoxybenzaldehyde (aromatic phenolic acid) both increased the male-to-female ratio ofS. frugiperda. Aromatics containing benzene ring, accounted for the largest of differential VOCs in susceptible line. Two aromatics,p-cymene and benzene and 1-ethenyl-4-methoxy-, with higher level in susceptible line, were attractive toS. frugiperda. Terpenoids, aldehyde, and esters accounted for most of higher-in-resistant VOCs, with most tested to be repellent toS. frugiperda. Furthermore, transcriptome analysis ofS. frugiperdafeeding on susceptible and resistant lines combined with feeding assays revealed that tryptophan, as a precursor of aromatic compounds that also contains benzene ring, could promote the growth and development ofS. frugiperdain nutritional deficiency condition. These findings together suggested that benzene-ring containing compounds play a critical role in plant-Spodoptera frugiperdainteraction.