Maize bushy stunt phytoplasma changes the emission of maize volatiles and the chemotaxis of non-infected Dalbulus maidis (Hemiptera: Cicadellidae)

Abstract

The corn leafhopper, Dalbulus maidis, transmits phytopathogens that cause significant economic losses in Zea mays. The maize bushy stunt phytoplasma (MBSP) indirectly affects insect vectors behavior through morphological and physiological changes in host plants. This study evaluated the effect of MBSP-infected and sham-infected maize plants on the host selection of D. maidis. Dual-choice tests were performed with non-infected D. maidis females using a Y-tube olfactometer. Volatile organic compounds (VOCs) from MBSP-infected and sham-infected genotypes were collected and characterized. Our results showed that MBSP infection altered the VOC profiles of both maize genotypes. In the P4285VYHR hybrid maize, MBSP infection induced the release of six new compounds and increased the levels of nine others. Non-infected D. maidis discriminated between MBSP-infected and sham-infected P4285VYHR plants, showing a preference for VOCs emitted by infected plants. In contrast, MBSP infection in the SCS156 Colorado genotype led to the emission of three new compounds and increased the release of two others. For this genotype, non-infected females preferred the odors of sham-infected plants over clean air. Our findings show that non-infected D. maidis recognizes maize VOCs and selectively responds to MBSP-infected plants, particularly in a hybrid genotype.