Plant jasmonic acid mediated contrasting effects of two citrus aphid species on Diaphorina citri Kuwayama

Background Herbivores may influence each other directly and through plant mediated inter-specific interactions. The Asian citrus psyllid (Diaphorina citri Kuwayama) and citrus aphids are key pests that can co-exist on citrus, but their plant-mediated interaction between them is unknown. Here we investigated plant-mediated effect of two citrus aphid species, the polyphagous Aphis spiraecola Patch and the oligophagous Aphis (Toxoptera) citricidus (Kirkaldy) on the feeding behavior and reproduction of Diaphorina citri, and explored the underlying mechanisms. Results In comparison with those on aphid free plants, Diaphorina citri had decreased reproduction and reduced phloem feeding on Aphis spiraecola pre-infested plants, while the reproduction and feeding efficiency were increased on Aphis citricidus pre-infested plants. Jasmonic acid (JA) dependent defense was significantly activated by Diaphorina citri feeding on Aphis spiraecola pre-infested plants, but was suppressed by Diaphorina citri feeding on Aphis citricidus pre-infested plants compared with that on aphid free plant. By contrast, only one tested marker gene in salicylic acid (SA) signaling was activated by Diaphorina citri feeding on Aphis spiraecola pre-infested plants. Furthermore, exogenous application of methyl jasmonate, but not SA, conferred resistance against Diaphorina citri in our citrus trials. Conclusion Our results indicate that pre-infestation by two citrus aphid species differentially altered Diaphorina citri induced citrus JA dependent defense, which resulted in different effect on subsequent Diaphorina citri performance. (c) 2022 Society of Chemical Industry.

Automated summary

This study found that the citrus aphid species Aphis spiraecola and Aphis citricidus have different plant-mediated effects on the feeding and reproduction of the Asian citrus psyllid Diaphorina citri, by activating or suppressing citrus JA dependent defense, thus affecting subsequent psyllid performance.