Plant defense responses induced by Bemisia tabaci Middle East—Asia Minor 1 salivary components

The in vivo effects of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Middle East—Asia Minor 1 (MEAM1) saliva on the induced defense of tomato plants were examined. After infiltration of MEAM1 saliva into tomato leaves, qPCR analysis indicated strong local induction of salicylic acid (SA)‐responsive genes — salicylic acid induction deficient 2 (SID2) and β‐1,3‐glucanase (BGL2)— whereas pathogenesis‐related protein‐1 (PR1) showed strong induction both locally and systemically. The jasmonic acid (JA)‐responsive genes — omega‐3 fatty acid desaturase 3 (FAD3), lipoxygenase (LOX), and proteinase inhibitor II (PI‐II) — indicated moderate induction both locally and systemically. The activities of peroxidases and catalase were also induced both locally and systemically, whereas polyphenol oxidase and lipoxygenase were either transiently induced or unchanged. When either MEAM1 or AsiaII_3 whitefly adults were given access to leaves 2 h after saliva infiltration, the number of F1 progeny on the leaves on which the infiltration took place was significantly reduced for both. In contrast, when either MEAM1 or AsiaII_3 adults were given access to leaves 1 day after infiltration, the number of AsiaII_3 progeny was significantly reduced, whereas the number of MEAM1 progeny remained the same as the control. After 2 days, there was no significant difference for the infiltrated leaves for either species. In contrast, 2 h, 1 day, and 2 days after saliva infiltration, the number of F1 MEAM1 progeny on leaves where infiltration did not take place was the same as the controls, whereas the number of AsiaII_3 progeny was significantly reduced. Furthermore, the percentage of MEAM1 adults on leaves with high PR1 and BGL2 RNAs was significantly higher than the percentage of AsiaII_3 adults. Altogether, infiltration of MEAM1 saliva caused intense local defense, as well as moderate, but more persistent systemic defense. Both the SA and JA signaling pathways were regulated by MEAM1 salivary components, and were associated with asymmetric plant defense that favored MEAM1 over AsiaII_3.