Ca 2+ signal contributing to jasmonic acid‐induced direct and indirect defense against the whitefly Bemisia tabaci in tomato plants

The phytophagous whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) causes serious crop yield losses around the world especially by vectoring viruses. Exogenous jasmonic acid (JA) induces direct plant resistance to B. tabaci , but the underlying mechanism of JA‐induced exogenous defenses is not well understood. Here, we demonstrate that exogenous JA not only increases the cytosolic Ca 2+ concentration ([Ca 2+ ] cyt ) in tomato mesophyll cells but also induces the expression of Ca 2+ ‐sensor genes and plant defense genes. Pre‐treatment with Ca 2+ inhibitor (ruthenium red) significantly repressed the elevation of [Ca 2+ ] cyt , expression of JA‐induced genes, and emission of plant volatiles induced by JA, thus reducing the JA‐induced direct (feeding choice and fitness of B. tabaci ) and indirect [olfactory choice and parasitism by the parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae)] plant resistance to B. tabaci . These results indicate that the Ca 2+ signal induced by JA mediates and directs the plants defenses against whitefly. Present results will not only give us a better understanding of how exogenous JA influences the crop community, but also deliver some clues for the potential application of exogenous JA, as a plant elicitor, in whitefly management.