Potassium application for increased jasmonic acid content and defense enzyme activities of wheat leaves infested by aphids

Wheat is the second most planted crop in the world and plays an important role in China and the world's food security. Aphids are a serious insect pest group for the worldwide wheat growing area and pose a critical threat to wheat yield. It is known that in modem agriculture crop yield largely depends upon fertilizer input, whereas the occurrence of insect herbivores is closely related to the nutrient status in the plant tissues supplied by soil fertility. The prevailing view is that a high potassium level in plant tissues supplied by the soil decreases the occurrence of many pests. In this paper, the effects of potassium supply on signal molecular contents and defense enzymes activities of wheat leaves infested by aphids (Sitobion avenae) were investigated. Solution culture was used in the experiment and two potassium (K) levels were applied, 2 mmol/L and 0.005 mmol/L KCl, respectively. Our results showed that K-deficient wheat susceptibility to aphids might be due to K-deficient wheat could not initiate the signaling transduction effectively or activate the defense system alter aphid infestation.