Orange Leafhopper Cicadulina bipunctata Feeding Induces Gall Formation Nitrogen Dependently and Regulates Gibberellin Signaling

Abstract

Orange leafhopper Cicadulina bipunctata feeding induces wallaby ear symptoms, namely growth suppression and gall formation characterized by severe swelling of leaf veins, on various Poaceae, thereby leading to low crop yields. Here, we investigated the development of wallaby ear symptoms on rice seedlings due to C. bipunctata feeding. After confirming that C. bipunctata feeding induces growth suppression and gall formation on rice seedlings, we further demonstrated that gall formation score decreased with decreasing levels of nitrogen in the medium and that C. bipunctata feeding induces the expression levels of nitrogen transporter genes. These gene expression changes may participate in the nutrient accumulation observed in galled tissues and in gall formation. In addition, these expression changes should induce growth promotion but the inhibition of gibberellin signaling by C. bipunctata feeding might be the reason why growth is suppressed. Treatment with plant growth regulators did not affect gall formation, suggesting the existence of a complex gall formation mechanism by C. bipunctata feeding.

Insights of Improved Aroma under Additional Nitrogen Application at Booting Stage in Fragrant Rice

“…Appropriate N applications were applied in many plants for improved cultivation and increased yield and quality, as well as for protecting the soil mineral from depletion. Although it is widely known that N is able to substantially regulate the rice phenological development, productivity and grain quality features of rice [ 15 ], the influence of N on the aroma of fragrant rice has received less attention. Additionally, 2-AP was easily affected by biotic factors such as temperature and light, and appropriate N application was a suitable and feasible strategy to modulate the 2-AP content [ 1 , 4 ].…”