Abstract
Tetraneura nigriabdominalis is distributed in Japan and known as an insect pest against the Gramineous crops such as the upland rice plant, wheat, and barley. The female nymphs hatching from eggs in the spring on the primary hosts, Ulmus tree, produce galls on the leaf. After development of winged aphids in a gall, the winged aphids are dispersing in the field and infest the root of the Gramineous plant. Here, we investigated a gall formation by aphids on leaves of Ulmus parvifolia and change of metabolites in gall. Ionic chemicals contained in galls and uninfected leaves were extracted with MeOH and extracts were analyzed by the CE-TOF (Agilent G3250AA LC/MSD TOF system). Separations were carried out using a fused silica capillary (50um i.d.×100cm) filled with 1M formic acid for cation analyses or with 20mM ammonium formate for anion analyses as the electrolyte. The concentrations of amino acids in galls were increased than those in intact leaves, and among them the concentration of Asn in galls was 15 times higher than that in intact leaves. The time course experiments revealed that the concentration of Asn in galls was increased with gall development and it was decreased after dispersing of winged aphids. On the other hand the concentration in intact leaves was decreased during leaf development. These results suggest that the nutrition conditions of plant for aphids have been improved by gall formation.
