Electron Beam-Induced Sterility and Inhibition of Ovarian Development in the Sakhalin Pine Longicorn, Monochamus saltuarius (Coleoptera: Cerambycidae).

The Sakhalin pine longicorn, Monochamus saltuarius (Gebler; Coleoptera: Cerambycidae), is an insect vector of the pine wilt nematode (PWN), Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle, and is widely distributed in central Korea. M. saltuarius is a forest pest that seriously damages Pinus densiflora (Siebold et Zucc, Pinales: Pinaceae) and Pinus koraiensis (Siebold & Zucc, Pinales: Pinaceae) forests. We examined the effect of electron beam irradiation on the mating, DNA damage and ovarian development of M. saltuarius adults and sought to identify the optimal dose for sterilizing insects. When the adults were irradiated with electron beams, both females and males were completely sterile at 200 Gy. In a reciprocal crossing experiment between unirradiated and irradiated adults, the reproductive ability of wild adults was recovered by crossing with wild adults even after crossing previously with sterile adults. When a pair of unirradiated adults (♀- × â™‚-) and 10 or 20 irradiated adults (♀+ or ♂+) were kept together, the control effect was as high as 80~90%. After electron beam irradiation at 200 Gy, the DNA of M. saltuarius adults was damaged, the ovarian development of female adults was inhibited, and the level of vitellogenin was significantly decreased compared with that in unirradiated female adults. These results suggest that pine wilt disease can be effectively controlled if a large number of sterilized M. saltuarius male adults are released into the field.

An overexpression of chalcone reductase of Pueraria montana var. lobata alters biosynthesis of anthocyanin and 5'-deoxyflavonoids in transgenic tobacco.

We isolated the chalcone reductase (pl-chr) gene of Pueraria montana var. lobata by using a PCR strategy from cDNA pools of storage roots. A high level of expression of RNA was found in both stems and roots. The genomic Southern blot result suggests that pl-chr exists as a member of a small gene family. By introducing a pl-chr gene under the control of the 35S CaMV promoter into the pink-flowering Xanthi line of Nicotiana tabacum, the flower color was changed from pink to white-to-pink. The contents of anthocyanin in the flowers of the transgenic lines were dramatically decreased by 40%, but the total UV absorption compounds remained unchanged. The production of liquiritigenin in pl-chr overexpressed transgenic tobacco lines was confirmed by HPLC and MS analysis. The introduction of pl-chr gene provides a method to redirect the flavonoid pathway into 5'-deoxyflavonoid production in non-legume crops, in order to manipulate the phenylpropanoid pathway for isoflavonoid production.