Abstract: The impacts of T-DNA intergenic insertion on rice agronomic characters, feeding preference and population abundance of sucking insect pests on T-DNA inserted rice mutants were evaluated for unintended effects resulted from transgenic manipulation or gene insertion. The results indicated that the expression of the OPR (12-oxophytodienoate reductase) gene near the insertion site was not affected in all the four mutant lines ZD1640-3, ZD1640-19, ZD1640-23 and ZD1640-24. Major agronomic characters were not significantly different from those of the non-transgenic parent control except for a decrement in plant height, grain number per spike or seed setting rate in several lines. The average population densities of Nilaparvata lugens, Sogatella furcifera and Nephotettix bipunctatus on mutant lines showed no significant difference with those on patent control Zhonghua 11, except that on the mutant line ZD1640-24, average population density of planthoppers was significantly reduced. However, population dynamics of each sucking pests showed no significant difference on mutant lines with those on non-transgenic parent control on most sampling days. In addition, no significant differences in the resistance to N. lugens and feeding preference of N. lugens were found between the mutant line ZD1640-24 and its parent control either. Our results indicate that the variation between mutant lines and non-transgenic parent was more result from the individual variation than from T-DNA insertion.

Key words: rice, T-DNA insertion, sucking-mouthpart insect pests, feeding preference, population density, unintended effects