Zinc Stress Alters Sugar Content in Rice Plants and the Reproduction and Trehalose Metabolism in Nilaparvata lugens

Excessive zinc (Zn) is toxic to plants, but the effect of zinc-stressed plants on herbivorous insects is still unclear. Hence, we assessed the effect of zinc-stressed rice plants on its feeding pest, Nilaparvata lugens. The soil-rice-N. lugens system was treated with Zn2+ solution. Sugar content in rice was measured, and the reproduction and trehalose metabolism in N. lugens were assessed. The trehalase activity in rice significantly decreased at 100 mg center dot kg(-1) Zn2+, and the trehalose content increased. The glucose and starch content increased at higher Zn2+ concentrations. The fecundity and trehalose content of N. lugens decreased after feeding on zinc-stressed rice, and the glucose content in the high Zn2+ group was significantly higher than that in the low Zn2+ group. In addition, the soluble trehalase activity of N. lugens significantly decreased under the 125 mg center dot kg(-1) treatment, while the activity of membrane-bound trehalase significantly increased under the 150 mg center dot kg(-1) treatment. Quantitative RT-PCR indicated significantly lower expressions of NlTre1-1, NlTre2, and NITps after Zn treatment. In conclusion, Zn2+ treatment significantly altered the sugar content in rice plants; it also decreased the fecundity of N. lugens, which may be mediated by alterations in trehalose metabolism.

Automated summary

Excessive zinc is toxic to plants and its effect on the herbivorous insect Nilaparvata lugens is still unclear. This study assessed the impact of zinc-stressed rice plants on N. lugens. The results showed that zinc treatment altered sugar content in rice, reduced fecundity and trehalose content in N. lugens, and impacted trehalose metabolism. These findings suggest that zinc-stressed plants may have negative effects on herbivorous insects.