Institution: | 1. Laboratory of Protein Engineering and Bioactive Molecules (LIP-MB), National Institute of Applied Sciences and Technology, INSAT, University of Carthage, Ministry of Higher Education and Scientific Research, Tunis Cedex 1080, Tunisia;2. Laboratory of Biotechnology Applied to Agriculture (LBAA), National Agricultural Research Institute of Tunisia, INRAT, University of Carthage, Ministry of Higher Education and Scientific Research, Tunis Cedex 2080, Tunisia;1. Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, United States of America;2. Department of Biology and Health Science, Hendrix College, Conway, AR, United States of America;3. Department of Biology, Miami University, Oxford, OH 45056, United States of America;1. Institute of Health and Environmental Ecology, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China;2. The Second School of Medicine, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China |
Abstract: | Nilaparvata lugens, the brown planthopper (BPH) feeds on rice phloem sap, containing high amounts of sucrose as a carbon source. Nutrients such as sugars in the digestive tract are incorporated into the body cavity via transporters with substrate selectivity. Eighteen sugar transporter genes of BPH (Nlst) were reported and three transporters have been functionally characterized. However, individual characteristics of NlST members associated with sugar transport remain poorly understood. Comparative gene expression analyses using oligo-microarray and quantitative RT-PCR revealed that the sugar transporter gene Nlst16 was markedly up-regulated during BPH feeding. Expression of Nlst16 was induced 2 h after BPH feeding on rice plants. Nlst16, mainly expressed in the midgut, appears to be involved in carbohydrate incorporation from the gut cavity into the hemolymph. Nlst1 (NlHT1), the most highly expressed sugar transporter gene in the midgut was not up-regulated during BPH feeding. The biochemical function of NlST16 was shown as facilitative glucose transport along gradients. Glucose uptake activity by NlST16 was higher than that of NlST1 in the Xenopus oocyte expression system. At least two NlST members are responsible for glucose uptake in the BPH midgut, suggesting that the midgut of BPH is equipped with various types of transporters having diversified manner for sugar uptake. |