荻草谷网蚜是一种在中国温带地区对小麦作物最具破坏性的蚜虫。但是关于这种蚜虫的遗传结构以及不同地理位置对种群的影响却知之甚少。在本研究中，我们通过使用一个线粒体基因COI，一个核基因EF-1α，以及两个内共生菌布赫纳氏菌基因gnd和trpA分析了中国18个地理种群，从而研究了荻草谷网蚜的种群遗传结构和种群历史动态。各群体的数据分析显示单倍型多样性高，核苷酸变异低。SAMOVA分析没有发现遗传距离和地理距离之间的相关性。然而，种群多样性较高的地区具有较高的单倍型多样性。因此，我们推测，在中国荻草谷网蚜的自然迁移途径主要有两条。一条路径是从云南到四川盆地，另外一条是从武汉、信阳、胶东半岛地区到西北地区。基于这一假设，我们推断这些蚜虫首先出现在西南和南部地区，并在东南和西南季风的帮助下于春夏季在北方发生。秋季，蚜虫随东北和西北季风向南扩散。

Cereal aphids are major insect pests of wheat, which cause significant damages to wheat production.  Previous studies mainly focused on the resistance of different wheat varieties to one specific aphid species.  However, reports on the physiology and defense responses of wheat to different cereal aphids are basically lacking.  In this work, we studied the feeding behavior of three cereal aphids: the grain aphid, Sitobion avenae (Fabricius), the greenbugs, Schizaphis graminum (Rondani), and the bird cherry-oat aphid, Rhopalosiphum padi (Linnaeus) on winter wheat, and the physiology and defense responses of wheat to the infestation of these cereal aphids with focus on how these cereal aphids utilize divergent strategies to optimize their nutrition requirement from wheat leaves.  Our results indicated that S. graminum and R. padi were better adapted to penetrating phloem tissue and to collect more nutrition than S. avenae.  The harm on wheat physiology committed by S. graminum and R. padi was severer than that by S. avenae, through reducing chlorophyll concentration and interfering metabolism genes.  Furthermore, cereal aphids manipulated the plant nutrition metabolism by increasing the relative concentration of major amino acids and percentage of essential amino acids.  In addition, different cereal aphids triggered specific defense response in wheat.  All of these results suggested that different cereal aphids utilize divergent strategies to change the physiological and defense responses of their host plants in order to optimize their nutrition absorption and requirement.  These findings not only extend our current knowledge on the insect–plant interactions but also provide useful clues to develop novel biotechnological strategies for enhancing the resistance and tolerance of crop plants against phloem-feeding insects.

Long-chain acyl-Coenzyme A (CoA) synthetases (LACSs) catalyze the formation of long-chain acyl-CoA, and play important roles in fatty acid metabolism including phospholipids, triacylglycerol (TAG) biosynthesis and fatty acid β-oxidation. Here, we report the characterization of a LACS gene from Brassica napus. It is highly homologous to Arabidopsis LACS4 and thus designated as BnLACS4. The cloned gene BnLACS4 could complement a LACS-deficient yeast strain YB525. It is mainly expressed in flowers and developing seeds where lipid biosynthesis is at high rate in Brassica napus. When transiently expressed in tobacco leaves, BnLACS4 is localized in endoplasmic reticulum (ER), the common site for eukaryotic pathway of lipid biosynthesis. Expression of BnLACS4 in the yeast strain pep4 increased its lipid content. Taken together, our results suggest that BnLACS4 may be involved in lipid biosynthesis in B. napus.