南京农业大学学报2012，Vol.35Issue(5)：113-124,12.
拟南芥韧皮部防卫反应转录调控与小麦抗蚜虫机制
Transcriptional regulation of Arabidopsis phloem-defenses as a paradigm to explore molecular mechinisam underlying wheat resistance to aphids
摘要
Abstract
Phloem-feeding insects are highly specialized in their mode of feeding and present a unique stress on plant fitness. These insects use their slender stylets to feed from a single-cell type,the phloem sieve element. In response,plants defend themselves by using the phloem-based defense ( PBD). A suggested PBD component is the lectin-type phloem protein (PP) , which may form high molecular weight polymers to close the sieve pores. An additional PBD component is the [3-1,3-glucan callose produced by glucan synthase( originally designated as glucan synthase-like, GSL) and accumulated on sieve plates. PP plugging and callose closure of sieve pores, and callose coagulation on sieve plates as well, is hypothesized to serve as a physical barrier to prevent the insects from phloem feeding. In general, plant defenses to insects are mediated by phytohormones ethylene and jasmonate, but whether both hormones have crosstalk with PBD is unclear. Therefore, the purposed study is to elucidate the regulation of PBD in wheat under attacks by aphids, which represent a typical group of phloem-feeding insects. Up to date,73 ,22 and 50 wheat genes of full length sequences respectively coding for MYB transcription factors, GSL enzymes and lectins or their receptors have been identified up to date, but their roles in PBD are unclear. To address the quenstion, studies could first include a transcriptional screening to identify MYB, lectin ( especially PP) and GSL genes involved in wheat PBD against aphids. Selected genes may be subjected to the pharmacological analysis to characterize their functions in association with ethylene or jasmonate signaling regulatory genes. Then,the defensive functions of identified genes could be confirmed by investigating effects of gene silencing and overexpression on aphid feeding and wheat defense responses. For overexpression,MYB,PP and GSL are pertinent to be linked with genes encoding green, yellow and red fluorescence proteins ( GFP, YFP and RFP) respectively, and the MYB-GFP fusion is further fused to the histidine tag (His)code. Next, fluorescent fusion proteins can be observed by laser confocal microscopy to visualize subcellular localizations supposed to be consistent with functions of the proteins in transgenic wheat. Gel mobility shift and chromatin immunoprecipitation assays could be devised to determine whether the MYB-GFP-His fusion protein, purified by His-affinitive nickel chromatography and present in the chromatin,binds the promoter and thus activates transcription of the PP,GSL or signaling regulatory gene. Overall, these studies can elucidate signaling and transcriptional regulation of wheat PBD against aphid attacks.关键词
植物韧皮部防卫反应/转录调控/信号传导Key words
plant phloem-based defenses/ transcriptional regulation/ signaling分类
农业科技引用本文复制引用
张春玲,付茂强,徐衡,董汉松..拟南芥韧皮部防卫反应转录调控与小麦抗蚜虫机制[J].南京农业大学学报,2012,35(5):113-124,12.基金项目
国家自然科学基金项目(30771441) （30771441）
国家转基因生物新品种培育重大专项(2009ZX08002-004B) （2009ZX08002-004B）
