Functional genomics of leaf epidermis in response to pathogen attack.

植物病害每年都会对农业生产和食物供应造成毁灭性的影响。然而，在病原体侵袭期间，大多数植物都会采取一系列的物理和化学防御策略来抵御企图入侵。在植物表面(表皮)，病原体感染失败通常与试图侵入的部位下面的局部寄主细胞壁防御工事(乳突)有关。长期以来，乳头形成一直被认为是一种古老的植物对病原体侵入企图的抵抗。因此，人们致力于了解入侵的机制。我以前的研究表明，一种有效的、白粉病侵染后小麦叶表皮侵染部位的近免疫穿透抗性。从这些材料中，我们分离了约3,000个表皮基因，其中许多基因的特征是显示了在病原菌侵袭的早期阶段启动的广泛的遗传防御。拟议的研究将集中在一个具有良好特性的小麦白粉病病理系统和一个新的拟南芥-炭疽菌病理系统之间的比较和互补分析，以解决表皮穿透抗性的基本问题。总体战略将包括：1)小麦叶片表皮中介导穿透抗性的一整套核心元件的分子分离、鉴定和功能鉴定。2)以拟南芥为模式植物，进行表皮层抗性的遗传确认和调控。这项研究涉及病原学、分子和基因组学方法的使用。这项研究的成功完成将极大地有助于我们理解控制叶表皮早期防御的遗传和细胞机制，研究成果可能会为工程植物抗病创造新的策略。

Plant diseases have a devastating impact on agricultural production and food supply every year.  During pathogen attack however, most plants mount a complex of physical and chemical defence strategies to ward off attempted invasions.  On the plant surface (epidermis), pathogen infection failures are often associated with localized host cell wall fortifications (papillae) underneath the sites of attempted penetration.  Papilla formation has long been recognized as an ancient, basal plant resistance to pathogen penetration attempts.  Hence, major efforts have been devoted to understanding the mechanisms of penetration resistance.  My previous studies have shown an effective, near-immune penetration resistance at attempted penetration sites on wheat leaf epidermis following attack by the powdery mildew fungus.  From this material, we have isolated ~3,000 epidermal genes, many of which we have characterized to show a broad repertoire of genetic defenses unleashed during the early stage of pathogen attack.  The proposed research will focus on comparative and complementary analyses between a well-characterized wheat-powdery mildew pathosystem and a novel Arabidopsis-Colletotrichum pathosystem to address fundamental questions in epidermal penetration resistance.  The overall strategy will involve i) the molecular isolation, identification and functional characterization of a full set of core elements in wheat leaf epidermis that mediate penetration resistance, and ii) genetic confirmation and manipulation of epidermal resistance using Arabidopsis as a model plant.  This research involves the use of pathogenic, molecular and genomic methods.  Successful completion of this study will contribute tremendously to our understanding of the genetic and cellular mechanisms that control early defenses in the leaf epidermis, and the output of the research could generate new strategies for engineering plant disease resistance.