Christensen Anders B, Thordal-Christensen Hans, Zimmermann Grit, Gjetting Torben, Lyngkjaer Michael F, Dudler Robert, Schweizer Patrick
Risø National Laboratory, Frederiksborgvej 399, P.O. 49, DK-4000 Roskilde, Denmark.
Mol Plant Microbe Interact. 2004 Jan;17(1):109-17. doi: 10.1094/MPMI.2004.17.1.109.
Germinlike proteins (GLP) are encoded in plants by a gene family with proposed functions in plant development and defense. Genes of GLP subfamily 4 of barley (HvGLP4, formerly referred to as HvOxOLP) and the wheat orthologue TaGLP4 (formerly referred to as TaGLP2a) were previously found to be expressed in pathogen-attacked epidermal tissue of barley and wheat leaves, and the corresponding proteins are proposed to accumulate in the apoplast. Here, the role of HvGLP4 and TaGLP4 in the defense of barley and wheat against Blumeria graminis (DC.) E. O. Speer, the cereal powdery mildew fungus, was examined in an epidermal transient expression system and in transgenic Arabidopsis thaliana plants overexpressing His-tagged HvGLP4. Leaf extracts of transgenic Arabidopsis overexpressing HvGLP4 contained a novel His-tagged protein with superoxide dismutase activity and HvGLP4 epitopes. Transient overexpression of TaGLP4 and HvGLP4 enhanced resistance against B. graminis in wheat and barley, whereas transient silencing by RNA interference reduced basal resistance in both cereals. The effect of GLP4 overexpression or silencing was strongly influenced by the genotype of the plant. The data suggest that members of GLP subfamily 4 are components of quantitative resistance in both barley and wheat, acting together with other, as yet unknown, plant components.
类萌发素蛋白（GLP）在植物中由一个基因家族编码，该家族在植物发育和防御中具有特定功能。此前发现，大麦GLP亚家族4的基因（HvGLP4，以前称为HvOxOLP）和小麦同源基因TaGLP4（以前称为TaGLP2a）在大麦和小麦叶片受病原体攻击的表皮组织中表达，并且相应的蛋白质被认为在质外体中积累。在此，通过表皮瞬时表达系统以及在过表达His标签的HvGLP4的转基因拟南芥植物中，研究了HvGLP4和TaGLP4在大麦和小麦抵御禾本科布氏白粉菌（DC.）E.O. Speer的防御作用。过表达HvGLP4的转基因拟南芥的叶片提取物含有一种具有超氧化物歧化酶活性且带有HvGLP4表位的新型His标签蛋白。TaGLP4和HvGLP4的瞬时过表达增强了小麦和大麦对禾本科布氏白粉菌的抗性，而通过RNA干扰进行的瞬时沉默降低了两种谷物的基础抗性。GLP4过表达或沉默的效果受到植物基因型的强烈影响。数据表明，GLP亚家族4的成员是大麦和小麦中数量抗性的组成部分，与其他尚未明确的植物成分共同发挥作用。
