Elliott Candace, Zhou Fasong, Spielmeyer Wolfgang, Panstruga Ralph, Schulze-Lefert Paul
The Sainsbury Laboratory, John Innes Centre, Norwich, United Kingdom.
Mol Plant Microbe Interact. 2002 Oct;15(10):1069-77. doi: 10.1094/MPMI.2002.15.10.1069.
Homologs of barley Mlo are found in syntenic positions in all three genomes of hexaploid bread wheat, Triticum aestivum, and in rice, Oryza sativa. Candidate wheat orthologs, designated TaMlo-A1, TaMlo-B1, and TaMlo-D1, encode three distinct but highly related proteins that are 88% identical to barley MLO and appear to originate from the three diploid ancestral genomes of wheat. TaMlo-B1 and the rice ortholog, OsMlo2, are able to complement powdery mildew-resistant barley mlo mutants at the single-cell level. Overexpression of TaMlo-B1 or barley Mlo leads to super-susceptibility to the appropriate powdery mildew formae speciales in both wild-type barley and wheat. Surprisingly, overexpression of either Mlo or TaMlo-B1 also mediates enhanced fungal development to tested inappropriate formae speciales. These results underline a regulatory role for MLO and its wheat and rice orthologs in a basal defense mechanism that can interfere with forma specialis resistance to powdery mildews.
在六倍体面包小麦（普通小麦）的所有三个基因组以及水稻（稻）中，大麦Mlo的同源基因都处于同线位置。候选小麦直系同源基因，命名为TaMlo - A1、TaMlo - B1和TaMlo - D1，编码三种不同但高度相关的蛋白质，它们与大麦MLO有88%的同一性，并且似乎源自小麦的三个二倍体祖先基因组。TaMlo - B1和水稻直系同源基因OsMlo2能够在单细胞水平上互补抗白粉病的大麦mlo突变体。TaMlo - B1或大麦Mlo的过表达导致野生型大麦和小麦对相应的白粉病菌生理小种超级敏感。令人惊讶的是，Mlo或TaMlo - B1的过表达还介导了对测试的不适当生理小种真菌发育的增强。这些结果强调了MLO及其小麦和水稻直系同源基因在一种基础防御机制中的调节作用，该机制可能会干扰生理小种对白粉病的抗性。
