Meng Xiangdong, Bonasera Jean M, Kim Jihyun F, Nissinen Riitta M, Beer Steven V
Department of Plant Pathology, Cornell University, Ithaca, NY 14853, USA.
Mol Plant Microbe Interact. 2006 Jan;19(1):53-61. doi: 10.1094/MPMI-19-0053.
The disease-specific (dsp) gene dspA/E of Erwinia amylovora encodes an essential pathogenicity effector of 198 kDa, which is critical to the development of the devastating plant disease fire blight. A yeast two-hybrid assay and in vitro protein pull-down assay demonstrated that DspA/E interacts physically and specifically with four similar putative leucine-rich repeat (LRR) receptor-like serine/threonine kinases (RLK) from apple, an important host of E. amylovora. The genes encoding these four DspA/E-interacting proteins of Malus xdomestica (DIPM1 to 4) are conserved in all genera of hosts of E. amylovora tested. They also are conserved in all cultivars of apple tested that range in susceptibility to fire blight from highly susceptible to highly resistant. The four DIPMs have been characterized, and they are expressed constitutively in host plants. In silico analysis indicated that the DIPMs have similar sequence structure and resemble LRR RLKs from other organisms. Evidence is presented for direct physical interaction between DspA/E and the apple proteins encoded by the four identified clones, which may act as susceptibility factors and be essential to disease development. Knowledge of DIPMs and the interaction with DspA/E thus may facilitate understanding of fire blight development and lead to new approaches to control of disease.
梨火疫病菌的致病特异性（dsp）基因dspA/E编码一种198 kDa的必需致病效应蛋白，这对毁灭性植物病害——火疫病的发生发展至关重要。酵母双杂交试验和体外蛋白下拉试验表明，DspA/E与来自苹果（梨火疫病菌的一种重要寄主）的四种类似的假定富含亮氨酸重复序列（LRR）的受体样丝氨酸/苏氨酸激酶（RLK）发生物理上的特异性相互作用。编码苹果（Malus xdomestica）这四种与DspA/E相互作用蛋白（DIPM1至4）的基因在所测试的梨火疫病菌所有寄主属中都是保守的。它们在所测试的所有苹果品种中也都是保守的，这些苹果品种对火疫病的易感性从高度易感到高度抗病不等。这四种DIPM蛋白已得到鉴定，它们在寄主植物中组成型表达。计算机分析表明，DIPM蛋白具有相似的序列结构，并且类似于来自其他生物体的LRR RLK。本文提供了DspA/E与四个已鉴定克隆所编码的苹果蛋白之间直接物理相互作用的证据，这些苹果蛋白可能作为感病因子，对病害发展至关重要。因此，了解DIPM蛋白以及它们与DspA/E的相互作用可能有助于理解火疫病的发生发展，并为病害防治带来新方法。
