Yamamizo Chihiro, Kuchimura Kazuo, Kobayashi Akira, Katou Shinpei, Kawakita Kazuhito, Jones Jonathan D G, Doke Noriyuki, Yoshioka Hirofumi
Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan.
Plant Physiol. 2006 Feb;140(2):681-92. doi: 10.1104/pp.105.074906. Epub 2006 Jan 11.
Late blight, caused by the notorious pathogen Phytophthora infestans, is a devastating disease of potato (Solanum tuberosum) and tomato (Solanum lycopersicum), and during the 1840s caused the Irish potato famine and over one million fatalities. Currently, grown potato cultivars lack adequate blight tolerance. Earlier cultivars bred for resistance used disease resistance genes that confer immunity only to some strains of the pathogen harboring corresponding avirulence gene. Specific resistance gene-mediated immunity and chemical controls are rapidly overcome in the field when new pathogen races arise through mutation, recombination, or migration from elsewhere. A mitogen-activated protein kinase (MAPK) cascade plays a pivotal role in plant innate immunity. Here we show that the transgenic potato plants that carry a constitutively active form of MAPK kinase driven by a pathogen-inducible promoter of potato showed high resistance to early blight pathogen Alternaria solani as well as P. infestans. The pathogen attack provoked defense-related MAPK activation followed by induction of NADPH oxidase gene expression, which is implicated in reactive oxygen species production, and resulted in hypersensitive response-like phenotype. We propose that enhancing disease resistance through altered regulation of plant defense mechanisms should be more durable and publicly acceptable than engineering overexpression of antimicrobial proteins.
晚疫病由臭名昭著的致病疫霉（Phytophthora infestans）引起，是马铃薯（Solanum tuberosum）和番茄（Solanum lycopersicum）的一种毁灭性病害，在19世纪40年代导致了爱尔兰马铃薯饥荒和超过一百万人死亡。目前，种植的马铃薯品种缺乏足够的晚疫病耐受性。早期培育的抗病品种使用的抗病基因仅对携带相应无毒基因的某些病原菌菌株具有免疫性。当新的病原菌小种通过突变、重组或从其他地方迁移产生时，特定抗性基因介导的免疫和化学防治措施在田间会迅速失效。丝裂原活化蛋白激酶（MAPK）级联在植物先天免疫中起关键作用。在此，我们表明，携带由马铃薯病原菌诱导型启动子驱动的组成型活性形式的MAPK激酶的转基因马铃薯植株对早疫病病原菌链格孢（Alternaria solani）以及致病疫霉均表现出高抗性。病原菌攻击引发了与防御相关的MAPK激活，随后诱导了NADPH氧化酶基因表达，这与活性氧的产生有关，并导致了类似过敏反应的表型。我们提出，通过改变植物防御机制的调控来增强抗病性应该比构建抗菌蛋白的过表达更持久且更容易被公众接受。
