生物谷报道：日本名古屋大学科学家日前发现一种名为“ＳＩＰＫ”的蛋白激酶，它可控制植物的免疫反应。
据日本媒体１日报道，名古屋大学科学家吉冈博文等人在最新一期美国植物生理学会的《植物细胞》杂志上撰文指出，病原菌一旦侵入植物细胞内，植物会生成活性氧和活性氮。以此为信号，植物体内发生各种免疫反应以抗击病原菌。欧美科学家发现，控制植物免疫反应过程的应该是与这一过程有关联的特殊酶集合体，但是具体控制这一过程的酶一直未被确定。为了找到这种酶，吉冈博文等人对这种特殊酶集合体进行了仔细研究。
科学家首先将病原菌注入植物细胞内，再利用基因技术逐个抑制特殊酶集合体中的每种酶。结果显示，当抑制蛋白激酶“ＳＩＰＫ”时，植物活性氧和活性氮生成速度大大放慢，从而导致植物体内免疫反应非常不明显。科学家因此认定，“ＳＩＰＫ”是控制植物免疫反应的酶。
吉冈博文等人在这一发现的基础上研制出一种体内“ＳＩＰＫ”非常活跃的马铃薯，而活跃的“ＳＩＰＫ”使马铃薯抗病能力大大增强。科学家计划今后利用这一成果研制出更多抗病能力很强的蔬菜。（新华网）
生物谷推荐原始出处：
Plant Cell Advance Online Publication
Published on May 30, 2008; 10.1105/tpc.107.055855
Received September 25, 2007
Returned for revision April 13, 2008
Accepted May 7, 2008
MAPK Signaling Regulates Nitric Oxide and NADPH Oxidase-Dependent Oxidative Bursts in Nicotiana benthamiana
Shuta Asai 1, Kohji Ohta 2, and Hirofumi Yoshioka 1*
1 Laboratory of Defense in Plant–Pathogen Interactions, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya 464-8601, Japan
2 Plant Pathology Laboratory, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
* To whom correspondence should be addressed. E-mail: hyoshiok@agr.nagoya-u.ac.jp .
Nitric oxide (NO) and reactive oxygen species (ROS) act as signals in innate immunity in plants. The radical burst is induced by INF1 elicitin, produced by the oomycete pathogen Phytophthora infestans. NO ASSOCIATED1 (NOA1) and NADPH oxidase participate in the radical burst. Here, we show that mitogen-activated protein kinase (MAPK) cascades MEK2-SIPK/NTF4 and MEK1-NTF6 participate in the regulation of the radical burst. NO generation was induced by conditional activation of SIPK/NTF4, but not by NTF6, in Nicotiana benthamiana leaves. INF1- and SIPK/NTF4-mediated NO bursts were compromised by the knockdown of NOA1. However, ROS generation was induced by either SIPK/NTF4 or NTF6. INF1- and MAPK-mediated ROS generation was eliminated by silencing Respiratory Burst Oxidase Homolog B (RBOHB), an inducible form of the NADPH oxidase. INF1-induced expression of RBOHB was compromised in SIPK/NTF4/NTF6-silenced leaves. These results indicated that INF1 regulates NOA1-mediated NO and RBOHB-dependent ROS generation through MAPK cascades. NOA1 silencing induced high susceptibility to Colletotrichum orbiculare but not to P. infestans; conversely, RBOHB silencing decreased resistance to P. infestans but not to C. orbiculare. These results indicate that the effects of the radical burst on the defense response appear to be diverse in plant–pathogen interactions.
