Contribution of ethylene biosynthesis for resistance to blast fungus infection in young rice plants
Contribution of ethylene biosynthesis for resistance to blast fungus infection in young rice plants
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DOI：
10.1104/pp.106.085258
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发表时间：
2006-11-01
期刊：
影响因子：
7.4
通讯作者：
Ohashi, Yuko
中科院分区：
文献类型：
--
作者：
Iwai, Takayoshi;Miyasaka, Atsushi;Ohashi, Yuko
乙烯（ET）在水稻抗稻瘟病菌侵染中的作用尚不清楚。为了研究它，我们量化了ET水平接种后，使用水稻品种日本晴（野生型）的四叶期的水稻幼苗和它的同基因植物（IL 7），其中含有Pi-i抗性基因稻瘟病真菌种族003。过敏反应（HR）的小坏死病变形成于接种后42至72小时（hpi）在抗性IL 7叶片，和白色扩大病变在96 hpi在敏感的野生型叶片。值得注意的是增强ET排放在48 hpi伴随着增加的1-氨基环丙烷-1-羧酸（ACC）水平和高度升高的ACC氧化酶（ACO）活性在IL 7叶，而只有增强ACC增加在96 hpi在野生型叶。在水稻基因组中发现的6个ACC合酶（ACS）和7个ACO基因中，OsACS 2在IL 7中在48 hpi瞬时表达，在野生型中在96 hpi瞬时表达，OsAC 07在IL 7中在48 hpi瞬时表达。用ACS抑制剂氨氧乙酸治疗，抑制IL 7在48 hpi时增强的ET发射，导致扩大的病变而不是HR病变。外源性ACC损害了氨基氧乙酸诱导的IL 7耐药性的破坏，用1-甲基环丙烯和硫代硫酸银（ET作用的抑制剂）治疗并不能抑制耐药性。这些研究结果表明ET生物合成的重要性，因此，副产品，氰化物，HR伴随的抗稻瘟病在年轻的水稻植株和诱导OsACS 2和OsACO 7基因表达的贡献。
The role of ethylene ( ET) in resistance to infection with blast fungus (Magnaporthe grisea) in rice ( Oryza sativa) is poorly understood. To study it, we quantified ET levels after inoculation, using young rice plants at the four-leaf stage of rice cv Nipponbare ( wild type) and its isogenic plant (IL7), which contains the Pi-i resistance gene to blast fungus race 003. Small necrotic lesions by hypersensitive reaction (HR) were formed at 42 to 72 h postinoculation (hpi) in resistant IL7 leaves, and whitish expanding lesions at 96 hpi in susceptible wild-type leaves. Notable was the enhanced ET emission at 48 hpi accompanied by increased 1-aminocyclopropane-1-carboxylic acid (ACC) levels and highly elevated ACC oxidase (ACO) activity in IL7 leaves, whereas only an enhanced ACC increase at 96 hpi in wild-type leaves. Among six ACC synthase (ACS) and seven ACO genes found in the rice genome, OsACS2 was transiently expressed at 48 hpi in IL7 and at 96 hpi in wild type, and OsACO7 was expressed at 48 hpi in IL7. Treatment with an inhibitor for ACS, aminooxyacetic acid, suppressed enhanced ET emission at 48 hpi in IL7, resulting in expanding lesions instead of HR lesions. Exogenously supplied ACC compromised the aminooxyacetic acid-induced breakdown of resistance in IL7, and treatment with 1-methylcyclopropene and silver thiosulfate, inhibitors of ET action, did not suppress resistance. These findings suggest the importance of ET biosynthesis and, consequently, the coproduct, cyanide, for HR-accompanied resistance to blast fungus in young rice plants and the contribution of induced OsACS2 and OsACO7 gene expression to it.