cDNA Cloning and characterization of jasmonic acid-responsive genes in suspension-cultured rice cells

植物对病原体如真菌、细菌和病毒的防御反应涉及被称为植物抗毒素的低分子量化合物的诱导合成。生物诱导子是一类来源于病原微生物和寄主植物细胞表面的生物诱导子，可诱导植物的防御反应。一般认为，诱导子分子与植物膜受体结合，复合物激活一系列特定基因，导致植物抗毒素的合成。我们已经提出，茉莉酸功能作为一个信号转导诱导的植物抗毒素momilactone A的生物合成的诱导剂N-乙酰壳七糖在悬浮培养的水稻细胞。为了研究茉莉酸在水稻细胞中的作用方式，我们尝试了茉莉酸反应基因的cDNA克隆。从水稻悬浮培养细胞中制备cDNA文库，通过差异筛选，获得了3个cDNA克隆（cRRJ 1、cEEJ 2和cRRJ 4）和1个cDNA克隆（cRERJ 1）， ...更多信息 分别用10-4 M外消旋茉莉酸处理2小时和30分钟。RRJ 1编码与催化含硫氨基酸合成或代谢的酶同源的推定多肽。RRJ 2编码一个与水稻和玉米丙酮酸脱羧酶高度同源的多肽，可能与水稻细胞在厌氧条件下获得能量有关。RRJ 4推测的多肽与老黄酶超家族成员同源，但其生物学功能尚不清楚。RERJ 1编码一种推定的多肽，其在羧基末端附近含有碱性区/螺旋-环-螺旋（bHLH）结构域。由于bHLH蛋白是一种普遍存在的转录因子，在所有的真核生物中都存在，因此RERJ 1可能在茉莉酸的信号转导途径中发挥重要作用。这是第一个信息的转录因子基因的存在是响应茉莉酸。少

Plant defense reactions against pathogens such as fungi, bacteria, and viruses involve induced synthesis of low molecular weight compounds called phytoalexins. Biotic elicitors which are derived from the cell surface of pathogenic microbes as well as host plants tRIgger the defense response. It is considered that an elicitor molecule is combined with a plant membrane receptor, and that the complex activates a series of specific genes, resulting in the synthesis of phytoalexins. We have suggested that jasmonic acid functions as a signal transducer in the induction of biosynthesis of the phytoalexin momilactone A by the elicitor N-acetylchitoheptaose in suspension-cultured rice cells. To investigate mode of action of jasmonic acid in the rice cells, we attempted cDNA cloning of jasmonic acidresponsive genes. Three cDNA clones ( cRRJ1, cEEJ2, and cRRJ4 ) and one cDNA clone ( cRERJ1 ) were isolated by differential screening of cDNA libraries prepared from suspensioned-cultured rice cells t … More reated with 10-4 M of racemic jasmonic acid for 2 hours and 30 minutes, respectively. RRJ1 encodes a putative polypeptide that is homologous to enzymes catalyzing synthesis or metabolism of sulful-containing amino acids. RRJ2 encodes a putative polypeptide that is highly homologous to pyrvate decarboxylases from rice and maize, and probably contributes to aquirement of energy in rice cells under the anairoic condition. The putative polypeptide by RRJ4 is homelogous to members of old yellow enzyme superfamily biological functions of which remains to be clarified. RERJ1 encodes a putative polypeptide that contains a basic region/helix-loop-helix ( bHLH ) domain near the carboxyl terminus. Since bHLH proteins are ubiquitous transcription factors that have been found virtually all eukaryotes examined to date, RERJ1 might play one of important roles in the signal transduction pathway of jasmonic acid in he suspension-cultured cells. This is the first information on the presence of a transcription factor gene that is responsive to jasmonic acid. Less