Heitz T, Bergey D R, Ryan C A
Institute of Biological Chemistry, Washington State University, Pullman 99164-6340 USA.
Plant Physiol. 1997 Jul;114(3):1085-93. doi: 10.1104/pp.114.3.1085.
We investigated the relationship between the expression of lipoxygenase (LOX) genes and the systemin-dependent wound response in tomato (Lycopersicon esculentum) leaves. A polymerase chain reaction-based approach was used to isolate two tomato Lox cDNAs, called TomLoxC and TomLoxD. Both TomLOXC and TomLOXD amino acid sequences possess an N-terminal extension of about 60 residues that were shown by in vitro uptake to function as transit peptides, targeting these proteins into the chloroplast. Within 30 to 50 min following wounding or systemin or methyl jasmonate treatments, the TomLoxD mRNA level increased and reached a maximum between 1 and 2 h. TomLoxC mRNA was not detectable in leaves and was not found following wounding, but it was found in ripening fruits, indicating that the two tomato Lox genes are regulated in different tissues by different processes. The results suggest that the TomLoxD gene is up-regulated in leaves in response to wounding and encodes a chloroplast LOX that may play a role as a component of the octadecanoid defense-signaling pathway.
我们研究了番茄（Lycopersicon esculentum）叶片中脂氧合酶（LOX）基因的表达与系统素依赖性伤口反应之间的关系。采用基于聚合酶链反应的方法分离出两个番茄Lox cDNA，分别称为TomLoxC和TomLoxD。TomLOXC和TomLOXD的氨基酸序列都有一个约60个残基的N端延伸，体外摄取实验表明该延伸作为转运肽发挥作用，将这些蛋白质靶向导入叶绿体。在受伤、用系统素或茉莉酸甲酯处理后的30至50分钟内，TomLoxD mRNA水平升高，并在1至2小时内达到最大值。在叶片中未检测到TomLoxC mRNA，受伤后也未发现，但在成熟果实中发现了它，这表明两个番茄Lox基因在不同组织中受不同过程的调控。结果表明，TomLoxD基因在叶片中因受伤而上调，编码一种叶绿体LOX，可能作为十八碳酸防御信号通路的一个组成部分发挥作用。
