Ribnicky DM, Shulaev V, Raskin I
Biotech Center, Foran Hall, Cook College, Rutgers University, 59 Dudley Road, New Brunswick, New Jersey 08901-8520, USA.
Plant Physiol. 1998 Oct;118(2):565-72. doi: 10.1104/pp.118.2.565.
Salicylic acid (SA) is an important component of systemic-acquired resistance in plants. It is synthesized from benzoic acid (BA) as part of the phenylpropanoid pathway. Benzaldehyde (BD), a potential intermediate of this pathway, was found in healthy and tobacco mosaic virus (TMV)-inoculated tobacco (Nicotiana tabacum L. cv Xanthi-nc) leaf tissue at 100 ng/g fresh weight concentrations as measured by gas chromatography-mass spectrometry. BD was also emitted as a volatile organic compound from tobacco tissues. Application of gaseous BD to plants enclosed in jars caused a 13-fold increase in SA concentration, induced the accumulation of the pathogenesis-related transcript PR-1, and increased the resistance of tobacco to TMV inoculation. [13C6]BD and [2H5]benzyl alcohol were converted to BA and SA. Labeling experiments using [13C1]Phe in temperature-shifted plants inoculated with the TMV showed high enrichment of cinnamic acids (72%), BA (34%), and SA (55%). The endogenous BD, however, contained nondetectable enrichment, suggesting that BD was not the intermediate between cinnamic acid and BA. These results show that BD and benzyl alcohol promote SA accumulation and expression of defense responses in tobacco, and provide insight into the early steps of SA biosynthesis.
水杨酸（SA）是植物系统获得性抗性的重要组成部分。它是由苯甲酸（BA）作为苯丙烷类途径的一部分合成的。通过气相色谱 - 质谱法测定，在健康的和接种烟草花叶病毒（TMV）的烟草（烟草品种Xanthi - nc）叶片组织中发现苯甲醛（BD）作为该途径的潜在中间体，其浓度为100 ng/g鲜重。BD也作为挥发性有机化合物从烟草组织中释放出来。将气态BD施用于封闭在罐中的植物会使SA浓度增加13倍，诱导病程相关转录本PR - 1的积累，并增强烟草对TMV接种的抗性。[13C6]BD和[2H5]苯甲醇被转化为BA和SA。在接种TMV的温度转换植物中使用[13C1]苯丙氨酸进行标记实验表明，肉桂酸（72%）、BA（34%）和SA（55%）高度富集。然而，内源性BD未检测到富集，这表明BD不是肉桂酸和BA之间的中间体。这些结果表明，BD和苯甲醇促进烟草中SA的积累和防御反应的表达，并为SA生物合成的早期步骤提供了见解。
