盐胁迫对拟南芥和盐芥莲座叶芥子油苷含量的影响

芥子油苷是十字花科植物中一类含氮、含硫的次生代谢产物,与其水解产物在植物防御功能中有重要意义且与环境因子关系密切。以模式植物拟南芥（Arabidopsis thaliana）和盐生模式植物盐芥（Thellungiella halophila）为研究对象，系统地分析了盐胁迫下二者芥子油苷组成和含量的变化规律。拟南芥（生长4周）和盐芥（生长6周）叶片的芥子油苷组成在盐胁迫后没有改变。拟南芥的芥子油苷总量、脂肪族芥子油苷总量、吲哚族芥子油苷总量受盐胁迫的影响均不显著，而盐芥的则随盐胁迫增强先减少、后增加并高于对照水平。拟南芥脂肪族的3MSOP、5MSOP和吲哚族的4OHI3M、4MOI3M随盐胁迫增强而含量降低，而脂肪族的6MSOH、吲哚族的I3M以及盐芥脂肪族的3MSOP则随盐胁迫增强有含量增加的趋势。拟南芥脂肪族的8MSOO和吲哚族的1MOI3M，盐芥脂肪族的3MTP、Allyl、10MSD和吲哚族的4MOI3M，在盐胁迫下的含量变化与盐芥芥子油苷总量的变化趋势一致。

Effects of salt stress onglucosinolate contents in Arabidopsis thaliana and Thellungiella halophila rosette leaves

Glucosinolates are a group of plant secondary metabolites comprising at least 120 anionic thioglucosides with well-defined structures. Found in many members of the order Capparales, including important crops (e.g., oilseed rape, broccoli and cabbage), glucosinolates and their degradation products play important roles in plant defense and interactions with the environment. In the past decades, the importance of these nitrogen- and sulfur-containing plant secondary metabolites has become apparent due to their function as cancer-prevention agents, crop-protection compounds, and biofumigants in agriculture. In addition, the presence of glucosinolates in the model plant, Arabidopsis thaliana, has stimulated vigorous research efforts into these interesting amino acid-derived products. Here we report glucosinolate profiles in A. thaliana, a glycophyte, and its close relative Thellungiella halophila, a halophyte, under different salt stress conditions. Exposure of A. thaliana seedlings to 5-day salt stress led to chlorosis in young leaves under 50 mmol/L and 150 mmol/L NaCl, the latter exhibited stronger chlorosis phenotype. In contrast, T. halophila did not display obvious chlorosis under these conditions. It was clearly more tolerant to salt stress than A. thaliana. We then measured tissue water content and relative electrolyte leakage. NaCl treatment caused a significant decrease in tissue water content in A. thaliana, whereas it only caused a slight reduction in T. halophila. Relative conductivity, an indicator of membrane damage, was used to indicate electrolyte leakage. After a 5-day salt treatment, relative conductivity increased in both A. thaliana and T. halophila. However, the increase in A. thaliana was much higher than that in T. halophila. The composition of glucosinolates was not varied in the rosette leaves of four-week-old A. thaliana and 6-week-old T. halophila, which were irrigated with 50 mmol/L and 150 mmol/L NaCl. The contents of total, aromatic and indole glucosinolates were not varied significantly either. However, the contents of total, aromatic and indole glucosinolates decreased after 50 mmol/L NaCl treatment and increased after 150 mmol/L NaCl treatment. Aliphatic glucosinolates 3MSOP, 5MSOP and indole glucosinolates 4OHI3M and 4MOI3M in A. thaliana decreased with increasing NaCl concentrations, while aliphatic glucosinolates 6MSOH, indole glucosinolates I3M in A. thaliana and aliphatic glucosinolates 3MSOP in T. halophila increased with increasing NaCl concentrations. The contents of 8MSOO and 1MOI3M in A. thaliana, 3MTP, Allyl, 10MSD and 4MOI3M in T. halophila displayed a similar pattern of variation. Interestingly, only two glucosinolates were identified to be common in both A. thaliana and T. halophila, but they exhibited significantly different patterns in response to salt stress.