Production of 2-(2-phenylethyl)chromones in Aquilaria sinensis calli under different treatments

2-(2-Phenylethyl)chromones are main classes of aromatic compounds isolated from agarwood, the resinous portion derived from Aquilaria sinensis used as traditional medicine, incense and perfume. However, the mechanisms of biosynthesis of 2-(2-phenylethyl)chromones and agarwood formation are still unknown. Previous studies indicated that 6,7-dimethoxy-2-[2-(4-methoxyphenyl)ethyl]chromone (AH(8)) and 6,7-dimethoxy-2-(2-phenylethyl)chromone (AH(6)) were more sensitive to salt stress and can be used as markers to analyze the production of 2-(2-phenylethyl)chromones. In this study, the content of AH(6) and AH(8) was analyzed by an AB Sciex 5500 Qtrap mass spectrometer and the congeners of 2-(2-phenylethyl)chromones were detected by LC-DAD-IT-TOF-MS system in A. sinensis calli under various abiotic stresses and hormone treatments. Among the abiotic stresses, salt and drought stress remarkably increased the production of AH(6) and AH(8), and could induce 41 and 23 species of 2-(2-phenylethyl)chromones, respectively. However, cold treatment has little influence on the production of 2-(2-phenylethyl)chromones. Ion stresses induced by KNO3, CaCl2, and (NH4)(2)SO4 also significantly increased the content of AH(6) and AH(8), and could induced 14, 18, and 14 congeners of 2-(2-phenylethyl)chromones, respectively. Exogenous hormones including MeJA, SA and ABA induced a small amount of 2-(2-phenylethyl)chromones in calli within 20 days, while 6, 5, and 7 species of 2-(2-phenylethyl)chromones were detected after MeJA, SA and ABA treatment, respectively. Our study would provide solid basis for further research on biosynthesis of 2-(2-phenylethyl)chromones and agarwood formation.