Spatio-temporal profiling of abscisic acid, indoleacetic acid and jasmonic acid in single rice seed during seed germination

Abstract

Abscisic acid (ABA), indoleacetic acid (IAA) and jasmonic acid (JA) are plant hormones that were reported to play indispensable roles during seed germination. However, the interactions between these plant hormones during rice seed germination have still not been explored clearly. A sensitive method for determination of these plant hormones would be beneficial for the exploration of such interactions. Herein, we present a liquid chromatography coupled with mass spectrometry (LC-MS) method for the quantification of ABA, IAA and JA in a single tissue of rice seed to investigate the spatio-temporal distribution of these plant hormones during rice seed germination. To this end, an in silico strategy was developed in order to select a derivatization reagent with an ideal sensitivity of MS detection. This strategy was confirmed with experimental studies on three reagents N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC), N,N-dimethylethylenediamine (DMED), and N-(acridin-9-yl)-2-bromoacetamide (AYBA) and their formic acid derivatives. Our results from the in silico and LC-MS experiments show that AYBA is a good derivatization reagent for ABA, IAA and JA due to its reasonable ionization efficiency in electrospray ionization mass spectrometry (ESI-MS) and excellent hydrophobicity. Finally, a sensitive LC-MS method upon AYBA was established for the determination of ABA, IAA and JA in germinated seeds. Good linearities for ABA, IAA, and JA were obtained with correlation coefficients greater than 0.99. The limits of detection (LODs) were in the range of 0.14-0.16 pg mL^-1. The method exhibits good precisions with RSD 1.5%-13.8% (intra-day) and 1.2%-7.3% (inter-day) and acceptable recoveries (88.6%-102.9%, n = 6). Finally, the method was successfully employed in the spatio-temporal profiling of ABA, IAA and JA in a single tissue of rice seed during rice seed germination.

Keywords: Density function theory; Derivatization reagents; LC-MS; Plant hormones; Spatio-temporal profiling.