Multi-imaging of Cytokinin and Abscisic Acid on the Roots of Rice (Oryza sativa) Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

• Published in: Journal of agricultural and food chemistry 2017-09, Vol.65 (35), p.7624-7628
• Main Authors: Shiono, Katsuhiro, Hashizaki, Riho, Nakanishi, Toyofumi, Sakai, Tatsuko, Yamamoto, Takushi, Ogata, Koretsugu, Harada, Ken-ichi, Ohtani, Hajime, Katano, Hajime, Taira, Shu
• Format: Article
• Language: English
• Subjects: Abscisic Acid - metabolism; Biological Transport; Cytokinins - metabolism; Oryza - chemistry; Oryza - metabolism; Plant Growth Regulators - metabolism; Plant Roots - chemistry; Plant Roots - metabolism; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.7b02255

Plant hormones act as important signaling molecules that regulate responses to abiotic stress as well as plant growth and development. Because their concentrations of hormones control the physiological responses in the target tissue, it is important to know the distributions and concentrations in the tissues. However, it is difficult to determine the hormone concentration on the plant tissue as a result of the limitations of conventional methods. Here, we report the first multi-imaging of two plant hormones, one of cytokinin [i.e., trans-zeatin (tZ)] and abscisic acid (ABA) using a new technology, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOF–MS) imaging. Protonated signals of tZ (m/z 220.1) and ABA (m/z 265.3) were chosen on longitudinal sections of rice roots for MS imaging. tZ was broadly distributed about 40 mm behind the root apex but was barely detectable at the apex, whereas ABA was mainly detected at the root apex. Multi-imaging using MALDI–TOF–MS enabled the visualization of the localization and quantification of plant hormones. Thus, this tool is applicable to a wide range of plant species growing under various environmental conditions.