Calendar Name: seminars
Scheduled for: Wednesday, July 7 2010, 11:00 - 12:30
Event text: Dr Yusuke Jikumaru
Growth Regulation Research Group
Plant Science Center, RIKEN Yokohama
JAPAN
"Establishment of a method for comprehensive plant
hormone analysis by LC-MS/MS"
Details: ABSTRACT
Current studies revealed that the hormonal regulations
were not always independent or parallel but rather often
synergistic or antagonistic. In order to better
understand their interactive networks, we have developed
a method for plant hormone analysis by using a liquid
chromatography-tandem mass spectrometry (LC-MS/MS). Our
objective is to establish a method for quantitative
analysis of as many hormones and related metabolites as
possible. A difficulty in this method is mainly
depending on their low concentrations in plants. Because
co-migrating impurities suppress ionization of target
compounds, it is necessary to establish a simple but
effective purification method before analysis by
LC-MS/MS. We will report our current status of hormone
analysis. Auxin-related compounds we analyze are
indole-3-acetic acid (IAA), indole-3-aldoxime,
indole-3-acetaldehyde, indole-3-acetamide and IAA-amino
acid conjugates. Cytokinins are trans-zeatin,
N6-(Δ2-isopentenyl)adenine, dihydrozeatin and their
3 ribosides. Abscisic acid (ABA) and its metabolites are
phaseic acid (PA), dihidro-PA, 7�-OH-ABA, neo-PA and
ABA-glycosyl ester (internal standards were kindly
provided by Dr. Suzanne Abrams). Gibberellins are GA1,
GA4 and other 12 GAs involved in GA1 and GA4
biosynthesis and metabolism. Jasmonic acid (JA) and
precursors are OPDA, OPC:8 and metabolites including
JA-Ile and 12-OH-JA. Salicylic acid has been analyzed
relatively easily. Brassinosteroids are still difficult
to analyze for now, and we can only detect castasterone.
We will report our current results of Arabidopsis dry
seeds, seedlings, leaves, roots and flowers. Minimum
amount of plant materials we need were depending on
concentrations of hormones. Usually we need
approximately 250 mg fresh weight of plant materials for
general hormone analysis. We can also extend the method
we established for Arabidopsis to other plants.
