TITLE:
Stress Responses of Peanut (Arachis hypogaea L.) Genotypes as Measured by Trigonelline Content after Exposure to UV-B Radiation
AUTHORS:
David Willmon, Amith R. Devireddy, Madhuri Inupakutika, Naveen Puppala, Youngkoo Cho
KEYWORDS:
Abiotic Stress, Arachis hypogaea L., Trigonelline, UV-B
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.5,
April
20,
2017
ABSTRACT: UV-B radiation has been
widely documented as a stressor for plants that can cause decreased biomass,
reduction in photosynthesis, and oxidative stress. Trigonelline is a secondary
metabolite that is biosynthesized in some plants in response to abiotic stress
such as UV-B irradiation. The objectives of this study were to examine
biochemical stress responses for peanut plants (Arachis hypogaea L.) of four different genotypes (Spanish, Valencia, Virginia, and Runner) after exposure at various lengths to UV-B radiation and to examine the
alteration of trigonelline biosynthesis due to the age of the plants. Peanut
plants from the genotypes were exposed to UV-B radiation at three exposure
times (60, 120, and 180 min); plants from two growth stages, the flowering (R1)
and early maturity (R7), were used. Significant positive correlations (rs 0.29-0.74, P≤0.05)
were found for trigonelline concentrations and UV-B exposure times. With longer
exposure times of 180 min for plants at R7, trigonelline biosynthesis began as
early as 10 days after treatment with 154.6 μg·g-1 DW and
remained or increased by up to 71.5 μg·g-1 DW (46.3%) throughout the sampling intervals (10, 20, 30, 40, and 50
days after treatment) to a final value of 226.1 μg·g-1 DW.
All four genotypes at R7 exhibited trigonelline concentrations 47.3% to 52.4%
(71.6 to 96.5 μg·g-1 DW) higher than individuals at R1. Trigonelline biosynthesis at R7 was
significantly (PPP