title: Parthenolide and abscisic acid synthesis in feverfew are associated but environmental factors affect them dissimilarly.
abstract: The effect of harvest time, shading prior to harvest and water stress on parthenolide (PRT) concentration in feverfew and its possible connection with the abscisic acid (ABA) pathway were investigated. In plants harvested at different times of the day, acetumar the PRT levels were highest during late afternoon while ABA levels were greatest during morning hours. Shading plants during the afternoon prior to harvest caused a two-fold increase in ABA and no significant difference in PRT levels. ABA was higher in water-stressed plants while PRTcontent increased in plants following recovery from a water stress event. ABA inhibitors, norflurazon, sodium tungstate, naproxen and sodium bisulfite, were used to determine the connection between the biosynthesis of PRTand ABA. Norflurazon and naproxen reduced PRT concentration in cut flowers and in 2-month old plants. Sodium bisulfite and sodium tungstate reduced PRT only in cut flowers. Application of 2,4-D, a promoter of ABA synthesis, to potted plants resulted in a 2.5 fold increase in PRT levels. The inhibition of PRT formation in response to ABA inhibitors and the increase in PRT concentration observed with 2,4-D application indicated that PRT is derived from carotenoid synthesis similarly to ABA and not directly from farnesyl pyrosphosphate (FPP) as suggested for other sesquiterpene Lactones. However, PRT and ABA levels are affected dissimilarly by environmental conditions. The overall results of the study indicated that simple agricultural practices, such as harvesting during afternoon and subjecting plants to a single water stress event, can increase PRT concentration in the final feverfew product with no additional costs of production prior to harvest.
authors.affiliation: Department of Horticulture, Clemson University, Clemson, SC 29634-0375, USA. jfonseca@ag.arizona.edu
authors.forename: Jorge M
authors.initials: JM
authors.lastname: Fonseca
authors.forename: James W
authors.initials: JW
authors.lastname: Rushing
authors.forename: Nihal C
authors.initials: NC
authors.lastname: Rajapakse
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Thomas
authors.forename: Melissa B
authors.initials: MB
authors.lastname: Riley
mesh_terms: D000040:Abscisic Acid / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D002338:Carotenoids / Q000378:metabolism; D002940:Circadian Rhythm; D035264:Flowers / Q000737:chemistry; D008027:Light; D012717:Sesquiterpenes / Q000378:metabolism*; D020903:Tanacetum parthenium / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D014867:Water
chemical_list: D012717:Sesquiterpenes; D014867:Water; C002669:parthenolide; D002338:Carotenoids; D000040:Abscisic Acid