title: Metabolite analyses of grain from maize hybrids grown in the United States under drought and watered conditions during the 2002 field season.
abstract: Understanding natural variation in the composition of conventional crop germplasms is critical in establishing a baseline for comparison of biotechnology-derived crops. This is particularly relevant to such traits as tolerance to drought stress. Thus, there is both a need to understand the contribution of stress conditions to natural variation in plant nutritional components and to determine whether levels of small molecule metabolites such as osmoprotectants and stress metabolites are also affected. As a first step in developing such information for maize, seven conventional hybrids were grown under different moisture regimens and the impact of moisture on composition was assessed. The regimens included well-watered conditions, water restriction during the vegetative phase, and water restriction during grain fill. Compositional analyses of the harvested grain included assessments of the levels of proximates (moisture, protein, oil, starch) and small molecule metabolites such as fatty acids, free amino acids, organic acids, sugars, total glycerol, glycine betaine, and abscisic acid. Ranges for these analytes were determined across all moisture regimens, and the effect of the different water regimens on these analytes was also evaluated. The number and type of grain analytes that showed statistically significant differences in levels between different water regimens differed quite markedly by maize hybrid. However, the magnitude of mean differences between well-watered and water-restricted samples was typically small, and statistically significant differences for any given analyte were typically observed in only one to three of the seven maize hybrids. Only two analytes, free glutamine and free proline, showed a significant drought-induced difference in at least four maize hybrids.
authors.affiliation: Product Safety Center, Crop Analytics, and Regulatory Affairs, Monsanto Company, 800 North Lindbergh Boulevard, St. Louis, Missouri 63167, USA. george.g.harrigan@monsanto.com
authors.forename: George G
authors.initials: GG
authors.lastname: Harrigan
authors.forename: Leanna G
authors.initials: LG
authors.lastname: Stork
authors.forename: Susan G
authors.initials: SG
authors.lastname: Riordan
authors.forename: William P
authors.initials: WP
authors.lastname: Ridley
authors.forename: Susan
authors.initials: S
authors.lastname: Macisaac
authors.forename: Steven C
authors.initials: SC
authors.lastname: Halls
authors.forename: Robert
authors.initials: R
authors.lastname: Orth
authors.forename: Diane
authors.initials: D
authors.lastname: Rau
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Smith
authors.forename: Li
authors.initials: L
authors.lastname: Wen
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Brown
authors.forename: Rochelle
authors.initials: R
authors.lastname: Riley
authors.forename: Dayong
authors.initials: D
authors.lastname: Sun
authors.forename: Steven
authors.initials: S
authors.lastname: Modiano
authors.forename: Todd
authors.initials: T
authors.lastname: Pester
authors.forename: Adrian
authors.initials: A
authors.lastname: Lund
authors.forename: Donald
authors.initials: D
authors.lastname: Nelson
mesh_terms: D002241:Carbohydrates / Q000032:analysis; D004190:Disasters; D006824:Hybridization, Genetic; D012621:Seasons; D012639:Seeds / Q000737:chemistry*; D014481:United States; D014867:Water; D003313:Zea mays / Q000737:chemistry* / Q000254:growth & development*
chemical_list: D002241:Carbohydrates; D014867:Water