title: Understanding abiotic stress tolerance mechanisms in soybean: a comparative evaluation of soybean response to drought and flooding stress.
abstract: Many sources of drought and flooding tolerance have been identified in soybean, however underlying molecular and physiological mechanisms are poorly understood. Therefore, it is important to illuminate different plant responses to these abiotic stresses and understand the mechanisms that confer tolerance. Towards this goal we used four contrasting soybean (Glycine max) genotypes (PI 567690--drought tolerant, Pana--drought susceptible, PI 408105A--flooding tolerant, S99-2281--flooding susceptible) grown under greenhouse conditions and compared genotypic responses to drought and flooding at the physiological, biochemical, and cellular level. We also quantified these variations and tried to infer their role in drought and flooding tolerance in soybean. Our results revealed that different mechanisms contribute to reduction in net photosynthesis under drought and flooding stress. Under drought stress, ABA and stomatal conductance are responsible for reduced photosynthetic rate; while under flooding stress, accumulation of starch granules played a major role. Drought tolerant genotypes PI 567690 and PI 408105A had higher plastoglobule numbers than the susceptible Pana and S99-2281. Drought stress increased the number and size of plastoglobules in most of the genotypes pointing to a possible role in stress tolerance. Interestingly, there were seven fibrillin proteins localized within the plastoglobules that were up-regulated in the drought and flooding tolerant genotypes PI 567690 and PI 408105A, respectively, but down-regulated in the drought susceptible genotype Pana. These results suggest a potential role of Fibrillin proteins, FBN1a, 1b and 7a in soybean response to drought and flooding stress.
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Raymond N
authors.initials: RN
authors.lastname: Mutava
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Silvas Jebakumar K
authors.initials: SJK
authors.lastname: Prince
authors.affiliation: School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, CT1 1QU, United Kingdom.
authors.forename: Naeem Hasan
authors.initials: NH
authors.lastname: Syed
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Li
authors.initials: L
authors.lastname: Song
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Babu
authors.initials: B
authors.lastname: Valliyodan
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: National Center for Soybean Biotechnology and Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA. Electronic address: nguyenhenry@missouri.edu.
authors.forename: Henry T
authors.initials: HT
authors.lastname: Nguyen
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D002734:Chlorophyll / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism / Q000648:ultrastructure; D055864:Droughts; D000071837:Fibrillins; D055868:Floods; D005838:Genotype; D005947:Glucose / Q000378:metabolism; D008840:Microfilament Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D010788:Photosynthesis / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D054046:Plant Stomata / Q000502:physiology; D011887:Raffinose / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013025:Glycine max / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013213:Starch / Q000378:metabolism; D013312:Stress, Physiological; D013395:Sucrose / Q000378:metabolism; D014867:Water / Q000378:metabolism
chemical_list: D000071837:Fibrillins; D008840:Microfilament Proteins; D010940:Plant Proteins; D014867:Water; D002734:Chlorophyll; D013395:Sucrose; D000040:Abscisic Acid; D013213:Starch; D005947:Glucose; D011887:Raffinose
keywords: Drought; Flooding; Hormones; Plastoglobules; Slow wilting; Soluble sugars