title: Proteome Analysis Reveals Extensive Light Stress-Response Reprogramming in the SeagrassZostera muelleri(Alismatales, Zosteraceae) Metabolism.
abstract: Seagrasses are marine ecosystem engineers that are currently declining in abundance at an alarming rate due to both natural and anthropogenic disturbances in ecological niches. Despite reports on the morphological and physiological adaptations of seagrasses to extreme environments, little is known of the molecular mechanisms underlying photo-acclimation, and/or tolerance in these marine plants. This study applies the two-dimensional isoelectric focusing (2D-IEF) proteomics approach to identify photo-acclimation/tolerance proteins in the marine seagrassZostera muelleri. For this,Z. muelleriwas exposed for 10 days in laboratory mesocosms to saturating (control, 200 μmol photons m-2s-1), super-saturating (SSL, 600 μmol photons m-2s-1), and limited light (LL, 20 μmol photons m-2s-1) irradiance conditions. Using LC-MS/MS analysis, 93 and 40 protein spots were differentially regulated under SSL and LL conditions, respectively, when compared to the control. In contrast to the LL condition,Z. muellerirobustly tolerated super-saturation light than control conditions, evidenced by their higher relative maximum electron transport rate and minimum saturating irradiance values. Proteomic analyses revealed up-regulation and/or appearances of proteins belonging to the Calvin-Benson and Krebs cycle, glycolysis, the glycine cleavage system of photorespiration, and the antioxidant system. These proteins, together with those from the inter-connected glutamate-proline-GABA pathway, shapedZ. muelleriphotosynthesis and growth under SSL conditions. In contrast, the LL condition negatively impacted the metabolic activities ofZ. muelleriby down-regulating key metabolic enzymes for photosynthesis and the metabolism of carbohydrates and amino acids, which is consistent with the observation with lower photosynthetic performance under LL condition. This study provides novel insights into the underlying molecular photo-acclimation mechanisms inZ. muelleri, in addition to identifying protein-based biomarkers that could be used as early indicators to detect acute/chronic light stress in seagrasses to monitor seagrass health.
authors.affiliation: Climate Change Cluster, Faculty of Science, University of Technology Sydney (UTS) Sydney, NSW, Australia.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kumar
authors.affiliation: School of Life Sciences and Proteomics Core Facility, Faculty of Science, University of Technology Sydney (UTS) Sydney, NSW, Australia.
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Padula
authors.affiliation: Climate Change Cluster, Faculty of Science, University of Technology Sydney (UTS) Sydney, NSW, Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Davey
authors.affiliation: Climate Change Cluster, Faculty of Science, University of Technology Sydney (UTS) Sydney, NSW, Australia.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Pernice
authors.affiliation: Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences (CAS) Guangzhou, China.
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: Climate Change Cluster, Faculty of Science, University of Technology Sydney (UTS) Sydney, NSW, Australia.
authors.forename: Gaurav
authors.initials: G
authors.lastname: Sablok
authors.affiliation: Departamento de Ecología y Biodiversidad, Facultad de Ecología y Recursos Naturales, Universidad Andres BelloSantiago, Chile; Center of Applied Ecology and Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de ChileSantiago, Chile.
authors.forename: Loretto
authors.initials: L
authors.lastname: Contreras-Porcia
authors.affiliation: Climate Change Cluster, Faculty of Science, University of Technology Sydney (UTS) Sydney, NSW, Australia.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Ralph
keywords: 2D-IEF; Zostera muelleri; light stress; proteome profiling; seagrass