title: Enhanced photosynthetic capacity and antioxidant potential mediate brassinosteriod-induced phenanthrene stress tolerance in tomato.
abstract: Photosynthesis, the basal manufacturing process in the earth is habitually restricted by airborne micropollutants such as phenanthrene (PHE). Here, we show that 24-epibrassinolide (EBR), a bioactive plant steroid is able to keep higher photosynthetic capacity consistently for a long period under a shoot-imposed PHE stress in tomato. EBR-promoted photosynthetic capacity and efficiency eventually resulted in a 37.5% increase of biomass under PHE stress. As primary response, transcripts of antioxidant genes were remarkably induced by EBR in PHE-treated plants. Activities of antioxidant and detoxification enzymes were also enhanced by EBR. Notably, EBR-induced higher antioxidant potential was associated with reduced levels of H2O2 and O2(-), resulting in a 32.7% decrease of content of malondialdehyde in the end of experiment and relatively healthy chloroplast ultrastructure in EBR + PHE treatment compared with PHE alone. These results indicate that EBR alleviates shoot-imposed PHE phytotoxicity by maintaining a consistently higher photosynthetic capacity and antioxidant potential in tomato.
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Golam Jalal
authors.initials: GJ
authors.lastname: Ahammed
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China; Tea Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310008, PR China.
authors.forename: Xin
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China. Electronic address: xiaojianxia@zju.edu.cn.
authors.forename: Xiao-Jian
authors.initials: XJ
authors.lastname: Xia
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Kai
authors.initials: K
authors.lastname: Shi
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China.
authors.forename: Yan-Hong
authors.initials: YH
authors.lastname: Zhou
authors.affiliation: Department of Horticulture, Zijingang Campus, Zhejiang University, Hangzhou 310058, PR China; Key Laboratory of Horticultural Plants Growth, Development and Quality Improvement, Agricultural Ministry of China, Hangzhou 310058, PR China.
authors.forename: Jing-Quan
authors.initials: JQ
authors.lastname: Yu
mesh_terms: D000397:Air Pollution; D000975:Antioxidants / Q000032:analysis*; D060406:Brassinosteroids / Q000494:pharmacology*; D002736:Chloroplasts; D018551:Solanum lycopersicum / Q000187:drug effects*; D008315:Malondialdehyde; D010616:Phenanthrenes / Q000378:metabolism*; D010788:Photosynthesis / Q000187:drug effects*; D013312:Stress, Physiological / Q000187:drug effects*
chemical_list: D000975:Antioxidants; D060406:Brassinosteroids; D010616:Phenanthrenes; C031181:phenanthrene; D008315:Malondialdehyde
keywords: Airborne pollutant; Antioxidant enzyme; Brassinosteroids; Photosynthesis; Reactive oxygen species