title: Effect of exogenously applied molybdenum on its absorption and nitrate metabolism in strawberry seedlings.
abstract: Molybdenum (Mo)-an essential element of plants-is involved in nitrogen (N) metabolism. Plants tend to accumulate more nitrate and show lower nitrogen use efficiency (NUE) under Mo-deficient conditions. Improving NUE in fruits reduces the negative effect of large applications of chemical fertilizer, but the mechanisms underlying how Mo enhances NUE remain unclear. We cultivated strawberry seedlings sprayed with 0, 67.5, 135, 168.75, or 202.5 g Mo·ha-1in a non-soil culture system. The Mo concentration in every plant tissue analyzed increased gradually as Mo application level rose. Mo application affected iron, copper, and selenium adsorption in roots. Seedlings sprayed with 135 g Mo·ha-1had a higher [15N] shoot:root (S:R) ratio, and15NUE, and produced higher molybdate transporter type 1 (MOT1) expression levels in the roots and leaves. Seedlings sprayed with 135 g Mo·ha-1also had relatively high nitrogen metabolic enzyme activities and up-regulated transcript levels of nitrate uptake genes (NRT1.1; NRT2.1) and nitrate-responsive genes. Furthermore, there was a significantly lower NO3-concentration in the leaves and roots, a higher NH4+concentration in leaves, and a higher glutamine/glutamate (Gln/Glu) concentration at 135 g Mo·ha-1. Seedlings sprayed with 202.5 g Mo·ha-1showed the opposite trend. Taken together, these results suggest that a 135 g Mo·ha-1application was optimal because it enhanced NO3-transport from the roots to the shoots and increased NUE by mediating nitrogen metabolic enzyme activities, nitrate transport, and nitrate assimilation gene activities.
authors.affiliation: State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China.
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.affiliation: State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China.
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Li
authors.affiliation: State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China.
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China. Electronic address: chunying196217@163.com.
authors.forename: Cui-Ying
authors.initials: CY
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Crop Biology, College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China. Electronic address: xilingfu@sdau.edu.cn.
authors.forename: Xi-Ling
authors.initials: XL
authors.lastname: Fu
mesh_terms: D003300:Copper / Q000378:metabolism; D031985:Fragaria / Q000187:drug effects* / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D008982:Molybdenum / Q000633:toxicity*; D009566:Nitrates / Q000378:metabolism*; D009587:Nitrogen Isotopes; D036226:Seedlings / Q000187:drug effects* / Q000378:metabolism; D012643:Selenium / Q000378:metabolism
chemical_list: D009566:Nitrates; D009587:Nitrogen Isotopes; D003300:Copper; D008982:Molybdenum; D007501:Iron; D012643:Selenium
keywords: MOT1; Molybdenum; NUE; Nitrate metabolism; Strawberry