Expression of a heterologous SnRK1 in tomato increases carbon assimilation, nitrogen uptake and modifies fruit development.
SnRK1 (sucrose non-fermenting-1-related protein kinase 1) plays an important role in plant carbon metabolism and development. To understand the mechanism of carbon and nitrogen metabolism regulated by MhSnRK1 from pingyitiancha (Malus hupehensis Rehd. var. pinyiensis Jiang), two transgenic lines (T2-7 and T2-9) over expressing this gene in tomato were studied. SnRK1 activity in the leaves of 2 transgenic lines was increased by 15-16% compared with that in the wild-type. The leaf photosynthetic rate in transgenic tomatoes was higher than the wild-type. The activity of sucrose synthase breakdown and ADP-glucose pyrophosphorylase was also increased, by approximately 25-36% and 44-48%, respectively, whereas sucrose synthase synthesis and sucrose phosphate synthase activities were unchanged. The content of starch in the leaves and red-ripening fruits was higher than that of the wild-type. The transgenic fruit ripened ∼10 days earlier than the wild-type. The nitrate reductase activity (mgplant⁻¹ h⁻¹) shows no significant difference between the transgenic plant and the wild-type, but the N-uptake efficiency and root/shoot ratio in the T2-9 line were 15% and 35% higher than that in the wild-type, respectively. These results suggest that over expressing MhSnRK1 can increase both the carbon and nitrogen assimilation rate of the plant as well as regulate the development of fruit.
College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, Shandong 271018, PR China.
Xinliang
X
Wang
Futian
F
Peng
Minji
M
Li
Le
L
Yang
Guangjie
G
Li
D002244:Carbon / Q000493:pharmacokinetics*; D005638:Fruit / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D014644:Genetic Variation; D005838:Genotype; D051599:Glucose-1-Phosphate Adenylyltransferase / Q000378:metabolism; D005964:Glucosyltransferases / Q000378:metabolism; D018551:Solanum lycopersicum / Q000235:genetics* / Q000378:metabolism*; D050901:Nitrate Reductase / Q000378:metabolism; D009584:Nitrogen / Q000493:pharmacokinetics*; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D013213:Starch / Q000378:metabolism
D010937:Plant Growth Regulators; D002244:Carbon; D013213:Starch; D050901:Nitrate Reductase; D005964:Glucosyltransferases; C022699:sucrose synthase; C022698:sucrose-phosphate synthase; D011494:Protein Kinases; D051599:Glucose-1-Phosphate Adenylyltransferase; D009584:Nitrogen