PSARK::IPT expression causes protection of photosynthesis in tobacco plants during N deficiency

• Published in: Environmental and experimental botany Vol. 98; pp. 40 - 46
• Main Authors: Rubio-Wilhelmi, Maria del Mar, Reguera, Maria, Sanchez-Rodriguez, Eva, Romero, Luis, Blumwald, Eduardo, Ruiz, Juan Manuel
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.02.2014; Elsevier
• Subjects: Biological and medical sciences; Cytokinins; Fundamental and applied biological sciences. Psychology; Nicotianatabaccum; Nitrogen deficiency; Photosynthetic rates; Sugar metabolism; Tobacco plants; Cytokinins; Nitrogen deficiency; Photosynthetic rates; Sugar metabolism; Nicotianatabaccum; Tobacco plants; Nicotiana; Deficiency; Plant ecology; Nitrogen; Metabolism; Cytokinin; Dicotyledones; Angiospermae; Botany; Plant growth substance; Spermatophyta; Solanaceae; Photosynthesis; Sugar
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2013.10.011

•N-deficiency affects primary photosynthesis and sugar metabolism.•Transgenic plants expressing IPT gene coding the rate-limiting step in CKs synthesis.•WT plants under N-limited, reduced biomass and photosynthetic parameters.•Transgenic plants under N-limited, maintained biomass and photosynthetic parameters.•Expression of PSARK::IPT in tobacco improves the strength of the sink under N-limited. Wild type (WT) and transgenic tobacco plants expressing isopentenyltransferase (IPT), a gene coding the rate-limiting step in cytokinins (CKs) synthesis, were grown under limited nitrogen (N) conditions. WT tobacco plants under N deficit showed a drastic reduction in photosynthetic rate (A) and the maximum carboxylation rate of Rubisco (Vcmax), the maximum rate of the electron transport (Jmax) and the use of triose-P (TPU) parameters. However, the expression an IPT gene driven by PSARK, a stress-and maturation-induced promoter, in tobacco plants under N deficiency leads the maintenance of photosynthesis and leaf biomass related with the maintenance of sm-Rubisco transcripts levels. Limited increase in sugar concentration as well as the maintenance of leaf biomass observed in transgenic plants would indicate CKs may play a role in the sink limitation caused by deficiency of N, enhancing the strength of the sink, such as young leaves, and enhancing foliar biomass under severe N deficiency.