Nitrogen (N) efficiency of winter oilseed rape (Brassica napus L.) line-cultivars (cvs.), defined as high grain yield under N limitation, has been primarily attributed to maintained N uptake during reproductive growth (N uptake efficiency) in combination with delayed senescence of the older leaves accompanied with maintained photosynthetic capacity (functional stay-green). However, it is not clear whether genotypic variation in N starvation-induced leaf senescence is due to leaf-inherent factors and/or governed by root-mediated signals. Therefore, the N-efficient and stay-green cvs. NPZ-1 and Apex were reciprocally grafted with the N-inefficient and early-senescing cvs. NPZ-2 and Capitol, respectively and grown in hydroponics. The senescence status of older leaves after 12 days of N starvation assessed by SPAD, photosynthesis and the expression of the senescence-specific cysteine protease gene SAG12-1 revealed that the stay-green phenotype of the cvs. NPZ-1 and Apex under N starvation was primarily under the control of leaf-inherent factors. The same four cultivars were submitted to N starvation for up to 12 days in a time-course experiment. The specific leaf contents of biologically active and inactive cytokinins (CKs) and the expression of genes involved in CK homeostasis revealed that under N starvation leaves of early-senescing cultivars were characterized by inactivation of biologically active CKs, whereas in stay-green cultivars synthesis, activation, binding of and response to biologically active CKs were favoured. These results suggest that the homeostasis of biologically active CKs was the predominant leaf-inherent factor for cultivar differences in N starvation-induced leaf senescence and thus N efficiency.

Department of Plant and Environmental Sciences Copenhagen Plant Science Center University of Copenhagen Højbakkegård Allé13 DK 2630 Taastrup Denmark

Department of Plant and Environmental Sciences Copenhagen Plant Science Center University of Copenhagen Højbakkegård Allé13 DK 2630 Taastrup Denmark Global Change Research Centre CzechGlobe AS CR v v i Drásov 470 Cz 664 24 Drásov Czech Republic

Institute of Plant Nutrition Leibniz University of Hannover Herrenhäuser Str 2 D 30419 Hannover Germany

Zobrazit více v PubMed

Albacete Moreno A, Cantero AE, Grosskinsky D, et al. 2014. Ectopic overexpression of the cell wall invertase gene CIN1 increases water use efficiency in tomato (Solanum lycopersicum L.) and confers extreme drought tolerance. Journal of Experimental Botany 66, 863–878. PubMed

Arvidsson S, Kwasniewski M, Diego M, Riaño-Pachón DM, Mueller-Roeber B. 2008. QuantPrime—a flexible tool for reliable high-throughput primer design for quantitative PCR. BMC Bioinformatics doi: 10.1186/1471-2105-9-465. PubMed PMC

Balazadeh S, Riaño-Pachón DM, Mueller-Roeber B. 2008. Transcription factors regulating leaf senescence in Arabidopsis thaliana . Plant Biology 10, 63–75. PubMed

Balibrea Lara ME, Gonzalez MCG, Fatima T, Ehneß T, Lee TK, Roels R, Tanner W, Roitsch T. 2004. Extracellular invertase is an essential component of cytokinin mediated delay of senescence. Plant Cell 16, 1276–1287. PubMed PMC

Berry PM, Spink J, Foulkes MJ, White PJ. 2010. The physiological basis of genotypic differences in nitrogen use efficiency in oilseed rape (Brassica napus L.). Field Crops Research 119, 365–373.

Buchanan-Wollaston V. 1997. The molecular biology of leaf senescence. Journal of Experimental Botany 48, 181–199.

Dai J, Dong H. 2011. Stem girdling influences concentration of endogenous cytokinins and abscisic acid in relation to leaf senescence in cotton. Acta Physiologiae Plantarum 33, 1697–1705.

del Mar Rubio-Wilhelmi M, Reguera M, Sanchez-Rodriguez E, Romero L, Blumwald E, Ruiz JM. 2014. PSARK::IPT expression causes protection of photosynthesis in tobacco plants during N deficiency. Environmental and Experimental Botany 98, 40–46.

Desclos M, Dubousset L, Etienne P, Le Caherec F, Satoh H, Bonnefoy J, Ourry A, Avice JC. 2008. A proteomic approach to reveal a novel role of Brassica napus drought 22 kD/water-soluble chlorophyll-binding protein in young leaves during nitrogen remobilization induced by stressful conditions. Plant Physiology 147, 1830–1844. PubMed PMC

Dong H, Niu Y, Li W, Zhang D. 2008. Effects of cotton rootstock on endogenous cytokinins and abscisic acid in xylem sap and leaves in relation to leaf senescence. Journal of Experimental Botany 59, 1295–1304. PubMed

Etienne P, Desclos M, Gou LL, Gombert J, Bonnefoy J, Maurel K, Le Dily F, Ourry A, Avice JC. 2007. N-protein mobilisation associated with the leaf senescence process in oilseed rape is concomitant with the disappearance of trypsin inhibitor activity. Functional Plant Biology 34, 895–906. PubMed

Evans JR. 1989. Photosynthesis and nitrogen relationships in leaves of C3 plants. Oecologia 78, 9–19. PubMed

Gajdošová S, Spíchal L, Kamínek M. 2011. Distribution, biological activities, metabolism, and the conceivable function of cis-zeatin-type cytokinins in plants. Journal of Experimental Botany 62, 2827–2840. PubMed

Galuszka P, Popelková H, Werner T, Frébortová J, Pospísilová H, Mik V, Köllmer I, Schmülling T, Frébort I. 2007. Biochemical characterization of cytokinins oxidases/dehydrogenases from Arabidopsis thaliana expressed in Nicotiana tabacum L. Journal of Plant Growth Regulation 26, 255–267.

Gan S, Amasino RM. 1995. Inhibition of leaf senescence by autoregulated production of cytokinins. Science 270, 1986–1988. PubMed

Grbić V. 2003. SAG2 and SAG12 protein expression in senescing Arabidopsis plants. Physiologia Plantarum 119, 263–269.

Gregersen PL, Culetic A, Boschian L, Krupinska K. 2013. Plant senescence and crop productivity. Plant Molecular Biology 82, 603–622. PubMed

Großkinsky DK, Albacete A, Jammer A, Krbez P, van der Graaff E, Pfeifhofer H, Roitsch T. 2014. A rapid phytohormone and phytoalexin screening method for physiological phenotyping. Molecular Plant 7, 1053–1056. PubMed

He P, Osaki M, Takebe M, Shinano T, Wasaki J. 2005. Endogenous hormones and expression of senescence-related genes in different senescent types of maize. Journal of Experimental Botany 56, 1117–1128 PubMed

Hou B, Lim EK, Higgins GS, Bowles DJ. 2004. N-glucosylation of cytokinins by glycosyltransferases of Arabidopsis thaliana . Journal of Biological Chemistry 279, 47822–47832. PubMed

Jin SH, Ma XM, Kojima M, Sakakibara H, Wang YW, Hou BK. 2013. Overexpression of glucosyltransferase UGT85A1 influences trans-Zeatin homeostasis and trans-zeatin responses likely through O-glucosylation. Planta 237, 991–999. PubMed

Kamh M, Wiesler F, Ulas A, Horst WJ. 2005. Root growth and N-uptake of oilseed rape (Brassica napus L.) cultivars differing in nitrogen efficiency. Journal of Plant Nutrition and Soil Science 168, 130–137.

Kim HJ, Hojin R, Hong SH, Woo HR, Lim PO, Lee IC, Sheen J, Nam HG, Hwang I. 2006. Cytokinin-mediated control of leaf longevity by AHK3 through phosphorylation of ARR2 in Arabidopsis . Proceedings of the National Academy of Sciences of the United States of America 103, 814–819. PubMed PMC

Koeslin-Findeklee F, Meyer A, Girke A, Beckmann K, Horst WJ. 2014. The superior nitrogen efficiency of winter oilseed rape (Brassica napus L.) hybrids is not related to delayed nitrogen starvation-induced leaf senescence. Plant and Soil 384, 347–362.

Koeslin-Findeklee F, Safavi Rizi V, Becker MA, Parra-Londono S, Arif M, Balazadeh S, Mueller-Roeber M, Kunze R, Horst WJ. 2015. Transcriptomic analysis of nitrogen starvation- and cultivar-specific leaf senescence in winter oilseed rape (Brassica napus L.). Plant Science 233, 174–185. PubMed

Kowalska M, Galuszka P, Frébortová J, Ŝebela M, Béres T, Hluska T, Ŝmehilová M, Bilyeu KD, Frébort I. 2010. Vacuolar and cytosolic cytokinin dehydrogenases of Arabidopsis thaliana . Phytochemistry 71, 1970–1978. PubMed

Köllmer I, Novák O, Strnad M, Schmülling T, Werner T. 2014. Overexpression of the cytosolic cytokinin oxidase/dehydrogenase (CKX7) from Arabidopsis causes specific changes in root growth and xylem differentiation. Plant Journal 78, 359–371. PubMed

Kuroha T, Tokungaga H, Kojima M, Ueda N, Ishida T, Nagawa S, Fukuda H, Sugimoto K, Sakakibara H. 2009. Functional analyses of LONELY GUY cytokinin-activating enzymes reveal the importance of the direct activation pathway in Arabidopsis . Plant Cell 21, 3152–3169. PubMed PMC

Kusaba M, Tanaka A, Tanaka R. 2013. Stay-green plants: what do they tell us about the molecular mechanism of leaf senescence. Photosynthesis Research 117, 221–234. PubMed

Lim PO, Kim HJ, Nam HG. 2007. Leaf senescence. Annual Review of Plant Biology 58, 115–136. PubMed

Livak KJ, Schmittgen TD. 2001. Analysis of relative gene expression data using real-time quantitative PCR and the 2-ΔΔCT method. Methods 25, 402–408. PubMed

Miyawaki K, Matsumoto-Kitano M, Kakimoto T. 2004. Expression of cytokinin biosynthetic isopentenyltransferaes genes in Arabidopsis: tissue specificity and regulation by auxin, cytokinin, and nitrate. Plant Journal 37, 128–138. PubMed

Moroni JS. 1997. Studies on the efficiency of rapeseed (Brassica napus L.) germplasm for the acquisition and the utilization of inorganic nitrogen. PhD thesis, University of Alberta, Canada.

Parlitz S, Kunze R, Mueller-Roeber B, Balazadeh S. 2011. Regulation of photosynthesis and transcription factor expression by leaf shading and re-illumination in Arabidopsis leaves. Journal of Plant Physiology 168, 1311–1319. PubMed

Rauf M, Arif M, Dortay H, Matallana-Ramírez LP, Waters MT, Nam HG, Lim PO, Mueller-Roeber B, Balazadeh S. 2013. ORE1 balances leaf senescence against maintenance by antagonizing G2-like-mediated transcription. EMBO Reports 14, 382–388. PubMed PMC

Sakakibara H. 2006. Cytokinins: activity, biosynthesis, and translocation. Annual Review of Plant Biology 57, 431–449. PubMed

Sakuraba Y, Balazadeh S, Tanaka R, Mueller-Roeber B, Tanaka A. 2012a. Overproduction of chl B retards senescence through transcriptional reprogramming in Arabidopsis . Plant Cell Physiology 53, 505–517. PubMed

Sakuraba Y, Schelbert S, Park SY, Han SH, Lee BD, Andrès CB, Kessler F, Hörtensteiner S, Paeck NC. 2012b. Stay-green and chlorophyll catabolic enzymes interact at light-harvesting complex II for chlorophyll detoxification during leaf senescence in Arabidopsis . Plant Cell 24, 507–518. PubMed PMC

Schmitz RY, Skoog F, Playtis AJ, Leonard NJ. 1972. Cytokinins: synthesis and biological activity of geometric and position isomers of zeatin. Plant Physiology 50, 702–705. PubMed PMC

Schmülling T, Werner T, Riefler M, Krupková E, Bartina y Manns B. 2003. Structure and function of cytokinin oxidase/dehydrogenase genes of maize, rice, Arabidopsis and other species. Journal of Plant Research 116, 241–252. PubMed

Schmülling T. 2004. Cytokinin. In: Lennarz W and Lane MD, eds. Encyclopedia of Biological Chemistry. Academic Press/Elsevier Science.

Schulte auf’m Erley G, Wijaya KA, Ulas A, Becker H, Wiesler F, Horst WJ. 2007. Leaf senescence and N uptake parameters as selection traits for nitrogen efficiency of oilseed rape cultivars. Physiologia Plantarum 130, 519–531.

Schulte auf’m Erley G, Ambebe TF, Worku M, Bänzinger M, Horst WJ. 2010. Photosynthesis and leaf-nitrogen dynamics during leaf senescence of tropical maize cultivars in hydroponics in relation to N efficiency in the field. Plant and Soil 330, 313–328.

Schulte auf’m Erley G, Behrens T, Ulas A, Wiesler F, Horst WJ. 2011. Agronomic traits contributing to nitrogen efficiency of winter oilseed rape cultivars. Field Crops Research 124, 114–123.

Smart CM. 1994. Gene expression during leaf senescence. New Phytologist 126, 419–448. PubMed

Steibel JP, Poletto R, Coussens PM, Rosa GJM. 2009. A powerful and flexible linear mixed model framework for the analysis of relative quantification RT-PCR data. Genomics 94, 146–152. PubMed

Thomas H, Howarth CJ. 2000. Five ways to stay green. Journal of Experimental Botany 51, 329–337. PubMed

Thomas H, Ougham H. 2014. The stay-green trait. Journal of Experimental Botany 65, 3889–3900. PubMed

Tokunaga H, Kojima M, Kuroha T, Ishida T, Sugimoto K, Kiba T, Sakakibara H. 2012. Arabidopsis lonely guy (LOG) multiple mutants reveal a central role of the LOG-dependent pathway in cytokinin activation. Plant Journal 69, 355–365. PubMed

Trifunović M, Cingel A, Simonović A, Jevremović S, Petrić M, Dragićević IC, Motyka V, Bobrev PI, Zahajská L, Subotić A. 2013. Overexpression of Arabidopsis cytokinin oxidase/dehydrogenase genes AtCKX1 and AtCKX2 in transgenic Centaurium erythraea Rafn. Plant Cell, Tissue and Organ Culture 115, 139–150.

Wang A, Li Y, Zhang C. 2012. QTL mapping for stay-green in maize (Zea mays). Canadian Journal of Plant Science 92, 249–256.

Wang J, Ma XM, Kojima M, Sakakibara H, Hou BK. 2013. Glucosyltransgerase UGT76C1 finely modulates cytokinin responses via cytokinin N-glucosylation in Arabidopsis thaliana . Plant Physiology and Biochemistry 65, 9–16. PubMed

Wingler A, Roitsch T. 2008. Metabolic regulation of leaf senescence: interactions of sugar signalling with biotic and abiotic stress responses. Plant Biology 10, 50–62. PubMed

Zwack PJ, Rashotte AM. 2013. Cytokinin inhibition on leaf senescence. Plant Signal and Behavior 8, e24737; http://dx.doi.org/10.4161/psb.24737 PubMed PMC

Cytokinins and auxins in organs of aquatic carnivorous plants: what do they reflect?