GROWTH REGULATING FACTOR5 Stimulates Arabidopsis Chloroplast Division, Photosynthesis, and Leaf Longevity  . Issue 3 (20th January 2015)

• Record Type: Journal Article
• Authors: Vercruyssen, Liesbeth; Tognetti, Vanesa B.; Gonzalez, Nathalie; Van Dingenen, Judith; De Milde, Liesbeth; Bielach, Agnieszka; De Rycke, Riet; Van Breusegem, Frank; Inzé, Dirk
• Is Part Of: Plant physiology. Volume 167:Issue 3(2015)
• Page Start: 817
• Page End: 832
• Publication Date: 2015-01-20
• Subjects: Plant physiology -- Periodicals; Botany -- Periodicals; Periodicals; Electronic journals; 571.2
• DOI: 10.1104/pp.114.256180
• Languages: English
• ISSNs: 0032-0889

Abstract

Abstract : A transcription factor increases plant productivity by delaying leaf senescence and stimulating leaf cell division, chloroplast division, photosynthesis, and tolerance to nitrogen deprivation. Abstract: Arabidopsis ( Arabidopsis thaliana ) leaf development relies on subsequent phases of cell proliferation and cell expansion. During the proliferation phase, chloroplasts need to divide extensively, and during the transition from cell proliferation to expansion, they differentiate into photosynthetically active chloroplasts, providing the plant with energy. The transcription factor GROWTH REGULATING FACTOR5 (GRF5) promotes the duration of the cell proliferation period during leaf development. Here, it is shown that GRF5 also stimulates chloroplast division, resulting in a higher chloroplast number per cell with a concomitant increase in chlorophyll levels in 35S : GRF5 leaves, which can sustain higher rates of photosynthesis. Moreover, 35S : GRF5 plants show delayed leaf senescence and are more tolerant for growth on nitrogen-depleted medium. Cytokinins also stimulate leaf growth in part by extending the cell proliferation phase, simultaneously delaying the onset of the cell expansion phase. In addition, cytokinins are known to be involved in chloroplast development, nitrogen signaling, and senescence. Evidence is provided that GRF5 and cytokinins synergistically enhance cell division and chlorophyll retention after dark-induced senescence, which suggests that they also cooperate to stimulate chloroplast division and nitrogen assimilation. Taken together with the increased leaf size, ectopic expression of GRF5 has great potential to improve plant productivity.