Rice Phytochrome B (OsPhyB) Negatively Regulates Dark- and Starvation-Induced Leaf Senescence
AbstractLight regulates leaf senescence and light deprivation causes large-scale transcriptional reprogramming to dismantle cellular components and remobilize nutrients to sink organs, such as seeds and storage tissue. We recently reported that in Arabidopsis (Arabidopsis thaliana), Phytochrome-Interacting Factor4 (PIF4) and PIF5 promote dark-induced senescence and natural senescence by directly activating the expression of typical senescence-associated genes (SAGs), including ORESARA1 (ORE1) and ETHYLENE INSENSITIVE3 (EIN3). In contrast, phytochrome B (PhyB) inhibits leaf senescence by repressing PIF4 and PIF5 at the post-translational level. Although we found how red light signaling represses leaf senescence in Arabidopsis, it remains unknown whether PhyB and/or PhyA are involved in leaf senescence in rice (Oryza sativa). Here we show that rice phyB knockout mutants (osphyB-1, -2, and -3) exhibited an early senescence phenotype during dark-induced senescence, but an osphyA knockout mutant (osphyA-3) senesced normally. The RT-qPCR analysis revealed that several senescence-associated genes, including OsORE1 and OsEIN3, were significantly up-regulated in osphyB-2 mutants, indicating that OsPhyB also inhibits leaf senescence, like Arabidopsis PhyB. We also found that leaf segments of osphyB-2 senesced faster even under light conditions. Supplementation with nitrogen compounds, such as KNO3 and NH4NO3, rescued the early senescence phenotype of osphyB-2, indicating that starvation is one of the major signaling factors in the OsPhyB-dependent leaf senescence pathway. View Full-Text
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Piao, W.; Kim, E.-Y.; Han, S.-H.; Sakuraba, Y.; Paek, N.-C. Rice Phytochrome B (OsPhyB) Negatively Regulates Dark- and Starvation-Induced Leaf Senescence. Plants 2015, 4, 644-663.
Piao W, Kim E-Y, Han S-H, Sakuraba Y, Paek N-C. Rice Phytochrome B (OsPhyB) Negatively Regulates Dark- and Starvation-Induced Leaf Senescence. Plants. 2015; 4(3):644-663.Chicago/Turabian Style
Piao, Weilan; Kim, Eun-Young; Han, Su-Hyun; Sakuraba, Yasuhito; Paek, Nam-Chon. 2015. "Rice Phytochrome B (OsPhyB) Negatively Regulates Dark- and Starvation-Induced Leaf Senescence." Plants 4, no. 3: 644-663.