Senescence-induced NAC(senNAC)TFs play a crucial role in senescence during the final stage of leaf development.In this study,we identified a rice senNAC,ONAC016,which functions as a positive regulator of leaf senescen...Senescence-induced NAC(senNAC)TFs play a crucial role in senescence during the final stage of leaf development.In this study,we identified a rice senNAC,ONAC016,which functions as a positive regulator of leaf senescence.The expression of ONAC016 increased rapidly in rice leaves during the progression of dark-induced and natural senescence.The onac016-1 knockout mutant showed a delayed leaf yellowing phenotype,whereas the overexpression of ONAC016 accelerated leaf senescence.Notably,ONAC016 expression was upregulated by abscisic acid(ABA),and thus detached leaves of the onac016-1 mutant remained green much longer under ABA treatment.Quantitative RT-PCR analysis showed that ONAC016 upregulates the genes associated with chlorophyll degradation,senescence,and ABA signaling.Yeast one-hybrid and dual-luciferase assays revealed that ONAC016 binds directly to the promoter regions of OsNAP,a key gene involved in chlorophyll degradation and ABA-induced senescence.Taken together,these results suggest that ONAC016 plays an important role in promoting leaf senescence through the ABA signaling pathway involving OsNAP.展开更多
Chimeric plants composed of green and albino tissues have great ornamental value.To unveil the functional genes responsible for albino phenotypes in chimeric plants,we inspected the complete plastid genomes(plastomes)...Chimeric plants composed of green and albino tissues have great ornamental value.To unveil the functional genes responsible for albino phenotypes in chimeric plants,we inspected the complete plastid genomes(plastomes)in green and albino leaf tissues from 23 ornamental chimeric plants belonging to 20 species,including monocots,dicots,and gymnosperms.In nine chimeric plants,plastomes were identical between green and albino tissues.Meanwhile,another 14 chimeric plants were heteroplasmic,showing a mutation between green and albino tissues.We identified 14 different point mutations in eight functional plastid genes related to plastid-encoded RNA polymerase(rpo)or photosystems which caused albinism in the chimeric plants.Among them,12 were deleterious mutations in the target genes,in which early termination appeared due to small deletion-mediated frameshift or single nucleotide substitution.Another was single nucleotide substitution in an intron of the ycf3 and the other was a missense mutation in coding region of the rpoC2 gene.We inspected chlorophyll structure,protein functional model of the rpoC2,and expression levels of the related genes in green and albino tissues of Reynoutria japonica.A single amino acid change,histidine-to-proline substitution,in the rpoC2 protein may destabilize the peripheral helix of plastid-encoded RNA polymerase,impairing the biosynthesis of the photosynthesis system in the albino tissue of R.japonica chimera plant.展开更多
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(2022R1A2C1091553 to Nam-Chon Paek and 2022R1F1A1075022 to Kiyoon Kang)。
文摘Senescence-induced NAC(senNAC)TFs play a crucial role in senescence during the final stage of leaf development.In this study,we identified a rice senNAC,ONAC016,which functions as a positive regulator of leaf senescence.The expression of ONAC016 increased rapidly in rice leaves during the progression of dark-induced and natural senescence.The onac016-1 knockout mutant showed a delayed leaf yellowing phenotype,whereas the overexpression of ONAC016 accelerated leaf senescence.Notably,ONAC016 expression was upregulated by abscisic acid(ABA),and thus detached leaves of the onac016-1 mutant remained green much longer under ABA treatment.Quantitative RT-PCR analysis showed that ONAC016 upregulates the genes associated with chlorophyll degradation,senescence,and ABA signaling.Yeast one-hybrid and dual-luciferase assays revealed that ONAC016 binds directly to the promoter regions of OsNAP,a key gene involved in chlorophyll degradation and ABA-induced senescence.Taken together,these results suggest that ONAC016 plays an important role in promoting leaf senescence through the ABA signaling pathway involving OsNAP.
基金This work was supported by the Bio&Medical Technology Development Program of the NRF,MSIP,Republic of Korea(grant no.NRF-2015M3A9A5030733)grants from the Nuclear R&D Program of the Ministry of Science and ICT(MSIT)and the research program of KAERI,Republic of Korea.
文摘Chimeric plants composed of green and albino tissues have great ornamental value.To unveil the functional genes responsible for albino phenotypes in chimeric plants,we inspected the complete plastid genomes(plastomes)in green and albino leaf tissues from 23 ornamental chimeric plants belonging to 20 species,including monocots,dicots,and gymnosperms.In nine chimeric plants,plastomes were identical between green and albino tissues.Meanwhile,another 14 chimeric plants were heteroplasmic,showing a mutation between green and albino tissues.We identified 14 different point mutations in eight functional plastid genes related to plastid-encoded RNA polymerase(rpo)or photosystems which caused albinism in the chimeric plants.Among them,12 were deleterious mutations in the target genes,in which early termination appeared due to small deletion-mediated frameshift or single nucleotide substitution.Another was single nucleotide substitution in an intron of the ycf3 and the other was a missense mutation in coding region of the rpoC2 gene.We inspected chlorophyll structure,protein functional model of the rpoC2,and expression levels of the related genes in green and albino tissues of Reynoutria japonica.A single amino acid change,histidine-to-proline substitution,in the rpoC2 protein may destabilize the peripheral helix of plastid-encoded RNA polymerase,impairing the biosynthesis of the photosynthesis system in the albino tissue of R.japonica chimera plant.
