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Compartmentation of photosynthesis gene expression in C4 maize depends on time of day
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Orientador(es)
Resumo(s)
Compared with the ancestral C3 state, C4 photosynthesis occurs at higher rates with improved water and nitrogen use efficiencies. In both C3 and C4 plants, rates of photosynthesis increase with light intensity and are maximal around midday. We determined that in the absence of light or temperature fluctuations, photosynthesis in maize (Zea mays) peaks in the middle of the subjective photoperiod. To investigate the molecular processes associated with these temporal changes, we performed RNA sequencing of maize mesophyll and bundle sheath strands over a 24-h time course. Preferential expression of C4 cycle genes in these cell types was strongest between 6 and 10 h after dawn when rates of photosynthesis were highest. For the bundle sheath, DNA motif enrichment and gene coexpression analyses suggested members of the DNA binding with one finger (DOF) and MADS (MINICHROMOSOME MAINTENANCE FACTOR 1/AGAMOUS/DEFICIENS/Serum Response Factor)-domain transcription factor families mediate diurnal fluctuations in C4 gene expression, while trans-activation assays in planta confirmed their ability to activate promoter fragments from bundle sheath expressed genes. The work thus identifies transcriptional regulators and peaks in cell-specific C4 gene expression coincident with maximum rates of photosynthesis in the maize leaf at midday.
Descrição
Funding Information: This work was supported by the European Commission project 3to4 (grant agreement no: 289582), by Fundação para a Ciência e Tecnologia (FCT) through research unit GREEN-it “Bioresources for Sustainability” (UID/Multi/04551/2013, UIDB/04551/2020), by POPH-QREN to A.R.B. (SFRH/BD/ 105739/2014), A.M.G. (SFRH/BD/89743/2012), and N.J.M.S. (IF/01126/2012), by ERACAPS grant C4BREED and BBSRC grants BB/L014130, BBP0031171, and BB/S006370/1, and by European Research Council Grant Revolution RG80867. Publisher Copyright: © The Author(s) 2023. Published by Oxford University Press on behalf of American Society of Plant Biologists.
Palavras-chave
Physiology Genetics Plant Science