Genetic architecture of source-sink-regulated senescence in maize.

Autor:	Kumar R; Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA., Brar MS; Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA., Kunduru B; Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA., Ackerman AJ; Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA., Yang Y; School of Mathematical and Statistical Sciences, Clemson University, Clemson, SC 29634, USA., Luo F; School of Computing, Clemson University, Clemson, SC 29634, USA., Saski CA; Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634, USA., Bridges WC; School of Mathematical and Statistical Sciences, Clemson University, Clemson, SC 29634, USA., de Leon N; Department of Agronomy, University of Wisconsin, Madison, WI 53706, USA., McMahan C; School of Mathematical and Statistical Sciences, Clemson University, Clemson, SC 29634, USA., Kaeppler SM; Department of Agronomy, University of Wisconsin, Madison, WI 53706, USA., Sekhon RS; Department of Genetics and Biochemistry, Clemson University, Clemson, SC 29634, USA.
Jazyk:	angličtina
Zdroj:	Plant physiology [Plant Physiol] 2023 Nov 22; Vol. 193 (4), pp. 2459-2479.
DOI:	10.1093/plphys/kiad460
Abstrakt:	Source and sink interactions play a critical but mechanistically poorly understood role in the regulation of senescence. To disentangle the genetic and molecular mechanisms underlying source-sink-regulated senescence (SSRS), we performed a phenotypic, transcriptomic, and systems genetics analysis of senescence induced by the lack of a strong sink in maize (Zea mays). Comparative analysis of genotypes with contrasting SSRS phenotypes revealed that feedback inhibition of photosynthesis, a surge in reactive oxygen species, and the resulting endoplasmic reticulum (ER) stress were the earliest outcomes of weakened sink demand. Multienvironmental evaluation of a biparental population and a diversity panel identified 12 quantitative trait loci and 24 candidate genes, respectively, underlying SSRS. Combining the natural diversity and coexpression networks analyses identified 7 high-confidence candidate genes involved in proteolysis, photosynthesis, stress response, and protein folding. The role of a cathepsin B like protease 4 (ccp4), a candidate gene supported by systems genetic analysis, was validated by analysis of natural alleles in maize and heterologous analyses in Arabidopsis (Arabidopsis thaliana). Analysis of natural alleles suggested that a 700-bp polymorphic promoter region harboring multiple ABA-responsive elements is responsible for differential transcriptional regulation of ccp4 by ABA and the resulting variation in SSRS phenotype. We propose a model for SSRS wherein feedback inhibition of photosynthesis, ABA signaling, and oxidative stress converge to induce ER stress manifested as programed cell death and senescence. These findings provide a deeper understanding of signals emerging from loss of sink strength and offer opportunities to modify these signals to alter senescence program and enhance crop productivity. Competing Interests: Conflict of interest statement. The authors declare no conflict of interest. (© American Society of Plant Biologists 2023. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)
Databáze:	MEDLINE
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