Leaf Senescence Regulation Mechanism Based on Comparative Transcriptome Analysis in Foxtail Millet

Abstract

Leaf senescence, a pivotal process in plants, directly influences both crop yield and nutritional quality. Foxtail millet (Setaria italica) is a C4 model crop renowned for its exceptional nutritional value and stress tolerance characteristics. However, there is a lack of research on the identification of senescence-associated genes (SAGs) and the underlying molecular regulatory mechanisms governing this process. In this study, a dark-induced senescence (DIS) experimental system was applied to investigate the extensive physiological and transcriptomic changes in two foxtail millet varieties with different degrees of leaf senescence. The physiological and biochemical indices revealed that the light senescence (LS) variety exhibited a delayed senescence phenotype, whereas the severe senescence (SS) variety exhibited an accelerated senescence phenotype. The most evident differences in gene expression profiles between these two varieties during DIS included photosynthesis, chlorophyll, and lipid metabolism. Comparative transcriptome analysis further revealed a significant up-regulation of genes related to polysaccharide and calcium ion binding, nitrogen utilization, defense response, and malate metabolism in LS. In contrast, the expression of genes associated with redox homeostasis, carbohydrate metabolism, lipid homeostasis, and hormone signaling was significantly altered in SS. Through WGCNA and RT-qPCR analyses, we identified three SAGs that exhibit potential negative regulation towards dark-induced leaf senescence in foxtail millet. This study establishes the foundation for a further comprehensive examination of the regulatory network governing leaf senescence and provides potential genetic resources for manipulating senescence in foxtail millet.

Advances in Molecular Plant Sciences

“…and accelerated senescence, laying the groundwork for future research on leaf senescence regulation and potential genetic improvements [9]. In Arabidopsis, Wang et al utilized the CRISPR/dCas9-TET1cd system that targeted epigenetic editing, altering the methylation status of a spontaneously occurring epiallele, demonstrating that reducing methylation levels in specific gene promoter regions can enhance gene expression, thereby influencing leaf senescence in plants [10].…”

“…Through investigating the Leaf senescence 1 (LS1) gene in rice, Zhang et al uncovered the role of C2H2 zinc-finger protein in regulating leaf senescence through the modulation of reactive oxygen species (ROS) production, shedding light on the molecular mechanisms underlying premature senescence and its impact on plant health [ 8 ]. In parallel, the research of Zhen et al on foxtail millet identified key senescence-associated genes and regulatory mechanisms through a dark-induced senescence system, revealing significant physiological and transcriptomic differences between varieties with delayed and accelerated senescence, laying the groundwork for future research on leaf senescence regulation and potential genetic improvements [ 9 ]. In Arabidopsis, Wang et al utilized the CRISPR/dCas9-TET1cd system that targeted epigenetic editing, altering the methylation status of a spontaneously occurring epiallele, demonstrating that reducing methylation levels in specific gene promoter regions can enhance gene expression, thereby influencing leaf senescence in plants [ 10 ].…”