CARBOHYDRATE-MODULATED GENE EXPRESSION IN PLANTS

TLDR

Plant gene expression is highly responsive to carbohydrate availability, with sugars inducing or repressing diverse genes that regulate photosynthesis, remobilization, export, storage, and utilization, thereby shaping metabolic activity, resource allocation, and plant development. This review surveys carbohydrate‑modulated gene expression from the molecular to whole‑plant scale and evaluates emerging models of carbohydrate sensing and signal transduction. The authors examine proposed mechanisms by which carbohydrate signals are sensed and transduced to regulate target genes, integrating recent molecular and physiological evidence.

Abstract

Plant gene responses to changing carbohydrate status can vary markedly. Some genes are induced, some are repressed, and others are minimally affected. As in microorganisms, sugar-sensitive plant genes are part of an ancient system of cellular adjustment to critical nutrient availability. However, in multicellular plants, sugar-regulated expression also provides a mechanism for control of resource distribution among tissues and organs. Carbohydrate depletion upregulates genes for photosynthesis, remobilization, and export, while decreasing mRNAs for storage and utilization. Abundant sugar levels exert opposite effects through a combination of gene repression and induction. Long-term changes in metabolic activity, resource partitioning, and plant form result. Sensitivity of carbohydrate-responsive gene expression to environmental and developmental signals further enhances its potential to aid acclimation. The review addresses the above from molecular to whole-plant levels and considers emerging models for sensing and transducing carbohydrate signals to responsive genes.