Role of the <i>Arabidopsis</i> Glucose Sensor HXK1 in Nutrient, Light, and Hormonal Signaling

TLDR

Glucose modulates many vital processes in photosynthetic plants. The study analyzes Arabidopsis gin2 mutants to define the physiological functions of hexokinase HXK1 in the plant glucose‑signaling network. Plants employ HXK as a glucose sensor to integrate nutrient, light, and hormone signaling for growth and development control. HXK1 links intrinsic signals to external light intensity, and gin2 mutants lacking catalytic activity still maintain diverse signaling functions—gene expression, cell proliferation, root and inflorescence growth, leaf expansion, and senescence—demonstrating that glucose signaling can be uncoupled from metabolism, while the mutants are auxin‑insensitive and cytokinin‑hypersensitive.

Abstract

Glucose modulates many vital processes in photosynthetic plants. Analyses of Arabidopsis glucose insensitive2 (gin2) mutants define the physiological functions of a specific hexokinase (HXK1) in the plant glucose-signaling network. HXK1 coordinates intrinsic signals with extrinsic light intensity. HXK1 mutants lacking catalytic activity still support various signaling functions in gene expression, cell proliferation, root and inflorescence growth, and leaf expansion and senescence, thus demonstrating the uncoupling of glucose signaling from glucose metabolism. The gin2 mutants are also insensitive to auxin and hypersensitive to cytokinin. Plants use HXK as a glucose sensor to interrelate nutrient, light, and hormone signaling networks for controlling growth and development in response to the changing environment.