Pectin methylesterase is required for guard cell function in response to heat.

Pectin is an important cell wall polysaccharide required for cellular adhesion, extension, and plant growth. The pectic methylesterification status of guard cell walls influences the movement of stomata in response to different stimuli. Pectin methylesterase (PME) has a profound effect on cell wall modification, especially on the degree of pectic methylesterification during heat response. The Arabidopsis thaliana PME34 gene is highly expressed in guard cells and in response to the phytohormone abscisic acid. The genetic data highlighted the significant role of PME34 in heat tolerance through the regulation of stomatal movement. Thus, the opening and closure of stomata is mediated by changes in response to a given stimulus, could require a specific cell wall modifying enzyme to function properly.