Light Spectral Composition Modifies Polyamine Metabolism in Young Wheat Plants

Abstract

Although light-emitting diode (LED) technology has extended the research on targeted photomorphogenic, physiological, and biochemical responses in plants, there is not enough direct information about how light affects polyamine metabolism. In this study, the effect of three spectral compositions (referred to by their most typical characteristic: blue, red, and the combination of blue and red [pink] lights) on polyamine metabolism was compared to those obtained under white light conditions at the same light intensity. Although light quality induced pronounced differences in plant morphology, pigment contents, and the expression of polyamine metabolism-related genes, endogenous polyamine levels did not differ substantially. When exogenous polyamines were applied, their roborative effect were detected under all light conditions, but these beneficial changes were correlated with an increase in polyamine content and polyamine metabolism-related gene expression only under blue light. The effect of the polyamines on leaf gene expression under red light was the opposite, with a decreasing tendency. Results suggest that light quality may optimize plant growth through the adjustment of polyamine metabolism at the gene expression level. Polyamine treatments induced different strategies in fine-tuning of polyamine metabolism, which were induced for optimal plant growth and development under different spectral compositions.

Influence of a phyA Mutation on Polyamine Metabolism in Arabidopsis Depends on Light Spectral Conditions

“…Partly similar results were found in the present experiment, as SPM induced the synthesis of PUT and activated the expression of AtADC2 and AtSPMS but decreased that of the AtSPDS2. In wheat, it was also demonstrated that the effect of supplementary blue and far-red light was opposite on the PA metabolism-related gene expression in the leaves; in addition, PA treatment could partly reverse these differences [39]. Nevertheless, in the present study, we first demonstrated that the responses of wild-type and phyA mutant plants are partly different and depend on the light spectral conditions.…”

“…PA biosynthesis is controlled by light (light quality and quantity) [38,39], and on the other hand, PAs are able to influence photosynthesis in several ways (reviewed in [24]). PhyA is a unique photoreceptor responsible for the high far-red light irradiance response…”

“…PA biosynthesis is controlled by light (light quality and quantity) [38,39], and on the other hand, PAs are able to influence photosynthesis in several ways (reviewed in [24]). PhyA is a unique photoreceptor responsible for the high far-red light irradiance response of seedlings, and PhyA regulates various light-dependent responses at metabolite and gene expression levels; however, PhyA may regulate genes other than light-responsive ones through the interaction with corresponding transcription factors [23].…”

“…The spectral composition of the three applied light treatments used in the experiments is described in Table 2. The spectral composition was chosen with some modifications based on our previous study, where the effects of supplementary blue and far-red light and their combination was investigated on PA metabolism, and blue light caused a drastic decrease in the gene expression level of PA metabolism-related gene expression, while the far-red light-induced slight increase of them in the leaves of wheat plants [39].…”

“…It has also been demonstrated that the actual PA pool is influenced by light intensity and light composition [37][38][39]. In addition, it was found that far-red and blue lights induced opposite responses in PA metabolism-related gene expression in wheat plants [39]. Pas increasingly accumulated in tomato leaves from the beginning of illumination [40].…”