The effect of UV-B on Arabidopsis leaves depends on light conditions after treatment.

Olga Sztatelman,Halina Gabryś,Agnieszka Katarzyna Banaś,Joanna Grzyb

doi:10.1186/s12870-015-0667-2

Abstract

BackgroundUltraviolet B (UV-B) irradiation can influence many cellular processes. Irradiation with high UV-B doses causes chlorophyll degradation, a decrease in the expression of genes associated with photosynthesis and its subsequent inhibition. On the other hand, sublethal doses of UV-B are used in post-harvest technology to prevent yellowing in storage. To address this inconsistency the effect of short, high-dose UV-B irradiation on detached Arabidopsis thaliana leaves was examined.ResultsTwo different experimental models were used. After short treatment with a high dose of UV-B the Arabidopsis leaves were either put into darkness or exposed to constant light for up to 4 days. UV-B inhibited dark-induced chlorophyll degradation in Arabidopsis leaves in a dose-dependent manner. The expression of photosynthesis-related genes, chlorophyll content and photosynthetic efficiency were higher in UV-B -treated leaves left in darkness. UV-B treatment followed by constant light caused leaf yellowing and induced the expression of senescence-related genes. Irrespective of light treatment a high UV-B dose led to clearly visible cell death 3 days after irradiation.ConclusionsHigh doses of UV-B have opposing effects on leaves depending on their light status after UV treatment. In darkened leaves short UV-B treatment delays the appearance of senescence symptoms. When followed by light treatment, the same doses of UV-B result in chlorophyll degradation. This restricts the potential usability of UV treatment in postharvest technology to crops which are stored in darkness.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0667-2) contains supplementary material, which is available to authorized users.

Highlights

Ultraviolet B (UV-B) irradiation can influence many cellular processes
An extraction buffer (4 % SDS, 2 % β-mercaptoethanol, 2 mM PMSF, 100 mM TrisHCl, pH 8,8) was added in the Effect of UV-B on dark-induced yellowing of Arabidopsis leaves Different UV-B doses were applied in order to check whether UV-B irradiation can slow down the onset of dark-induced senescence in darkened Arabidopsis leaves
The core idea of the study was to compare the effects of UV-B in dark and light conditions and that was kept in mind when setting up experimental treatments

Summary

Introduction

Ultraviolet B (UV-B) irradiation can influence many cellular processes. Irradiation with high UV-B doses causes chlorophyll degradation, a decrease in the expression of genes associated with photosynthesis and its subsequent inhibition. Sublethal doses of UV-B are used in post-harvest technology to prevent yellowing in storage. To address this inconsistency the effect of short, high-dose UV-B irradiation on detached Arabidopsis thaliana leaves was examined. Beside visible light the solar radiation which strikes the Earth’s atmosphere contains ultraviolet (UV) and infrared irradiation. UV-C, the most dangerous, is completely absorbed by the ozone layer in the atmosphere. The depletion of the ozone layer has resulted in an increase in the level of UV-B reaching the Earth’s surface.

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