Effect of light on the gene expression and hormonal status of winter and spring wheat plants during cold hardening

Abstract

The effect of light on gene expression and hormonal status during the development of freezing tolerance was studied in winter wheat (Triticum aestivum var. Mv Emese) and in the spring wheat variety Nadro. Ten-day-old plants (3-leaf stage) were cold hardened at 5°C for 12 days under either normal (250 µmol m(-2) s(-1) ) or low (20 µmol m(-2) s(-1) ) light conditions. Comprehensive analysis was carried out to explore the background of frost tolerance and the differences between these wheat varieties. Global genome analysis was performed, enquiring about the details of the cold signaling pathways. The expression level of a large number of genes is affected by light, and this effect may differ in different wheat genotypes. Photosynthesis-related processes probably play a key role in the enhancement of freezing tolerance; however, there are several other genes whose induction is light-dependent, so either there is cross-talk between signaling of chloroplast originating and other protective mechanisms or there are other light sensors that transduce signals to the components responsible for stress tolerance. Changes in the level of both plant hormones (indole-3-acetic acid, cytokinins, nitric oxide and ethylene precursor 1-aminocyclopropane-1-carboxylic acid) and other stress-related protective substances (proline, phenolics) were investigated during the phases of the hardening period. Hormonal levels were also affected by light and their dynamics indicate that wheat plants try to keep growing during the cold-hardening period. The data from this experiment may provide a new insight into the cross talk between cold and light signaling in wheat.

Reduced light and moderate water deficiency sustain nitrogen assimilation and sucrose degradation at low temperature in durum wheat

“…Changes in the gene expression suggests potential changes at metabolic level (Majláth et al, 2012). In bread wheat, mild drought at low temperature was contributed to the homeostasis of oxidative metabolism and relatively better photosynthesis, and hence to less grain yield loss under late spring low temperature stress, however, the effect of light was not studied (Li et al, 2014).…”

Salicylic acid and photosynthesis: signalling and effects

“…11 Several stressors may directly or indirectly severely affect the photosynthetic processes (Majláth et al 2012;Ashraf and Harris 2013). It has been well documented that exogenous SA may alleviate the damaging effects of various stress factors, and this protection can also be manifested in higher photosynthetic capacity (Horváth et al 2007, Hayat et al 2010, Radwan and Soltan 2012, Sasheva et al 2013, Tirani et al 2013.…”

“…They are also indicators of plant stress responses upon variation of light, salinity, temperature, radiation, pollutions (Vogt 2010;Kosova et al 2012;Majláth et al 2012). Salicylic acid (SA) is a monohydroxy-benzoic acid, which is well-known signalling molecule playing role in local and systemic acquired resistance against pathogens as well as in acclimation to certain abiotic stressors (Raskin 1992a;Horváth et al 2007;Szalai et al 2013;Pál et al 2013).…”

Role of salicylic acid in acclimation to low temperature

“…However, after prolonged cold acclimation, the content of phenolics was significantly lower in genotypes tolerant to freezing than in susceptible genotypes, while the activity of the phenylalanine ammonia-lyase enzyme was significantly higher. Plant growth substances such as abscisic acid, cytokinins or gibberellic acid also modify the response of plants to low temperature stress (Pál et al, 2011;Majláth et al, 2012). Furthermore, the treatment of wheat seeds with SA caused the accumulation of abscisic acid and indoleacetic acid (Shakirova et al, 2002), and this effect may also have a direct or indirect role in the altered tolerance to low temperature stress.…”