Project description:Transcriptional profiling of fully developed leaves of Arabidopsis Col0 after 30 min of high-light stress (1000 umol*m-2*s-1). Goal was to find early transcriptional responses to immediate high-light stress, before acclimation responses appear.
Project description:Plants acclimate to environmental fluctuations by transitory reconfigurations the homeostatic network. Primary studies suggested that transcriptome responses to deal with fluctuations in light intensity and temperature tend to reversibility after stress removal in the model plant Arabidopsis thaliana. To gain more insight into this pattern in the context of acclimation, RNA-Seq analysis were conducted in Arabidopsis thaliana after different abiotic stress treatments consisting in high light (HL), high humidity, drought, heat, cold and combinations among factors or after recovery periods. Our transcriptome study is in line of a general pattern wherby transcriptome changes in response to adverse environments are prone to return to the basal state during the de-acclimation phase.
Project description:Dynamic acclimation of photosynthesis plays an important role in increasing plant fitness under variable light environments. Acclimation is mediated by a glucose-6-phosphate/phosphate translocator, GPT2. This study examined whether plants lacking GPT2, which are defective in acclimation to increases in light, are more susceptible to oxidative stress. To understand this, we used the model plant of Arabidopsis thaliana (accession Wassilewskija-4 (Ws-4)) and compared this to mutants lacking GPT2. Plants were grown at low light (100 μmol m−2 s−1) for 7 weeks. For acclimation experiments, a set of plant from low light was transferred to 400 μmol m−2 s−1 for 7 days. Microarray analysis showed that gpt2 plants showed a greater induction of stress related genes relative to WT.
Project description:Earlier findings indicated that light plays a critical role in the development of frost tolerance in winter cereals. However, the exact mechanism is still poorly understood. In the present work the effects of light during the cold acclimation period were studied in chilling-sensitive maize plants. The results show that although exposure to relatively high light intensities during cold acclimation at 15 °C causes various stress symptoms, it enhances the effectiveness of acclimation to chilling conditions (5 °C in the light). Interestingly, certain stress responses were light-dependent not only in the leaves, but also in the roots. A microarray study was also conducted to achieve a better understanding of the interaction of low temperature and light intensity during the cold hardening period. Numerous genes significantly differentially expressed were observed in almost all assimilation and metabolic pathways. Acclimation at moderately low temperature and low light intensity reduced the level of soluble sugars, while chilling increased it. Greater accumulation during hardening was detected at relatively high light intensity. It seems that the photoinhibition induced by low temperature is a necessary evil for cold acclimation processes in plants.
Project description:Exposure of mature fully expanded leaves of Arabidopsis to a 7.5 fold increased light intensity above growth light conditions (high light; HL) tirggers stress defensive responses but also initiates cellular processes, that if such conditions persist, can lead to increased photosynthetic capacity. This process is called dynamic acclimation. By using variational Bayesian state space modelling on eariler GEO deposited time series HL data (see GSE78251) a gene regulatory network of (co) transcription factor genes was inferred. The most connected gene in this network is BBX32, which was subequently shown to be a negative regulator of dynamic acclimation. Also present in the inferred network is HY5, which is known from studies on seedling photomorphogenesis to be antagonistic in its action to BBX32. Subsequently, it was demonstrated that HY5 is indeed a positive regulator of dynamic acclimation. This RNAseq-based study seeks to provide gene expression data that will help to link the immediate impact of these genes on the HL transcriptome to the longer term (several days) physiological manifestation of dynamic acclimation.
Project description:Typically, when fully developed leaves of Arabidopsis thaliana are exposed to an increase in light intensity, they are able to increase their photosynthetic capacity in a process known as dynamic acclimation. Fully developed leaves of Arabidopsis thaliana were exposed to a fourfold increase in light intensity for 7 days to induce high light acclimation. This treatment was subjected to wild-type and a non-acclimating mutant lacking the gpt2 gene. The proteomic responses of the leaves were investigated using label-free mass spectrometry. A large reorganisation of the proteome was shown, with increases in the abundance of proteins of photosynthesis and carbon metabolism. Subtle differences were seen between the WT and gpt2 mutant: in the mutant, an increased stress response was seen, and some differences in the responses of metabolism. Proteomic responses generally correlated with physiological responses.
Project description:Typically, when fully developed leaves of Arabidopsis thaliana are exposed to an increase in light intensity, they are able to increase their photosynthetic capacity in a process known as dynamic acclimation. Fully developed leaves of Arabidopsis thaliana were exposed to a fourfold increase in light intensity for 7 days to induce high light acclimation. This treatment was subjected to wild-type and a non-acclimating mutant lacking the gpt2 gene. The proteomic responses of the leaves were investigated using label-free mass spectrometry. A large reorganisation of the proteome was shown, with increases in the abundance of proteins of photosynthesis and carbon metabolism. Subtle differences were seen between the WT and gpt2 mutant: in the mutant, an increased stress response was seen, and some differences in the responses of metabolism. Proteomic responses generally correlated with physiological responses.
Project description:Plants growing in the field are subjected to high light intensities that are often accompanied by high temperatures. In this work, we analyzed transcriptomic responses of wild type Col plants and mutants defective in the transcription factor WRKY48 to understand why wrky48 mutants are more tolerant to the combination of high temperatures and high light stress. Our results indicate that jasmonic acid accumulation induced by the combination of high light and heat stress could repress WRKY48 expression, enabling the expression of acclimation genes to this stress combination.
Project description:High light stress in subtropical and tropical regions strongly limits agricultural production due to photo-oxidative damage, decreased growth and yield. Here, we investigated whether beneficial microbes can protect plants under high light stress. We show that Enterobacter sp. SA187 (SA187) assists Arabidopsis in maintaining growth under high light stress, reducing the accumulation of reactive oxygen species (ROS) and maintaining photosynthesis. Under high light stress, SA187 induces dynamic transcriptional changes related to a fortified iron metabolism and redox system in Arabidopsis. A genetic analysis shows that SA187-induced plant high light stress tolerance is mediated by ethylene signaling via the transcription factor EIN3 to enhance iron metabolism. In summary, we show that Arabidopsis interaction with SA187 results in sustained photosynthesis under high light stress suggesting that beneficial microbes could be effective and cheap means for enhancing high light stress tolerance in crops.