Limits...
Reduction of photosynthetic sensitivity in response to abiotic stress in tomato is mediated by a new generation plant activator.

Wargent JJ, Pickup DA, Paul ND, Roberts MR - BMC Plant Biol. (2013)

Bottom Line: Yield losses as a result of abiotic stress factors present a significant challenge for the future of global food production.Salinity treatment led to a maximal 47% reduction in net photosynthetic rate 8 d following NaCl treatment, yet in Alethea pre-treated seedlings, sensitivity to salinity stress was markedly reduced during the experimental period.Alethea affected the expression of genes related to biotic stress, ethylene signalling, cell wall synthesis, redox signalling and photosynthetic processes.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Yield losses as a result of abiotic stress factors present a significant challenge for the future of global food production. While breeding technologies provide potential to combat negative stress-mediated outcomes over time, interventions which act to prime plant tolerance to stress, via the use of phytohormone-based elicitors for example, could act as a valuable tool for crop protection. However, the translation of fundamental biology into functioning solution is often constrained by knowledge-gaps.

Results: Photosynthetic and transcriptomic responses were characterised in young tomato (Solanum lycopersicum L.) seedlings in response to pre-treatment with a new plant health activator technology, 'Alethea', followed by a subsequent 100 mM salinity stress. Alethea is a novel proprietary technology composed of three key constituent compounds; the hitherto unexplored compound potassium dihydrojasmonate, an analogue of jasmonic acid; sodium benzoate, a carboxylic acid precursor to salicylic acid, and the α-amino acid L-arginine. Salinity treatment led to a maximal 47% reduction in net photosynthetic rate 8 d following NaCl treatment, yet in Alethea pre-treated seedlings, sensitivity to salinity stress was markedly reduced during the experimental period. Microarray analysis of leaf transcriptional responses showed that while salinity stress and Alethea individually impacted on largely non-overlapping, distinct groups of genes, Alethea pre-treatment substantially modified the response to salinity. Alethea affected the expression of genes related to biotic stress, ethylene signalling, cell wall synthesis, redox signalling and photosynthetic processes. Since Alethea had clear effects on photosynthesis/chloroplastic function at the physiological and molecular levels, we also investigated the ability of Alethea to protect various crop species against methyl viologen, a potent generator of oxidative stress in chloroplasts. Alethea pre-treatment produced dramatic reductions in visible foliar necrosis caused by methyl viologen compared with non-primed controls.

Conclusions: 'Alethea' technology mediates positive recovery of abiotic stress-induced photosynthetic and foliar loss of performance, which is accompanied by altered transcriptional responses to stress.

Show MeSH

Related in: MedlinePlus

Hierarchical clustering of differentially-regulated genes. Heatmap display of the clustered non-redundant list of differentially-regulated probe sets derived from Rank Products analysis. Colour scheme represents standardised expression signals relative to the mean (white) for each probe set, with increasing red intensity representing high levels of expression, and blue, low expression relative to the mean. Clusters of genes showing different patterns of regulation are identified at the right of the cluster diagram, and the respective trends in expression for each cluster are illustrated by mean expression profiles for standardised data (± standard deviation) for all genes within each cluster. Notation designates Pre-treatment/Treatment, where W = water, A = Alethea, S = salt.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3733976&req=5

Figure 2: Hierarchical clustering of differentially-regulated genes. Heatmap display of the clustered non-redundant list of differentially-regulated probe sets derived from Rank Products analysis. Colour scheme represents standardised expression signals relative to the mean (white) for each probe set, with increasing red intensity representing high levels of expression, and blue, low expression relative to the mean. Clusters of genes showing different patterns of regulation are identified at the right of the cluster diagram, and the respective trends in expression for each cluster are illustrated by mean expression profiles for standardised data (± standard deviation) for all genes within each cluster. Notation designates Pre-treatment/Treatment, where W = water, A = Alethea, S = salt.

Mentions: Hierarchical clustering was performed to visualise the patterns of regulation of the differentially-expressed genes. By visual inspection of the resulting cluster diagram (Figure 2), we identified nine gene clusters representing distinct combinations of responses to Alethea and salinity (a full list of annotated genes and associated GO terms for each cluster are available in Additional file 3). The largest two clusters (Clusters 4 and 7) represent genes which respond to Alethea treatment independently of salinity stress. Clusters 1 and 8 meanwhile, contain genes that are regulated by salinity. These responses are largely independent of Alethea, although there is some evidence of an attenuation of the magnitude expression of salt-induced genes by Alethea pre-treatment. Of the remaining clusters, clusters 2,6 and 9 contain genes that show additive responses to salt and Alethea. Two clusters, however, represent more complex interactions between salt and Alethea. Cluster 5 contains genes that are up-regulated by salinity in control plants, but not in plants pre-treated with Alethea, whilst cluster 3 contains genes down-regulated by salt only in control plants. Alethea therefore appears to attenuate the salt-responsiveness of these groups of genes. To validate the microarray data, we selected representative genes regulated by Alethea and/or salinity for analysis by reverse transcription (RT) PCR. The results (Figure 3) generally show close agreement with the array data.


Reduction of photosynthetic sensitivity in response to abiotic stress in tomato is mediated by a new generation plant activator.

Wargent JJ, Pickup DA, Paul ND, Roberts MR - BMC Plant Biol. (2013)

Hierarchical clustering of differentially-regulated genes. Heatmap display of the clustered non-redundant list of differentially-regulated probe sets derived from Rank Products analysis. Colour scheme represents standardised expression signals relative to the mean (white) for each probe set, with increasing red intensity representing high levels of expression, and blue, low expression relative to the mean. Clusters of genes showing different patterns of regulation are identified at the right of the cluster diagram, and the respective trends in expression for each cluster are illustrated by mean expression profiles for standardised data (± standard deviation) for all genes within each cluster. Notation designates Pre-treatment/Treatment, where W = water, A = Alethea, S = salt.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3733976&req=5

Figure 2: Hierarchical clustering of differentially-regulated genes. Heatmap display of the clustered non-redundant list of differentially-regulated probe sets derived from Rank Products analysis. Colour scheme represents standardised expression signals relative to the mean (white) for each probe set, with increasing red intensity representing high levels of expression, and blue, low expression relative to the mean. Clusters of genes showing different patterns of regulation are identified at the right of the cluster diagram, and the respective trends in expression for each cluster are illustrated by mean expression profiles for standardised data (± standard deviation) for all genes within each cluster. Notation designates Pre-treatment/Treatment, where W = water, A = Alethea, S = salt.
Mentions: Hierarchical clustering was performed to visualise the patterns of regulation of the differentially-expressed genes. By visual inspection of the resulting cluster diagram (Figure 2), we identified nine gene clusters representing distinct combinations of responses to Alethea and salinity (a full list of annotated genes and associated GO terms for each cluster are available in Additional file 3). The largest two clusters (Clusters 4 and 7) represent genes which respond to Alethea treatment independently of salinity stress. Clusters 1 and 8 meanwhile, contain genes that are regulated by salinity. These responses are largely independent of Alethea, although there is some evidence of an attenuation of the magnitude expression of salt-induced genes by Alethea pre-treatment. Of the remaining clusters, clusters 2,6 and 9 contain genes that show additive responses to salt and Alethea. Two clusters, however, represent more complex interactions between salt and Alethea. Cluster 5 contains genes that are up-regulated by salinity in control plants, but not in plants pre-treated with Alethea, whilst cluster 3 contains genes down-regulated by salt only in control plants. Alethea therefore appears to attenuate the salt-responsiveness of these groups of genes. To validate the microarray data, we selected representative genes regulated by Alethea and/or salinity for analysis by reverse transcription (RT) PCR. The results (Figure 3) generally show close agreement with the array data.

Bottom Line: Yield losses as a result of abiotic stress factors present a significant challenge for the future of global food production.Salinity treatment led to a maximal 47% reduction in net photosynthetic rate 8 d following NaCl treatment, yet in Alethea pre-treated seedlings, sensitivity to salinity stress was markedly reduced during the experimental period.Alethea affected the expression of genes related to biotic stress, ethylene signalling, cell wall synthesis, redox signalling and photosynthetic processes.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Yield losses as a result of abiotic stress factors present a significant challenge for the future of global food production. While breeding technologies provide potential to combat negative stress-mediated outcomes over time, interventions which act to prime plant tolerance to stress, via the use of phytohormone-based elicitors for example, could act as a valuable tool for crop protection. However, the translation of fundamental biology into functioning solution is often constrained by knowledge-gaps.

Results: Photosynthetic and transcriptomic responses were characterised in young tomato (Solanum lycopersicum L.) seedlings in response to pre-treatment with a new plant health activator technology, 'Alethea', followed by a subsequent 100 mM salinity stress. Alethea is a novel proprietary technology composed of three key constituent compounds; the hitherto unexplored compound potassium dihydrojasmonate, an analogue of jasmonic acid; sodium benzoate, a carboxylic acid precursor to salicylic acid, and the α-amino acid L-arginine. Salinity treatment led to a maximal 47% reduction in net photosynthetic rate 8 d following NaCl treatment, yet in Alethea pre-treated seedlings, sensitivity to salinity stress was markedly reduced during the experimental period. Microarray analysis of leaf transcriptional responses showed that while salinity stress and Alethea individually impacted on largely non-overlapping, distinct groups of genes, Alethea pre-treatment substantially modified the response to salinity. Alethea affected the expression of genes related to biotic stress, ethylene signalling, cell wall synthesis, redox signalling and photosynthetic processes. Since Alethea had clear effects on photosynthesis/chloroplastic function at the physiological and molecular levels, we also investigated the ability of Alethea to protect various crop species against methyl viologen, a potent generator of oxidative stress in chloroplasts. Alethea pre-treatment produced dramatic reductions in visible foliar necrosis caused by methyl viologen compared with non-primed controls.

Conclusions: 'Alethea' technology mediates positive recovery of abiotic stress-induced photosynthetic and foliar loss of performance, which is accompanied by altered transcriptional responses to stress.

Show MeSH
Related in: MedlinePlus