Differential Response to Single and Combined Salt and Heat Stresses: Impact on Accumulation of Proteins and Metabolites in Dead Pericarps of Brassica juncea.

Jeevan R Singiri,Bupur Swetha,Gideon Grafi,Noga Sikron-Persi

doi:10.3390/ijms22137076

Jeevan R Singiri, Bupur Swetha + Show 2 more

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https://doi.org/10.3390/ijms22137076

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Abstract

Dead organs enclosing embryos, such as seed coats and pericarps, are emerging as important maternally-derived components of the dispersal unit that affect seed performance and fate. In the face of climate change and increased incidents of heatwaves, we sought to investigate the effect of salinity (S), short episodes of high temperature (HS), and combination of S + HS (SHS), at the reproductive phase, on the properties of dead pericarps of Brassica juncea. Proteome and metabolome analyses revealed multiple proteins and metabolites stored in dead pericarps whose levels and composition were altered under single and combined stress conditions. The protein profile of SHS showed a higher correlation with salt than with HS indicating the dominant effect of salt over heat stress. On the other hand, the analysis of metabolites showed that the profile of SHS has better correlation with HS than with salt. The integration of metabolic and proteomic data showed that changes in TCA cycle intermediates and certain amino acids (e.g., proline) under salt treatments (S and SHS) are highly correlated with changes in proteins involved in their biosynthetic pathways. Thus, accumulation of proteins and metabolites in dead pericarps is differently affected by single and combination of salt and heat stresses. Salinity appears to dominate plant response to combined stresses at the protein level, while heat appears to be the major factor affecting metabolite accumulation in dead pericarps.

Highlights

In virtually all agricultural regions, abiotic stresses such as drought, salinity, and temperature extremes reduce average yields for most major crop plants by more than 50%, presenting a huge barrier to feeding an ever-growing world population [1,2,3]
A principal component analysis (PCA) (Figure 2A) of the LFQ values separated all treatments with PC1 explaining 33.4% of the variance essentially separating salt treatments (S and S + HS (SHS)) from control and HS, while PC2 (17.1% of the variance) separated HS treatments from control and salt treatments
Sample-wise correlation of the differentially present (DP) proteins between treatments revealed that combined SHS is better correlated with salt (r = 0.65) than with HS (r = 0.44) (Figure 2B), implying that under combined stresses, the response to salt dominates the response to HS

Summary

Introduction

In virtually all agricultural regions, abiotic stresses such as drought, salinity, and temperature extremes reduce average yields for most major crop plants by more than 50%, presenting a huge barrier to feeding an ever-growing world population [1,2,3]. With the expected changes in global climate, environmental stresses are likely to increase in severity leading to serious effects on crop yields [4]. Climate change impacts the average annual temperature, and the frequency of incidents of extreme climate events, including heatwaves and hot spells [6,7,8]. Hot spells are the most critical factor affecting crop yield when appear in combination with other stresses and during flowering and seed development [8,9]. Exposure of mother plants to stress conditions during vegetative and reproductive stages has a great impact on progeny seed and dispersal unit properties [10,11,12]

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