Genotype-Specific Growth and Proteomic Responses of Maize Toward Salt Stress

Abstract

Salt stress in plants triggers complex physiological responses that are genotype specific. Many of these responses are either not yet described or not fully understood or both. In this work, we phenotyped three maize genotypes of the CIMMYT gene bank alongside the reference B73 genotype (NCRPIS – United States) under both control and salt-stressed conditions. We have ranked their growth potential and we observed significant differences in Na+ and Cl- ion accumulation. Genotype CML421 showed the slowest growth, while CML451 had the lowest accumulation of ions in its leaves. The phenotyping defined the right timing for the proteomics analysis, allowing us to compare the contrasting genotypes. In general 1,747 proteins were identified, of which 209 were significantly more abundant in response to salt stress. The five most significantly enriched annotations that positively correlated with stress were oxidation reduction, catabolic process, response to chemical stimulus, translational elongation and response to water. We observed a higher abundance of proteins involved in reactions to oxidative stress, dehydration, respiration, and translation. The five most significantly enriched annotations negatively correlated with stress were nucleosome organization, chromatin assembly, protein-DNA complex assembly, DNA packaging and nucleosome assembly. The genotypic analysis revealed 52 proteins that were correlated to the slow-growing genotype CML421. Their annotations point toward cellular dehydration and oxidative stress. Three root proteins correlated to the CML451 genotype were annotated to protein synthesis and ion compartmentalization. In conclusion, our results highlight the importance of the anti-oxidative system for acclimatization to salt stress and identify potential genotypic marker proteins involved in salt-stress responses.

Special issue in honour of Prof. Reto J. Strasser - Plant biomass in salt-stressed young maize plants can be modelled with photosynthetic performance

“…The results obtained in PCA indicate that the grouping of cultivars might have been caused by the differences in their respective genetic backgrounds. The maternal line of hybrid Veli is of the same origin as the B73 line from the study by Soares et al (2018). B73 was found to be among the more tolerant cultivars to the salt stress, as was the case in our study with hybrid Veli, rightmost positioned on PC1 axis in the PCA in both control and NaCl treatment (Fig.…”

“…Consequently, these metabolic alterations reflect in photosynthetic performance (Farooq et al 2015). The physiological response in maize is expected to be genotype specific, as there is a variation present in everything from Na + ion uptake and accumulation to expression of the genes included in antioxidative response and protein synthesis (Soares et al 2018). The parameter φPo is often used to express the physiological condition of a plant, but proved to be very stable under some stressful conditions, especially osmotic stress (Shabala et al 1998, Kocheva et al 2004, Deng et al 2010, Akram et al 2011, corroborated with reduced water absorption capacity of plants under the NaCl stress (Fricke et al 2006, Schleiff 2008.…”

Phosphoproteomic Analysis of Two Contrasting Maize Inbred Lines Provides Insights into the Mechanism of Salt-Stress Tolerance

“…At present, studies on the phosphorylation of maize under salt stress are still very limited [51,52]. Most studies limit themselves to a few specific proteins, and most of these proteomic and phosphoproteomics studies focus on long-term saline conditions (e.g., over 48 h of NaCl treatment) [53,54]. Under salt stress, receptors located on the cell membrane quickly sense changes in NaCl content in the external environment, and second messengers, such as Ca 2+ , inositol phosphate, ROS, and phytohormones, are rapidly produced in the cytoplasm to transduce and amplify the salt stress signals, which, in turn, induce immediate phosphorylation of protein kinases and their downstream substrates [55,56].…”

iTRAQ-Based Protein Profiling and Biochemical Analysis of Two Contrasting Rice Genotypes Revealed Their Differential Responses to Salt Stress

“…Induced expressions and differential regulation of antioxidant enzymes, including PODs, SODs, and GSTs, have been reported by several studies in rice in response to salt stress [59,60]. Furthermore, comparative proteome analysis has confirmed the involvement of ROS and redox related protein in salt stress in plants, including alfalfa [61], searocket [62], maize [63], barley [64], and wheat [65]. Moreover, as many as 56 DEPs annotated with redox reaction functions were identified in both the rice genotypes under the various salt stress levels, suggesting oxidation and reduction reactions might be the key biochemical changes taking place in rice under salinity.…”