Leaf proteome analysis signified that photosynthesis and antioxidants are key indicators of salinity tolerance in canola (Brassica napus L.)

Abstract

Growth and yield reduction in different crops including canola is predicted to rise due to salinity stress in coming years. Understanding responses to salt stress will help in selecting and breeding salt tolerant canola cultivars. Physiological and leaf proteomic responses of 13 cultivars of canola were investigated under salt stress. In a pot experiment, three-week-old plants were grown under normal or salt stress (150 mM NaCl) for further two weeks. Out of 13 canola cultivars, cvs DGL, Dunkled, Faisal Canola and Punjab Canola were categorized as salinity stress tolerant cultivars, while cvs Bulbul-98, Oscar, Legend and Cyclone were considered as salt sensitive. Wide genotypic variations in canola cultivars have been observed in accumulation of potassium and sodium ions in the leaves and roots. Salt tolerant cultivars accumulated low Na + in their leaves than in in roots indicating limited uptake of Na + at root level with subsequent its transport to shoot. Moreover, salt tolerant cultivars had greater Na + discriminating capacity against K + . Salt tolerant cultivars were higher in leaf relative water content. Although Fv/Fm did not change in canola cultivars due to salt stress, Fv/Fo and PIABS decreased considerably in all cultivars indicating important indicators of salt stress. Salt stress increased Vj, VI, ABS/RC, TRo/RC and DIo/RC but it decreased ETo/RC which indicated that salt stress damaged the donor end of PSII (oxygen evolving complex) and reaction centers. Such adverse effects were maximal in salt sensitive cultivar Legend while minimal effects were observed in salt tolerant canola cultivars Faisal Canola, DGL and Dunkled. From comparative proteome analysis, it is obvious that 18 differentially expressed proteins in canola cultivars are mainly related with antioxidative defense system, photosynthesis and gene regulation. In addition, expression of these proteins was greater in salt tolerant cultivars. Cellular enegetics related proteins were downregulated particularly in salt sensitive cultivars due to salt stress. It is concluded that antioxidative defence system and photosynthesis are major componens of salt tolerance in canola in addition to salt exclusion. In addition, physiological studies complemented with proteomics will help in understanding detailed mechanism of salt tolerance.

Identification of novel source of salt tolerance in local bread wheat germplasm using morpho-physiological and biochemical attributes

“…After introgression of this trait, they developed salinity stress tolerant durum and bread wheat lines named Nax1 and Nax2 19 . It is important to mention here that genetic variation for salinity stress tolerance in a crop species cannot be explained due to one or two traits 2 , 20 , 21 . Plant’s ability to accumulate organic osmolytes such as soluble sugars and amino acids, activation of antioxidants to scavenge reactive oxygen species (ROS), down-regulating electron transport through photosystems to lower ROS generation are some important components of salt tolerance 1 10 , 20 , 22 .…”

RNAseq Analysis Reveals Altered Expression of Key Ion Transporters Causing Differential Uptake of Selective Ions in Canola (Brassica napus L.) Grown under NaCl Stress

“…In recent years, physiological processes complemented with proteome profiling and/or transcriptome mapping in plants have gained popularity to explore mechanisms of salt tolerance [ 15 , 16 , 17 , 18 ]. Next-generation sequencing (NGS) has become a potential technique to evaluate molecular profiles for crop plants [ 19 ].…”

Salt stress proteins in plants: An overview

“…Carbon or carbohydrate metabolism occurs in the chloroplast, mitochondria, and cytosol of plant cells via the Calvin cycle, pentose phosphate pathway, glycolysis, and Krebs cycle (Barkla et al, 2013b;Taiz et al, 2015). Therefore, salt stress downregulates or upregulates several proteins associated with these metabolic pathways, as observed in rice (Nam et al, 2012;Liu et al, 2014), sorghum (Ngara et al, 2012), alfalfa (Xiong et al, 2017), canola (Iqbal et al, 2019), chickpea (Arefian et al, 2019) and Eutrema salsugineum (Goussi et al, 2021). Several studies have reported that salt stress reduces proteins related to chlorophyll biosynthesis, but increases thylakoidal proteins related to the light reaction (Barkla et al, 2013b; and references there in).…”

“…Plants adapt to salinity stress by regulating the uptake and transport of Na + and K + ions, activating enzymes to scavenge reactive oxygen species (ROS), and improving osmotic adjustment (Kalaji and Pietkiewicz, 1993;Ashraf, 2009;Athar and Ashraf, 2009;Munns et al, 2020b). Proteins regulate these processes under normal and salt stress conditions (Li et al, 2017b;Li et al, 2017c;Iqbal et al, 2019), which are responsible for regulating cellular metabolism, organic and inorganic solute transport, water transport, osmoregulation, redox balance, sensing and signalling, hormonal balance, cell division, cell enlargement, and growth and development (Zhang et al, 2012a;Li et al, 2017c). In this review, we discussed the effect of salt stress on total soluble proteins, composition of proteins of different molecular weights, proteins related to various physiological and biochemical processes in halophytes and glycophytes or salt tolerant and salt sensitive cultivars of same species (Bose et al, 2017;Negrão et al, 2017;Pailles et al, 2020).…”