Molecular response of canola to salt stress: insights on tolerance mechanisms

Abstract

Canola (Brassica napus L.) is widely cultivated around the world for the production of edible oils and biodiesel fuel. Despite many canola varieties being described as ‘salt-tolerant’, plant yield and growth decline drastically with increasing salinity. Although many studies have resulted in better understanding of the many important salt-response mechanisms that control salt signaling in plants, detoxification of ions, and synthesis of protective metabolites, the engineering of salt-tolerant crops has only progressed slowly. Genetic engineering has been considered as an efficient method for improving the salt tolerance of canola but there are many unknown or little-known aspects regarding canola response to salinity stress at the cellular and molecular level. In order to develop highly salt-tolerant canola, it is essential to improve knowledge of the salt-tolerance mechanisms, especially the key components of the plant salt-response network. In this review, we focus on studies of the molecular response of canola to salinity to unravel the different pieces of the salt response puzzle. The paper includes a comprehensive review of the latest studies, particularly of proteomic and transcriptomic analysis, including the most recently identified canola tolerance components under salt stress, and suggests what researchers should focus on in future studies.

Gradual Exposure to Salinity Improves Tolerance to Salt Stress in Rapeseed (Brassica napus L.)

“…In this study, the proline concentration increased significantly in both treatments and detection times. Even though controversy exists about the role of this amino acid in counteracting stress in different species, in rapeseed, proline may be involved in the response and tolerance to salt stress [10].…”

“…This crop is mainly utilized for edible oil production, its use has been also considered for the production of renewable energy, in fact the large amount of oil present in the seeds makes them suitable as oilseed and fodder crop, and for the production of biodiesel [9]. Even though many cultivars of this species were described as 'salt-tolerant', yield and growth of this crop can decline with increasing soil salinity [10].To assess the possibility to induce the tolerance to salt in cultivars of rapeseed, the effects of NaCl on plants were determined by a whole-plant assessment of agronomic parameters, used for salinity tolerance selection [11], and of physiological mechanisms underneath the response to gradual and prolonged exposure to sodium chloride.…”

“…This crop is mainly utilized for edible oil production, its use has been also considered for the production of renewable energy, in fact the large amount of oil present in the seeds makes them suitable as oilseed and fodder crop, and for the production of biodiesel [9]. Even though many cultivars of this species were described as 'salt-tolerant', yield and growth of this crop can decline with increasing soil salinity [10].…”

Stomatal and Photosynthetic Traits Are Associated with Investigating Sodium Chloride Tolerance of Brassica napus L. Cultivars

“…This oxidative stress causes decay of chlorophyll, reduces photosynthetic capacity, membrane lipid peroxidation, protein denaturation, and DNA damage [15,16]. Plants have adapted numerous advanced mechanisms to minimize oxidative injuries created by salt stress [6,7,[17][18][19][20]. One of these mechanisms is protecting cellular and sub-cellular systems from cytotoxic effects of overproduction of ROS by enhancing activities both of enzymatic and non-enzymatic antioxidant defence systems in addition to accumulation compatible solutes [15,16,[21][22][23][24].…”

“…Although rapeseeds classified as semi-tolerant plants [8], water and soil salinity are the greatest extensive problem for rapeseeds production [19]. Breeding and deployment of tolerated genotypes that have good performance under salt stress, particularly in the seedling stage can be an appropriate solution to maintain acceptable yield in the face of salt stress [17]. Therefore, it is of a great significance to develop salt-tolerant rapeseed cultivars that are needed to provide a partial solution to increase salt accumulation problem.…”