Abstract
Camelina sativa is an important renewable oilseed crop for biofuel and feedstock that can relieve the reliance on petroleum-derived oils and reduce greenhouse gases and waste solids resulting from petroleum-derived oils consumption. C. sativa has recently seen revived attention due to its high oil content, high omega-3 unsaturated fatty acids, short life cycle, broader regional adaptation, and low-input agronomic requirements. However, abiotic stress such as salinity stress has imposed threatens on plant photosynthesis and growth by reducing water availability or osmotic stress, ion (Na+ and Cl−) toxicity, nutritional disorders and oxidative stress yield. There still remains much to know for the molecular mechanisms underlying these effects. In this study, a preliminary study applying 10 C. sativa cultivars to be treated under a gradient NaCl concentrations ranging from 0–250 mM and found that 100 mM was the optimal NaCl concentration to effectively differentiate phenotypic performance among different genotypes. Then, a spring panel consisting of 211 C. sativa accessions were germinated under 100 mM NaCl concentration. Six seedling germination traits, including germination rate at two stages (5-day and 9-day seedling stages), germination index, dry and fresh weight, and dry/fresh ratio, were measured. Significant correlations were found between the germination rate at two stages as well as plant biomass traits. Combining the phenotypic data and previously obtained genotypic data, a total of 17 significant trait-associated single nucleotide polymorphisms (SNPs) for the germination rate at the two stages and dry weight were identified from genome-wide association analysis (GWAS). These SNPs are located on putative candidate genes controlling plant root development by synergistically mediating phosphate metabolism, signal transduction and cell membrane activities. These identified SNPs could provide a foundation for future molecular breeding efforts aimed at improved salt tolerance in C. sativa.
Highlights
100 mM NaCl were significantly different from others, 75 mM NaCl hardly differentiated salt stress responses among the 10 different C. sativa cultivars (Figure 1b), while large phenotypic variations were observed under 100 mM NaCl, meaning that this concentration can distinguish salt-tolerant cultivars from salt-sensitive ones (Figure 1b)
The Genome-wide association studies (GWAS) analysis identified 17 significant trait-associated single nucleotide polymorphisms (SNPs) markers that were putatively related to the germination rate at two stages (5-day and 9-day after treatment) and dry weight biomass under salinity stress
The putative candidate genes that indirectly affect salt tolerance in C. sativa might be related to the mediation of phosphate metabolism, signal transductions and cell membrane activities
Summary
Due to its high level of omega-3 essential fatty acids, favorable agronomic characteristics, and potential to be a biofuel resource, C. sativa has revived researchers’ interests in recent years after being replaced by canola in the 1950s [3]. Over 90% of the total oil content in C. sativa is unsaturated fatty acids, of which omega-3 α-linolenic essential fatty acid accounts for up to 40% [3]. Advantageous agronomic characteristics such as low-input requirements for water, nutrients and pesticides, early maturity and resistance against insects and diseases [1,2,4], enable the growth of C. sativa in marginal regions without employing. Agronomy 2020, 10, 1444 arable land for food production. These oil quality characteristics, together with the agronomic benefits, make C. sativa an ideal and viable resource for both biofuel and animal feedstock
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