Salinity Tolerance in Canola: Insights from Proteomic Studies

Salinity considerably lowers crop yield worldwide. Production of salt stress-tolerant species will be essential to maintain the food supply in the coming decades. Brassicas, including various members of the family Brassicaceae, are very necessary sources of human food. Importantly, the key crop species that are members of the Brassicaceae family are genetically diverse and therefore their response reaction and adaptation to salinity varies greatly. Canola (Brassica napus L.) is commonly grown for edible oils and other uses such as biodiesel fuel production. Although most types of canola are identified as salt-resistant, plant yield and development are reduced significantly by rising salinity levels. In saline situations, the plant’s genome supports a range of physiological changes in some plant characteristics. Since the function of genes cannot indicate the exact condition of cells, proteomic approaches are emerged as methods to investigate the plant’s responses to stresses in the molecular levels. Exploring the proteome complements research at the genome and transcriptome level and helps elucidate the mechanism of salt tolerance in plants. Proteins are reliable indicators of salinity responses, as they are directly involved in forming the new phenotype providing adaptation to salinity. In this chapter, we review the response of the rapeseed proteome to salinity stress.

Genome Sequence of the Euryhaline Javafish Medaka, Oryzias javanicus: A Small Aquarium Fish Model for Studies on Adaptation to Salinity

The genus Oryzias consists of 35 medaka-fish species each exhibiting various ecological, morphological and physiological peculiarities and adaptations. Beyond of being a comprehensive phylogenetic group for studying intra-genus evolution of several traits like sex determination, behavior, morphology or adaptation through comparative genomic approaches, all medaka species share many advantages of experimental model organisms including small size and short generation time, transparent embryos and genome editing tools for reverse and forward genetic studies. The Java medaka, Oryzias javanicus, is one of the two species of medaka perfectly adapted for living in brackish/sea-waters. Being an important component of the mangrove ecosystem, O. javanicus is also used as a valuable marine test-fish for ecotoxicology studies. Here, we sequenced and assembled the whole genome of O. javanicus, and anticipate this resource will be catalytic for a wide range of comparative genomic, phylogenetic and functional studies. Complementary sequencing approaches including long-read technology and data integration with a genetic map allowed the final assembly of 908 Mbp of the O. javanicus genome. Further analyses estimate that the O. javanicus genome contains 33% of repeat sequences and has a heterozygosity of 0.96%. The achieved draft assembly contains 525 scaffolds with a total length of 809.7 Mbp, a N50 of 6,3 Mbp and a L50 of 37 scaffolds. We identified 21454 predicted transcripts for a total transcriptome size of 57, 146, 583 bps. We provide here a high-quality chromosome scale draft genome assembly of the euryhaline Javafish medaka (321 scaffolds anchored on 24 chromosomes (representing 97.7% of the total bases)), and give emphasis on the evolutionary adaptation to salinity.