Domestication influences morphological and physiological responses to salinity in Brassica oleracea seedlings

Wild germplasm can potentially be used to improve the salt tolerance of crops by the identification of useful genes and incorporation of these into salinity-sensitive cultivars.

Brassica oleracea is a species that includes many common vegetable and forage crops grown worldwide, including cabbage, broccoli, cauliflower and brussel sprouts. Wild B. oleracea grows in saline environments, inhabiting sea cliffs across Europe, where it cannot evade the effects of salt. Salinity is one of the most limiting factors for crop production and is expected to become even more of a problem in the future, particularly in intensively cropped and densely populated areas. Understanding how non-domesticated plants that survive in saline environments manage sodium toxicity could be useful for determining the mechanism of stress tolerance in Brassica oleracea, and could help to identify useful traits to improve salt tolerance in Brassica crops.

Brassica oleracea plants growing on the sea cliffs in Foz, Lugo, Spain. Wild types, adapted to survive and grow in saline habitats, could be crucial to increase the genetic variability in relation to salinity tolerance in Brassica crops. Image credit: M. Lema.

A recent study by Lema et al., and published in AoBP, investigates the influence of domestication status (wild, landrace or cultivar) on the response of different B. oleracea crops (cabbage and kale) to salinity. The authors assessed salinity tolerance through measurement of seed germination, plant growth, water content and mineral concentration parameters at the seedling stage. In both kale and cabbage, differences in domestication status and salt stress significantly affected all major process such as germination, changes in dry matter, water relations and mineral uptake. Specifically, wild plants are more succulent than cultivated plants and have a higher capacity to maintain lower Na+ concentrations in their shoots in response to increasing levels of salinity. This study reveals that wild B. oleracea has evolved various adaptation mechanisms, such as exclusion of sodium from shoots and increasing succulence, to cope with high salinity levels in the long term. The wild germplasm has the potential to improve the salt tolerance of crops by the identification of useful genes and incorporation of these into salinity-sensitive cultivars.

Researcher highlight

Margarita Lema is a plant breeder and geneticist involved in the design of crop genotypes adapted to production in specific environments, including those with reduced inputs. She graduated at the University of Santiago de Compostela (Spain) and carried out two postdoctoral stays at the University of Idaho and California-Davis (USA). At present, she is researching at the Department of Functional Biology at the USC.

Margarita is interested in understanding the physiological responses to Genotype X Environment interactions that could lead to plant improvements that increase crop productivity and environmental adaptation. She is also involved in studying the physiological responses of invasive and endemic plants to global change, the biological control of invasive plant species, and the application of spectral remote sensing for agricultural and forestry production.