Diversity and plasticity of the seed specialized metabolome in Camelina species

Plants produce thousands of Specialized Metabolites (SMs), formerly called “secondary metabolites”, with diversified biological activities that are critical for the interaction of plants with their environment. SMs are synthetized in different plant organs, particularly in seeds that accumulate large amount of various SMs classes 1 (see box).

Camelina sativa is a Brassicaceae that is used for research purpose or cultivated for human/animal nutrition and industrial uses (high level of omega 3 fatty acids), see box. Nevertheless, few information were available about camelina seed co-products, including diversity and environmental plasticity of SMs such as flavonoids and glucosinolates. Cultivation of camelina and other Brassicaceae crops is accompanied by increase concerns regarding plant health for abiotic and biotic stress factors.

Specialized Metabolites (SMs) play a key role in the interactions of plants with their environment and against stress. These SMs are widely accumulated in plants and seeds of many Brassicaceae such as camelina (Camelina sativa L.). This oilseed field crop has gained a lot of interest in the past few years as a rustic oilseed crop. In a first work, Massimiliano Corso from the "Seed Development and Quality" SEEDEV team with colleagues and collaborators* analysed SMs profiles of six camelina genotypes grown in the field and harvested over five consecutive years. These analyses allowed detailed annotation of seed SMs and showed that the seed metabolome is extremely impacted by environmental factors. Among the well-identified compounds, flavonols are characterized by the highest plasticity. Alkaloids and glucosinolates were also shown to have a high and higher phenotypic plasticity than most free primary metabolites, proteins, lipids and fatty acids. This work has shown that seeds have a dynamic and plastic metabolism, with an impact on seed quality.
Besides SMs, a characterization of primary metabolites and lipids has been performed. The analyses highlighted that most specialized metabolites categories (e.g. flavonols, glucosinolates) showed a higher phenotypic plasticity with respect to most of the primary metabolites, including some sugars and fatty acids, proteins and most lipid classes (e.g. triacylglycerols), but similar plasticity compared with free amino acids and carboxylic acids. The authors highlighted major effects of the environment on the stimulation of the seed specialized metabolome suggesting that seeds show a very dynamic and inducible metabolism, with an impact on seed quality.

In a second work, scientists aim at gaining a deeper knowledge on the mechanisms controlling seed SMs biosynthesis and the impact of biotic stresses on their accumulation in camelina ssp and other Brassicaceae. They are performing an in-depth investigation of available chemical and transcriptional diversity in domesticated (C. sativa) and wild (C. microcarpa) camelina species. Copper chloride treatment (CuCl2) was used to mimic pathogen infection and to induce the seed metabolome. The analyses allowed the identification including a large number of cinnamic acids and derivatives induced by CuCl2, that might play a role in seed-pathogen interaction.

Identification of genetic factors associated to SMs accumulation in control and stress condition in seeds of camelina species that will help the development of crops better adapted to the environment and the identification of new agro-ecological solutions to improve seed quality.

* Chemistry and Metabolism plateform, IPS2 & University of Bologne, Italy

Références:
¹ M. Corso, F. Perreau, G. Mouille and L. Lepiniec, Plant Sci., 2020, 296, 110471.
² B. Alberghini, F. Zanetti, M. Corso, S. Boutet, L. Lepiniec, A. Vecchi and A. Monti, Ind. Crop. Prod., 2022, 182, 114944.
³ S. Boutet, L. Barreda, F. Perreau, J.-C. Totozafy, C. Mauve, B. Gakière, E. Delannoy, M.-L. Martin-Magniette, A. Monti, L. Lepiniec, F. Zanetti and M. Corso, Plant J., 2022, 110, 147–165.