Improving Camelina seed oil production by modulating mucilage synthesis

• Applicant: Professor Dr. Björn Usadel
• Subject Area: Plant Breeding and Plant Pathology ; Plant Cell and Developmental Biology
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 284096413

• Final Report Year: 2021

Final Report Abstract

Sustainable food production in a changing climate is become more and more challenging. Camelina is an ancient oilseed crop whose cultivation is gradually being reintroduced as low-input requirements, its resistance to adverse growth conditions and the beneficial health qualities of its oil. In order to improve profitability for farmers growing this alternative crop, increasing seed oil contents is important. Camelina seeds however produce a large amount of seed mucilage and it had been shown, that ablation of arabidopsis mucilage leads to an increase in oil content. We here explored the mucilage of Cameline sativa, and could show that it is different from the one in Arabidopsis thaliana albeit containing large amounts of rhamnose and galacturonic acid. We also analyzed the seed expression of DF1 mutants in Arabidopsis thaliana using a genome wide approach and this led to the identification of a gene whose function would be consistent with mucilage synthesis and which is expressed during seed development in arabidopsis suggesting a potential function in seed coat mucilage synthesis or modification. In addition, we resequenced a population of camelina lines obtained from public seed banks and were able to call several million genomic variants in the population. The variant data suggested three major clusters in the analyzed population and revealed several highly related accessions. This variant data was then coupled to in depth phenotypic mucilage studies in the camelina population comprising seed and mucilage size as well as a detailed analysis of the mucilage composition separated into nonadherent and adherent mucilage stemming from four biological replicates. Jointly analyzing the genotypic and phenotypic data resulted in several novel QTL for camelina seed mucilage. Whilst we didn’t obtain a QTL for rhamnose which is still one major constituent of camelina mucilage, the most significant QTL was found for arabinose, a result not likely obtainable in arabidopsis, as arabidopsis mucilage contains much less arabinose. Currently the best underlying candidate gene for the arabinose QTL is a transcription factor which will be studied in more detail.

Publications

• (2018) Identification of Key Enzymes for Pectin Synthesis in Seed Mucilage Plant Physiology 178(3):1045-1064
  Voiniciuc C, Engle KA, Günl M, Dieluweit S, Schmidt MH, Yang JY, Moremen KW, Mohnen D, Usadel B
  
• (2018) Monitoring Polysaccharide Dynamics in the Plant Cell Wall. Plant Physiol. 176:2590-2600
  Voiniciuc C, Pauly M, Usadel B
  
• (2018) The Multifaceted Role of Pectin Methylesterase Inhibitors (PMEIs). Int J Mol Sci 21;19(10)
  Wormit A, Usadel B
  
• (2019) TRM4 is essential for cellulose deposition in Arabidopsis seed mucilage by maintaining cortical microtubule organization and interacting with CESA3. New Phytologist 221: 881–895
  Yang B, Voiniciuic C, Fu L, Dieluweit S, Klose H, Usadel B