Biology of the seed coat

Project Leader

Martin Sagasser, PhD


Seed coats of most plants contain secondary metabolites called flavonoids (comprising e.g. flavonols, proanthocyanidins or condensed tannins). They help to protect the seed from biotic and abiotic stresses like pathogens or light, thus influencing important seed characteristics like germination rate and storability. From the human perspective, flavonoids are often desired ingredients, associated with health promoting effects, which are mainly due to their antioxidative properties. However, in other cases it is their dark colouration and bitter and adstringent taste that limits the use of seed and seed-derived products in food and feed.

Therefore, our aim is to learn more about the biosynthesis of seed coat flavonoids and its regulation. To this end we make use of mutants of the model plant Arabidopsis thaliana with defects in certain steps of seed coat pigmentation. These mutants are named transparent testa (abbreviated tt) as the lack of pigments results in a transparent seed coat (latin: testa). Currently our main focus is to unravel the functions of WIP Proteins, which make up a small and so far poorly characterized family of plant proteins containing zinc finger domains.


Appelhagen I, Nordholt N, Seidel T, Spelt K, Koes R, Quattrochio F, Sagasser M, Weisshaar B (2015)
TRANSPARENT TESTA 13 is a tonoplast P3A -ATPase required for vacuolar deposition of proanthocyanidins in Arabidopsis thaliana seeds. Plant J 82(5): 840-9. PubMed

Appelhagen I, Thiedig K, Nordholt N, Schmidt N, Huep G, Sagasser M, Weisshaar B (2014)
Update on transparent testa mutants from Arabidopsis thaliana: characterisation of new alleles from an isogenic collection. Planta 240(5): 955-70. PubMed

Seed Coat
Crop Genomics