| Mucilage is a hydrophilic polysaccharide produced in the epidermal cells of the seed coat in various plant families such as the Brassicaceae, Solanaceae, Linaceae, and Plantaginaceae. Its release upon imbibition provides a gel-like coating surrounding the seed, which facilitates its dispersal, hydration, and germination. MUCILAGE MODIFIED4 (MUM4) encodes a UDP-L-rhamnose synthase required for mucilage production. To further investigate the genes involved in mucilage biosynthesis, an enhancer/suppressor analysis of the mum4-1 phenotype was performed, resulting in the identification of new alleles of the MUM2 and MYB61 genes and six new lines that lead to further reductions in mucilage production compared to the mum4-1 single mutant, named mum enhancers (men1 to men6). Characterization of these mutants revealed reduced dormancy in the men5-1 mum4-1 double mutant, and altered seed coat cell structure, germination patterns, and root growth in the men2-1 mum4-1 double mutant. The MEN2 locus was mapped to a 4.4 Mbp region on the top arm of chromosome one. |
