Members of the Brassicaceae family have the ability to regulate pollination events occurring on the stigma surface. In Brassica species, self-pollination leads to an allele-specific interaction between the pollen small cysteine-rich peptide ligand (SCR/SP11) and the stigmatic S-receptor kinase (SRK) that activates the E3 ubiquitin ligase ARC1 (Armadillo repeat-containing 1), resulting in proteasomal degradation of various compatibility factors including glyoxalase I (GLO1) which is necessary for successful pollination. In Brassica napus, the suppression of GLO1 was sufficient to reduce compatibility, and overexpression of GLO1 in self-incompatible Brassica napus stigmas resulted in partial breakdown of the self-incompatibility response. Here, we verified if BnGLO1 could function as a compatibility factor in the artificial self-incompatibility system of Arabidopsis thaliana expressing AlSCRb, AlSRKb and AlARC1 proteins from A. lyrata. Overexpression of BnGLO1 is sufficient to breakdown self-incompatibility response in A. thaliana stigmas. Therefore, GLO1 has an indisputable role as a compatibility factor in the stigma in regulating pollen attachment and pollen tube growth. Lastly, this study demonstrates the usefulness of an artificial self-incompatibility system in A. thaliana for interspecific self-incompatibility studies.
Keywords: Arabidopsis; Brassica; Glyoxalase I; Pollen–pistil interactions; Pollination; Self-incompatibility.