Molecular Lesions in BRI1 and Its Orthologs in the Plant Kingdom.

Brassinosteroids (BRs) are an essential group of plant hormones regulating numerous aspects of plant growth, development, and stress responses. BRI1, along with its co-receptor BAK1, are involved in brassinosteroid sensing and early events in the BR signal transduction cascade. Mutational analysis of a particular gene is a powerful strategy for investigating its biochemical role. Molecular genetic studies, predominantly in , but progressively in numerous other plants, have identified many mutants of the gene and its orthologs to gain insight into its structure and function. So far, the plant kingdom has identified up to 40 alleles in Arabidopsis and up to 30 orthologs in different plants. These alleles exhibit phenotypes that are identical in terms of development and growth. Here, we have summarized alleles in Arabidopsis and its orthologs present in various plants including monocots and dicots. We have discussed the possible mechanism responsible for the specific allele. Finally, we have briefly debated the importance of these alleles in the research field and the agronomically valuable traits they offer to improve plant varieties.