A crispa null mutant facilitates identification of a crispa-like pseudogene in pea

The genomes of several legume species contain two Phantastica-like genes. Previous studies on leaf development have found that Phantastica confers leaf blade adaxial identity in plant species with simple leaves and leaflet adaxial identity in pea (Pisum sativum L.), a legume with compound leaves. Previous characterisation of the phantastica mutant of pea, crispa, showed it had radialised leaflets, but stipules were not radialised. This suggested either that mutation of a second redundant gene was required for radialisation of stipules, or, that a null mutation was required. Previously characterised crispa mutants may not have exhibited radialised stipules because they were weak alleles. In this work we show that pea has a second Phantastica-like gene, which lies on a different chromosome to Crispa. The second gene was found to be a pseudogene in several genotypes of pea, therefore it would not have a role in conferring stipule adaxial identity. A new deletion mutant, crispa-4 was identified. The mutant has radialised stipules and leaflets, showing that Crispa confers adaxial identity on both these organs in pea. The nucleotide sequence data reported here are in the EMBL and GenBank Nucleotide Databases under the accession numbers DQ486060 (JI 2822), DQ486061 (JI 15), DQ486062 (JI 281) and DQ486063 (JI 399).