Abstract
The Arabidopsis SHEPHERD (SHD) gene encodes an Hsp90-like molecular chaperone resident in the ER. The shd-1 mutant from Ws shows clavata (clv)-like phenotype, whereas the shd-2 from Columbia (Col) does not. When we crossed shd-1 with Col, only less than a half of shd homozygotes in F2 population showed the clv-like phenotype. We speculated an enhancer is present in the Ws genome that makes shd-1 be such phenotype. A linkage analysis revealed the enhancer tightly linked to the CLV2 gene. Furthermore, the Col-type CLV2 introduced into shd-1 suppressed the clv-like phenotype. Therefore, we conclude that only Ws-type CLV2 requires the SHD for its function. The CLV2 has been reported to harbor many polymorphisms accompanying amino acid substitutions. Our results suggest the chaperone function of SHD allows these polymorphisms. We think CLV2 seems to be an example of the theory, in which Hsp90 allows the storage and release of genetic variation.
