ELECTROPHORETIC AND IMMUNOLOGICAL STUDIES OF PROLAMINS IN THE POACEAE .2. PHYLOGENETIC AFFINITIES OF THE ARISTIDEAE

The Aristideae are considered to include Aristida, Stipagrostis and Sartidia. The phylogenetic affinity of this tribe in the Poaceae remains controversial. To provide additional insight into the appropriate placement of the Aristideae, 21 species representing Aristida, Stipagrostis, Chloridoideae, Arundinoideae, and Hordeum (Pooideae) were analyzed for prolamin size heterogeneity and immunological cross-reactivities. Aristida species revealed species-specific prolamin subunit profiles. Immunological cross-reactivities measured by the enzyme-linked immunosorbent assay (ELISA) and immunoblotting demonstrated that Aristida was distinct from the Arundinoideae and Chloridoideae. The prolamin profile of Stipagrostis differed from those of Aristida and the genus clustered with the Chloridoideae on the basis of immunological cross-reactivities. The data indicate the heterogeneity of the Aristideae, and suggest an isolated position for Aristida in the Poaceae rather than its placement in either the Arundinoideae or Chloridoideae.