Abstract
Pistillody, homeotic transformation of stamens into pistil-like structures, has been reported in the cytoplasmic substitution (alloplasmic) lines of bread wheat (Triticum aestivum) with the cytoplasm of wild relative species Aegilops crassa. The induction of pistillody is suppressed by the Rfd1 gene located on the long arm of chromosome 7B in wheat cultivar Chinese Spring (CS). Because of the absence of Rfd1, the alloplasmic line of CS ditelosomic 7BS ((cr)-CSdt7BS) lacking the long arm of chromosome 7B exhibits pistillody in all florets, whereas the euplasmic CS ditelosomic 7BS (CSdt7BS) with wheat cytoplasm forms normal stamens. Pistillody is caused by the alteration of the class B MADS box gene expression pattern, which should be due to the function of mitochondrial gene(s) in the Ae. crassa cytoplasm. Here, we identified mitochondrial chimeric genes, orf256-coxI and nad1-ND6, specifically expressed in the young spike of the pistillody line by using the cDNA subtraction technique.
