Distinct genes produce the alcohol dehydrogenases of pollen and maternal tissues in Petunia hybrida

Analysis of cDNA clones derived from hypoxic root mRNA of Petunia hybrida has revealed the existence of a third active gene encoding alcohol dehydrogenase in petunia. A combination of RT-PCR and ADH activity gels provide evidence for the selective tissue-specific expression of these three genes in multiple floral organs and hypoxically stressed roots. Expression of adh 1 in the plant appears to be restricted to immature pollen grains; the other two genes are expressed differentially in maternal anther tissues, stigma, petals, and hypoxic root. This work underscores the utility of RT-PCR for distinguishing expression patterns of closely related genes, clarifies the expression patterns exhibited by members of this gene family, and suggests multiple functions for the adh genes of petunia.