Isolation of an ILR1 auxin conjugate hydrolase homolog from Arabidopsis suecica

We have isolated a homolog of the Arabidopsis thaliana IAA amidohydrolase ILR1 from the related species Arabidopsis suecica. Employing PCR primers targeted to the 5′ and 3′ untranslated regions of ILR1, A. suecica produced an amplified, genomic product (sILR1) of 2027 bp. The cloned sILR1 gene was sequenced, and the DNA homology between sILR1 and ILR1 found to be 98%. The sILR1 cDNA was isolated using RT-PCR, cloned and sequenced. The sILR1 cDNA was found to have 98% homology to its homolog ILR1 both at the DNA and amino acid level. The sILR1 mRNA transcript was found to be expressed in A. suecica tissues at ages 5, 10, and 15 days. Additionally, primers, designed to a ∼300 bp domain conserved in bacterial and plant amidohydrolases, were used to amplify a product from seven members of the Brassicaceae family (A. suecica, A. pumila, A. himalaica, A. griffithiana, A. wallichii, Draba nemoroza and Capsella bursa-pastoris), Lycopersicon esculentum, and two monocot species (Zea mays and Allium cepa) using PCR; this result suggests similar genes may be characterized in other species.