For overexpression, ABA2 (GIN1) full-length cDNA was amplified by RT-PCR and cloned into pGEM-T Easy vector (Promega), followed by subcloning into the binary vector (pSMAB704) driven by a constitutive 35S promoter (35SABA2). For tissue-specific expression and GUS assay, the ABA2 promoter, approximately 2.9 kb upstream of the ATG start codon, was amplified by PCR and fused to a GUS coding region to generate ABA2GUS in the pSMAB704 binary vector. Transgene constructs were confirmed by sequencing and subsequently transformed into wild type or the aba2 mutant (T0) by use of the floral-dip method (Clough and Bent, 1998). T1 seeds with cold pretreatment were screened on 1% Suc agar plates containing 25 mg/L herbicide, glufosinate ammonium. At least 10 homozygous lines resistant to herbicide were obtained at the T3 or T4 generation. Three homozygous lines were randomly chosen for further study.