Identification of oxidative stress-responsive C2H2 zinc fingers associated with Al tolerance in near-isogenic wheat lines

Al tolerance is one of the most important trait for worldwide crop production. Using microarrays, we previously identified a transcription factor belonging to the C2H2 zinc finger protein (ZFP) family associated with Al tolerance in wheat (Houde and Diallo, BMC Genomics 9:400, 2008). The current work aimed to identify specific members of the C2H2 ZFP family that are associated with Al tolerance. Wheat ESTs were used to assemble C2H2 ZFP family members that do not contain a classical EAR repressor domain. Specific primers were designed for qRT-PCR expression profiling of wheat root tips exposed to Al and H2O2. Two Al-tolerant and sensitive wheat cultivars including a pair of near-isogenic lines differing in Al tolerance were used. We reconstituted 16 wheat Q-type C2H2 ZFP. Expression profiling identified two transcripts (TaZFP2 and TaZFP3) that accumulate rapidly upon exposure to Al or in response to H2O2 in two tolerant wheat cultivars, including the tolerant near-isogenic line. The responsiveness of these transcripts to H2O2 suggests that they may represent the wheat orthologs of ZFP transcription factors ZAT7 and ZAT12 that were shown to improve ROS tolerance in Arabidopsis. Thus, they may play a crucial role in the improvement of oxidative stress tolerance in wheat.