State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China.
State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing 100193, China.
Plant Cell. 2022 Jul 30;34(8):2833-2851. doi: 10.1093/plcell/koac137.
Maize (Zea mays) originated in tropical areas and is thus susceptible to low temperatures, which pose a major threat to maize production. Our understanding of the molecular basis of cold tolerance in maize is limited. Here, we identified bZIP68, a basic leucine zipper (bZIP) transcription factor, as a negative regulator of cold tolerance in maize. Transcriptome analysis revealed that bZIP68 represses the cold-induced expression of DREB1 transcription factor genes. The stability and transcriptional activity of bZIP68 are controlled by its phosphorylation at the conserved Ser250 residue under cold stress. Furthermore, we demonstrated that the bZIP68 locus was a target of selection during early domestication. A 358-bp insertion/deletion (Indel-972) polymorphism in the bZIP68 promoter has a significant effect on the differential expression of bZIP68 between maize and its wild ancestor teosinte. This study thus uncovers an evolutionary cis-regulatory variant that could be used to improve cold tolerance in maize.
玉米（Zea mays）起源于热带地区，因此对低温敏感，这对玉米生产构成了重大威胁。我们对玉米耐寒性的分子基础的了解有限。在这里，我们鉴定了 bZIP68，一种碱性亮氨酸拉链（bZIP）转录因子，作为玉米耐寒性的负调控因子。转录组分析表明，bZIP68 抑制 DREB1 转录因子基因的冷诱导表达。bZIP68 的稳定性和转录活性受其在冷胁迫下保守丝氨酸 250 残基的磷酸化控制。此外，我们证明 bZIP68 基因座是早期驯化过程中选择的靶标。bZIP68 启动子中的 358-bp 插入/缺失（Indel-972）多态性对玉米与其野生祖先大刍草之间 bZIP68 的差异表达有显著影响。因此，这项研究揭示了一个进化上的顺式调控变异，可以用来提高玉米的耐寒性。
