Preventing pathological expansion of tandem repeats
Analysis of the FGF14-SCA27B repeat locus identifies a common 5'-flanking insertion that is present exclusively in non-pathogenic alleles and enhances repeat stability.
新植物学家：西北农林发现一个参与小麦抗病的NAC转录因子
小麦的生长发育受到真菌病害Blumeria graminis f. sp. tritici (Bgt)的影响。本研究发现了一个来自小麦的 transcription factor-TaNAC1, 参与了对该病害的响应过程。
首先该转录因子S184/S258位点受到TaCDPK20的磷酸化修饰，促进了它向细胞核的转运，这会进一步促进它被 TaMPK1的磷酸化, 从而提高了该转录因子对靶基因的表达调控能力。
于此同时一个蛋白磷酸酶PP2Ac则负调控该转录因子的磷酸化水平。TaNAC1的磷酸化导致它对下游靶基因TaSec1a and TaCAMTA4的诱导, 这依赖于该转录因子结合C[T/G]T[N7]A[A/C]G 顺式作用元件. 表型分析显示，抑制TaNAC1, TaCDPK20, and TaMPK1均会导致小麦对病害的抗性下降，而过表达株系的抗性则显著提高。
小结：本研究揭示了来自小麦的转录因子TaNAC1提高小麦抗病能力的机制。
Proposed model for the role of the TaCDPK20, TaMPK1, TaPP2Ac, TaNAC1, and TaSec1a/TaCAMTA4 cascade in regulating cell death and resistance against Bgt. Blumeria graminis is a damaging fungal pathogen that causes powdery mildew in wheat. Upon infection, the host activates both CDPK and MAPK signal-related kinases. TaCDPK20, a calcium-dependent protein kinase, interacts with the transcription factor TaNAC1 in the cytoplasm, enhancing its phosphorylation. This modification facilitates TaNAC1’s rapid nuclear translocation where further phosphorylation by MPK1 or dephosphorylation by PP2Ac occur. The phosphorylated NAC1 then binds to the promoters of TaSec1a and TaCAMTA4, upregulating their expression, which has been demonstrated to confer increased resistance to powdery mildew pathogens through inoculation trials. Question mark means that the detailed protein in wheat is still unknown. The dashed arrow means the associated evidence is based on the literatures referencing other species. The blunt arrow represents the repressive activity.
原文：TaNAC1 boosts powdery mildew resistance by phosphorylation-dependent regulation of TaSec1a and TaCAMTA4 via PP2Ac/CDPK20
