NAC (NAM, AFAT1/2, and CUC2) transcription factors play important roles in plant growth and in resistance to abiotic and biotic stresses. Here, we show that the TaNAC35 gene negatively regulates leaf rust resistance in the wheat line Thatcher + Lr14b (TcLr14b) when challenged with a virulent isolate of Puccinia triticina (Pt). The TaNAC35 gene was cloned from this line, and blastp results showed that its open reading frame (ORF) was 96.16% identical to the NAC35-like sequence reported from Aegilops tauschii, and that it encoded a protein with 387 amino acids (aa) including a conserved NAM domain with 145 aa at the N-terminal alongside the transcriptional activation domain with 220 aa in the C-terminal. Yeast-one-hybrid analysis proved that the C-terminal of the TaNAC35 protein was responsible for transcriptional activation. A 250-bp fragment from the 3′-end of this target gene was introduced to a BSMV-VIGS vector and used to infect the wheat line Thatcher + Lr14b (TcLr14b). The BSMV-VIGS/TaNAC35-infected plant material showed enhanced resistance (infection type “1”) to Pt pathotype THTT, which was fully virulent (infection type “4”) on BSMV-VIGS only infected TcLr14b plants. Histological studies showed that inhibition of TaNAC35 reduced the formation of haustorial mother cells (HMC) and mycelial growth, implying that the TaNAC35 gene plays a negative role in the response of TcLr14b to Pt pathotype THTT. These results provide molecular insight into the interaction between Pt and its wheat host, and identify a potential target for engineering resistance in wheat to this damaging pathogen.

NAC（NAM，AFAT1 / 2和CUC2）转录因子在植物生长以及对非生物和生物胁迫的抗性中起重要作用。在这里，我们显示，当用小麦锈菌（Puccinia triticina）（Pt）的有毒分离物攻击时，TaNAC35基因负调节小麦系Thatcher + Lr14b（TcLr14b）的叶片防锈能力。所述TaNAC35基因从该品系中克隆，和BLASTP结果表明，它的开放阅读框（ORF）是96.16％相同的NAC35样序列从报道节节麦，并且它编码具有387个氨基酸（aa）的蛋白质，其中包括一个保守的NAM域（在N端具有145个氨基酸）和转录激活域（在C端具有220个氨基酸）。酵母一杂交分析证明TaNAC35蛋白的C端负责转录激活。将来自该靶基因3'端的250bp片段引入到BSMV-VIGS载体中，并用于感染小麦系撒切尔+ Lr14b（TcLr14b）。感染了BSMV-VIGS / TaNAC35的植物材料显示出对Pt病原体THTT的抗性增强（感染类型“ 1”），在仅感染了BSMV-VIGS的TcLr14b植物上具有完全毒性（感染类型“ 4”）。组织学研究表明抑制TaNAC35减少了子宫肌母细胞（HMC）的形成和菌丝体的生长，这暗示TaNAC35基因在TcLr14b对Pt病态THTT的应答中起负作用。这些结果提供了对Pt及其小麦宿主之间相互作用的分子了解，并确定了小麦对这种有害病原体的工程抗性的潜在目标。