Shi Yifeng, Bao Xiyue, Li Hai, Li Yuxiang, Chen Xianming, Hu Xiaoping
State Key Laboratory of Crop Stress Resistance and High-Efficiency Production, Key Laboratory of Plant Protection Resources and Pest Integrated Management of Ministry of Education, Key Laboratory of Integrated Pest Management on Crops in Northwestern Loess Plateau of Ministry of Agriculture and Rural Affairs, and College of Plant Protection, Northwest A&F University, Yangling, China.
State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
Mol Plant Pathol. 2025 Aug;26(8):e70132. doi: 10.1111/mpp.70132.
As the largest subfamily of small GTPases, the Rab subfamily plays a pivotal role in regulating biotic and abiotic stresses in plants. However, the functions of Rabs in resistance to wheat stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) remain unclear. Here, we identified a Rab subfamily gene, TaRABH1bL, from Xiaoyan 6 (XY6), a wheat cultivar known for non-race-specific and durable high-temperature all-stage (HTAS) resistance to stripe rust. The expression level of TaRABH1bL was exclusively up-regulated with Pst inoculation under the relatively high-temperature treatment, which indicated that TaRABH1bL might concurrently respond to both biotic and abiotic stress signals. The TaRABH1bL gene was primarily expressed in leaves. Barley stripe mosaic virus (BSMV)-induced TaRABH1bL gene silencing significantly reduced HTAS resistance to Pst, resulting in increased sporulation. Transient expression of TaRABH1bL in Nicotiana benthamiana leaves and wheat protoplasts confirmed its subcellular localisation in both cytoplasm and nuclei. The GTP-binding state of TaRABH1bL (TaRABH1bL) exclusively interacted with the transcription factor ethylene-responsive transcription factor 1-like (TaERF1L) in nuclei. TaERF1L directly bound to and suppressed the activity of the GCC-box motif, and this inhibitory effect was enhanced by the exclusive interaction between TaRABH1bL and TaERF1L. Silencing TaERF1L significantly reduced HTAS resistance. These results suggested that under dual signals of Pst infection and relatively high temperature treatment, TaRABH1bL transferred into its GTP-binding state and interacted with TaERF1L. Additionally, TaRABH1bL enhanced the suppression of TaERF1L on its downstream susceptible or temperature-sensitive genes containing the GCC-box motif, thereby activating HTAS resistance to Pst in XY6.
作为小GTP酶的最大亚家族，Rab亚家族在调节植物的生物和非生物胁迫中起关键作用。然而，Rab蛋白在小麦对条锈菌（Puccinia striiformis f. sp. tritici，Pst）引起的条锈病抗性中的功能仍不清楚。在此，我们从小偃6号（XY6）中鉴定出一个Rab亚家族基因TaRABH1bL，小偃6号是一个以对条锈病具有非小种特异性和持久的高温全生育期（HTAS）抗性而闻名的小麦品种。在相对高温处理下，接种Pst后TaRABH1bL的表达水平仅上调，这表明TaRABH1bL可能同时响应生物和非生物胁迫信号。TaRABH1bL基因主要在叶片中表达。大麦条纹花叶病毒（BSMV）诱导的TaRABH1bL基因沉默显著降低了对Pst的HTAS抗性，导致产孢增加。TaRABH1bL在本氏烟草叶片和小麦原生质体中的瞬时表达证实了其在细胞质和细胞核中的亚细胞定位。TaRABH1bL的GTP结合状态仅在细胞核中与转录因子乙烯响应转录因子1样（TaERF1L）相互作用。TaERF1L直接结合并抑制GCC-box基序的活性，并且TaRABH1bL与TaERF1L之间的特异性相互作用增强了这种抑制作用。沉默TaERF1L显著降低了HTAS抗性。这些结果表明，在Pst感染和相对高温处理的双重信号下，TaRABH1bL转变为其GTP结合状态并与TaERF1L相互作用。此外，TaRABH1bL增强了TaERF1L对其含有GCC-box基序的下游易感或温度敏感基因的抑制作用，从而激活了XY6对Pst的HTAS抗性。
