Yang Shuang, Lovelace Amelia H, Yuan Yi, Nie Haizhen, Chen Weikai, Gao Yi, Bo Wenhao, Nagel Dawn H, Pang Xiaoming, Ma Wenbo
State Key Laboratory of Tree Genetics and Breeding, National Engineering Research Center of Tree Breeding and Ecological Restoration, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants, Ministry of Education, College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, 100083, China.
The Sainsbury Laboratory, Norwich Research Park, Norwich, NR4 7UH, UK.
New Phytol. 2025 Jul;247(1):249-264. doi: 10.1111/nph.70172. Epub 2025 May 9.
Phytoplasmas are specialized phloem-limited bacteria that cause diseases on various crops, resulting in significant agricultural losses. This research focuses on the jujube witches' broom (JWB) phytoplasma and investigates the host-manipulating activity of the effector SJP39. We found that SJP39 directly interacts with the plant transcription factor bHLH87 in the nuclei. SJP39 stabilizes the bHLH87 homologs in Arabidopsis thaliana and jujube, leading to growth defects in the plants. Transcriptomic analysis indicates that SJP39 affects the gibberellin (GA) pathway in jujube. We further demonstrate that ZjbHLH87 regulates GA signaling as a negative regulator, and SJP39 enhances this regulation. The research offers important insights into the pathogenesis of JWB disease and identified SJP39 as a virulence factor that can contribute to the growth defects caused by JWB phytoplasma infection. These findings open new opportunities to manage JWB and other phytoplasma diseases.
植原体是一类专门寄生于韧皮部的细菌，可导致多种作物患病，造成重大农业损失。本研究聚焦于枣疯病植原体，并对效应蛋白SJP39的宿主操控活性进行了研究。我们发现SJP39在细胞核中直接与植物转录因子bHLH87相互作用。SJP39可稳定拟南芥和枣中bHLH87的同源物，导致植物生长缺陷。转录组分析表明，SJP39影响枣中的赤霉素（GA）途径。我们进一步证明，ZjbHLH87作为负调控因子调节GA信号传导，而SJP39增强了这种调控。该研究为枣疯病的发病机制提供了重要见解，并确定SJP39是一种毒力因子，可导致枣疯病植原体感染引起的生长缺陷。这些发现为防治枣疯病和其他植原体病害带来了新机遇。
