Huanglongbing (HLB) is the most devastating citrus disease in the world. Almost all commercial citrus varieties are susceptible to the causal bacterium, Candidatus Liberibacter asiaticus (CLas), which is transmitted by the Asian citrus psyllid (ACP). Currently, there are no effective management strategies to control HLB. HLB‐tolerant traits have been reported in some citrus relatives and citrus hybrids, which offer a direct pathway for discovering natural defence regulators to combat HLB. Through comparative analysis of small RNA profiles and target gene expression between an HLB‐tolerant citrus hybrid (Poncirus trifoliata × Citrus reticulata) and a susceptible citrus variety, we identified a panel of candidate defence regulators for HLB‐tolerance. These regulators display similar expression patterns in another HLB‐tolerant citrus relative, with a distinct genetic and geographic background, the Sydney hybrid (Microcitrus virgata). Because the functional validation of candidate regulators in tree crops is always challenging, we developed a novel rapid functional screening method, using a C. Liberibacter solanacearum (CLso)/potato psyllid/Nicotiana benthamiana interaction system to mimic the natural transmission and infection circuit of the HLB complex. When combined with efficient virus‐induced gene silencing in N. benthamiana, this innovative and cost‐effective screening method allows for rapid identification and functional characterization of regulators involved in plant immune responses against HLB, such as the positive regulator BRCA1‐Associated Protein, and the negative regulator Vascular Associated Death Protein.

中文翻译：

---

使用新的功能筛选系统鉴定参与黄龙病防御的柑橘免疫调节剂


黄龙病（HLB）是世界上最具破坏性的柑橘病害。几乎所有商业柑橘品种都对致病细菌亚洲自由杆菌 ( C Las)敏感，该细菌由亚洲柑橘木虱 (ACP) 传播。目前，尚无有效的管理策略来控制HLB。据报道，一些柑橘近缘种和柑橘杂交品种具有 HLB 耐受性特征，这为发现对抗 HLB 的自然防御调节剂提供了直接途径。通过对 HLB 耐受柑橘杂交种（枳×柑橘）和易感柑橘品种之间的小 RNA 谱和靶基因表达进行比较分析，我们确定了一组 HLB 耐受的候选防御调节因子。这些调节因子在另一种具有独特遗传和地理背景的耐 HLB 柑橘近缘品种——悉尼杂交种（ Microcitrus virgata ）中表现出相似的表达模式。由于木本作物中候选调节剂的功能验证始终具有挑战性，因此我们开发了一种新颖的快速功能筛选方法，使用C 。青枯菌 ( C Lso ) /马铃薯木虱/本塞姆氏烟草相互作用系统模拟 HLB 复合体的自然传播和感染回路。当与N中有效的病毒诱导基因沉默相结合时。 Benthamiana是一种创新且经济高效的筛选方法，可以快速识别和功能表征参与针对 HLB 的植物免疫反应的调节因子，例如正调节因子 BRCA1 相关蛋白和负调节因子血管相关死亡蛋白。