Understanding Bacterial Virulence Genes and Mechanisms of Host Response to Insect-Mediated Citrus Huanglongbing

探討昆蟲媒介傳播之柑橘黃龍病細菌致病基因與其寄主反應機制

林宏(Hong Lin)

《植物病理學會刊》 22卷4期 (2013/12) Pp. 309-325

https://doi.org/10.6649/PPB.201312_22(4).0001

摘要

這篇論說主要以基因體學及蛋白質體學方法探討對柑橘產業具毀滅性之柑橘黃龍病病原菌與寄主之分子交互作用。柑橘黃龍病在美國與其他種植柑橘的地區均可造成極大的威脅。此病害發生與一群革蘭氏陰性、寄生於植物韌皮部、可藉由昆蟲傳播且無法人工培養的原核生物：”Candidatus Liberibacter spp.”有密切關聯。Candidatuls Liberibacter spp.的分類地位屬於α-變型菌綱（α-Proteobacteria）、根瘤菌科（Rhizobiaceae）。即使此病害的柯霍式法則尚未完成，但隨著黃龍病菌基因體序列之完成與發表，有關柑橘黃龍病的分子病理學研究已有相當的進展。而分析與註解其基因體序列中所轉譯之基因產物則使我們進一步了解柑橘黃龍病菌致病力之遺傳特性與其生理和代謝的能力。若能鑑別此病原菌之重要致病基因與確定其功能，研究人員即可以此致病基因為主要對象，設計與開發出新的防治方法。又因目前大部分栽培的商業用柑桔品系對黃龍病均感病，故了解寄主植物受到黃龍病菌感染時之的分子反應機制便成為未來開發柑橘黃龍病抗病品系與其應用的關鍵。而未來可長期且有效防治柑橘黃龍病的方法應為移除或減少媒介昆蟲與感染源及提升寄主對黃龍病菌及木蝨的抗性之綜合栽培管理策略。

關鍵字

黃龍病 ； 蛋白質體學 ； 致病基因 ； 寄主反應

並列摘要

A summary is provided for research progress in studying genomics and proteomics of molecular pathogen-host interactions for citrus huanglongbing (HLB), a destructive disease of citrus that presents a major threat to the citrus industries in US as well as other citrus production regions in the world. The disease is associated with a gram-negative, phloem-limited, insect-vectored, unculturable prokaryote: 'Candidatus Liberibacter spp', that belong to the Rhizobiaceae family of α-Proteobacteria. Despite the fact that Koch's postulates have not been fulfilled, a considerable progress has been made in understanding molecular basis of HLB disease since the publication of HLB-associated Liberibacter genome. Annotation of the Liberibacter genome sequence has provided insights into the genetic basis of the virulence, physiological and metabolic capabilities of this organism. Functional determination of key virulence genes will permit researchers to design and develop a novel gene-based therapeutic treatment to control the disease. Since most commercial citrus cultivars are susceptible to HLB, understanding the molecular mechanisms of host response is crucial for the development and deployment of HLB-resistant citrus varieties. A long term and sustainable management of HLB is likely to be based on integrated strategies including removal or reduction of vectors or inocula, and the improvement of host resistance to HLB-associated Liberibacters and psyllid vectors.

並列關鍵字

huanglongbing ； Candidatus Liberibacter asiaticus ； proteomics ； virulence genes ； host response