National Citrus Engineering Research Center, Citrus Research Institute, Southwest University, Chongqing 400712, China.
Department of Plant Protection, Faculty of Agricultural Sciences, Ghazi University, Dera Ghazi Khan 32200, Pakistan.
Phytopathology. 2021 May;111(5):784-788. doi: 10.1094/PHYTO-10-20-0454-SC. Epub 2021 Apr 1.
' Liberibacter asiaticus' (CLas) is a pathogen causing Huanglongbing (HLB, yellow shoot disease), which is highly destructive to citrus production. The CLas strains harbor prophages. We identified two unique prophages, designated as P-PA19-1 and P-PA19-2, in CLas strain PA19 from Pakistan using next-generation sequencing analysis. P-PA19-1 prophage has high sequence similarity (identity: 78.23%) at the early-gene region of prophage SC1 (Type 1), but it is significantly divergent in the late-gene region (identity: 62.03%). P-PA19-2 was highly similar to SC2 (Type 2) in the late gene region (identity: 97.96%), and also in the early gene region except for a deletion of a 7,179-bp nucleotide sequence that contains a CRISPR/cas system in SC2. Both P-PA19-1 and P-PA19-2 had circular plasmid forms, and only P-PA19-2 was found integrated in the PA19 chromosome. The two new prophages were only found in Pakistani samples. Identification of prophages enhances our understanding of CLas genomic diversity and also the biology and evolution of CLas prophages.
“亚洲韧皮杆菌”（CLas）是一种引起黄龙病（HLB，黄梢病）的病原体，对柑橘生产具有高度破坏性。CLas 菌株携带原噬菌体。我们使用下一代测序分析在巴基斯坦的 CLas 菌株 PA19 中鉴定了两个独特的原噬菌体，分别命名为 P-PA19-1 和 P-PA19-2。P-PA19-1 原噬菌体在早期基因区域与原噬菌体 SC1（Type 1）具有高度相似性（同一性：78.23%），但在晚期基因区域差异显著（同一性：62.03%）。P-PA19-2 在晚期基因区域（同一性：97.96%）与 SC2（Type 2）高度相似，除了在 SC2 中包含 CRISPR/cas 系统的 7179bp 核苷酸序列缺失外，在早期基因区域也相似。P-PA19-1 和 P-PA19-2 都具有环状质粒形式，只有 P-PA19-2 被发现整合在 PA19 染色体中。这两个新的原噬菌体仅在巴基斯坦样本中发现。原噬菌体的鉴定增强了我们对 CLas 基因组多样性以及 CLas 原噬菌体的生物学和进化的理解。
