Guangdong Province Key Laboratory of Microbial Signals and Disease Control, South China Agricultural University, Guangzhou 510642, China.
San Joaquin Valley Agricultural Sciences Center, Agricultural Research Service, United States Department of Agriculture, Parlier, CA 90089, USA.
Int J Mol Sci. 2022 Sep 2;23(17):10024. doi: 10.3390/ijms231710024.
" Liberibacter asiaticus" (CLas) is the causal agent of citrus Huanglongbing (HLB, also called citrus greening disease), a highly destructive disease threatening citrus production worldwide. A novel phage (named CLasMV1) has been found to infect CLas, providing a potential therapeutic strategy for CLas/HLB control. However, little is known about the CLasMV1 biology. In this study, we analyzed the population dynamics of CLasMV1 between the insect vector of CLas, the Asian citrus psyllid (ACP, Kuwayama) and the holoparasitic dodder plant ( Yunck.); both acquired CLasMV1-infected CLas from an HLB citrus. All CLas-positive dodder samples were CLasMV1-positive, whereas only 32% of CLas-positive ACP samples were identified as CLasMV1-positive. Quantitative analyses showed a similar distribution pattern of CLasMV1 phage and CLas among eight citrus cultivars by presenting at highest abundance in the fruit pith and/or the center axis of the fruit. Transcriptome analyses revealed the possible lytic activity of CLasMV1 on CLas in fruit pith as evidenced by high-level expressions of CLasMV1 genes, and CLas genes related to cell wall biogenesis and remodeling to maintain the CLas cell envelope integrity. The up-regulation of CLas genes were involved in restriction-modification system that could involve possible phage resistance for CLas during CLasMV1 infection. In addition, the regulation of CLas genes involved in cell surface components and Sec pathway by CLasMV1 phage could be beneficial for phage infection. This study expanded our knowledge of CLasMV1 phage that will benefit further CLas phage research and HLB control.
“亚洲韧皮杆菌”（CLas）是柑橘黄龙病（HLB，也称为柑橘绿病）的病原体，这是一种对全球柑橘生产具有高度破坏性的疾病。已经发现一种新型噬菌体（命名为CLasMV1）感染 CLas，为 CLas/HLB 控制提供了一种潜在的治疗策略。然而，对于 CLasMV1 的生物学特性了解甚少。在这项研究中，我们分析了 CLas 的昆虫载体亚洲柑橘木虱（ACP，Kuwayama）和全寄生菟丝子之间 CLasMV1 的种群动态；两者均从 HLB 柑橘中获得了感染 CLasMV1 的 CLas。所有 CLas 阳性菟丝子样本均为 CLasMV1 阳性，而只有 32%的 CLas 阳性 ACP 样本被鉴定为 CLasMV1 阳性。定量分析表明，CLasMV1 噬菌体和 CLas 在八种柑橘品种中的分布模式相似，在果实髓心和/或果实中心轴中丰度最高。转录组分析表明，CLasMV1 在果实髓心中对 CLas 可能具有裂解活性，这表现为 CLasMV1 基因和与细胞壁生物发生和重塑相关的 CLas 基因的高水平表达，以维持 CLas 细胞包膜的完整性。CLas 基因的上调涉及限制修饰系统，这可能涉及 CLas 在 CLasMV1 感染期间对噬菌体的抗性。此外，CLasMV1 噬菌体对 CLas 基因的调节涉及细胞表面成分和 Sec 途径，这可能有利于噬菌体感染。本研究扩展了我们对 CLasMV1 噬菌体的认识，这将有助于进一步研究 CLas 噬菌体和 HLB 控制。
