TaqMan qRT-PCR Assay for Detecting Bovine Kobuvirus
-
摘要:
目的 建立一种快速、准确且能定量分析牛嵴病毒(Bovine kobuvirus,BKoV)的检测方法。 方法 根据GenBank上发布的牛嵴病毒3D基因序列设计合成一对特异性引物和一条探针,通过优化反应体系建立牛嵴病毒TaqMan荧光定量RT-PCR检测方法,并对临床样品进行检测。 结果 该方法最佳上下游引物浓度均为300 nmol·L−1,探针浓度为400 nmol·L−1,在1×101~1×108 copies·µL−1呈现良好的线性关系,线性相关系数R2=0.999,扩增效率为103%;特异性较强,在多个犊牛腹泻相关病原中,只检测出牛嵴病毒;敏感性较高,对BKoV质粒标准品最低检测下限为1×101 copies·µL−1,而普通RT-PCR对BKoV质粒标准品最低检测下限为1×102 copies·µL−1;重复性较好,组内变异系数和组间变异系数均小于3%。2021年3~5月采自内蒙古地区牧场的37份犊牛粪样中BKoV的检出率为24.3%,通过标准曲线计算其病毒载量,其中腹泻粪样平均病毒载量为3.7×105 copies·µL−1,健康犊牛粪样平均病毒载量为8.65×103 copies·µL−1。 结论 建立的牛嵴病毒TaqMan荧光定量RT-PCR检测方法特异性强、稳定性好、灵敏度高,为BKoV的检测和分子流行病学调查提供了有力的手段。 Abstract:Objective A rapid, accurate qRT-PCR method for detecting bovine kobuvirus (BKoV) was established and clinically tested for application. Method A pair of specific primers and a probe were designed and synthesized according to the 3D gene sequence of BKoV published on GenBank for the establishment of a TaqMan fluorescence qRT-PCR assay. The reaction system of the analytic was optimized prior to verification on clinical specimens. Result The optimal upstream and downstream primers were 300 nmol·L−1 in concentration, and the applied probe 400 nmol·L−1. A linearity with a correlation coefficient of R2= 0.999 was achieved in the range of 1×101−1×108 copies·μL−1. The amplification efficiency reached 103%. The assay demonstrated a high specificity among the pathogens related to diarrhea in calves, a high sensitivity with the minimum detection limit of 1×101 copies·μL−1 on BKoV plasmid standard, in comparison to that of 1×102 copies·μL−1 by conventional RT-PCR, and a high repeatability with a coefficient of variation of less than 3% within and between groups. In 37 bovine fecal samples collected from different pastures in Inner Mongolia from March to May 2021, the assay showed a positive detection rate of 24.3%. The calculated viral loads using the standard curve had an average on the feces from diarrheal animals at 3.7×105 copies·μL−1 and at 8.65×103 copies·μL−1 on the specimens from healthy calves. Conclusion The newly developed TaqMan fluorescent qRT-PCR assay was specific, repeatable, and sensitive in detecting BKoV. It could be applied for clinic diagnosis and epidemiological investigation on the disease. -
Key words:
- Bovine kobuvirus /
- fluorescence qRT-PCR /
- calf diarrhea /
- specificity /
- sensitivity /
- repeatability
-
表 1 牛嵴病毒引物及探针序列信息
Table 1. Sequences of BKoV primers and probe
项目
Items名称
Names序列(5'-3')
Sequences(5'-3')扩增长度
Amplification length/bp引物 Primers BKoV-F-221 TYTCACCYGCTTGGCTCTC 200 S-BKoV-R-421 AGTGTAGGTGCCRCGCAT+A 探针 Probe BKV-TZ FAM-CTTCACACAGTGGCGTGGTGAACT-BHQ1 表 2 牛嵴病毒荧光定量RT-PCR组内及组间重复性
Table 2. Intra- and inter-group repeatability of qRT-PCR assay for BKoV detection
标准品
Plasmid standard
concentration/
(copies·µL−1)组内重复性
Reproducibility intra-group组间重复性
Reproducibility intra-group平均值
(M±SD)/%变异系数
CV/%平均值
(M±SD)/%变异系数
CV/%1×106 21.99±0.23 1.0 22.02±0.04 0.2 1×105 25.30±0.03 0.1 25.31±0.09 0.4 1×104 28.76±0.24 0.8 28.91±0.13 0.4 1×103 32.04±0.03 0.1 32.19±0.29 0.9 1×102 34.82±0.49 1.4 34.77±0.63 1.8 表 3 犊牛粪样牛嵴病毒载量检测
Table 3. Detection of BKoV load on calf fecal samples
粪样
Fecal samples数量
Number阳性数量
Positive
number最低拷贝数
Minimum copies/
(copies·µL−1)最高拷贝数
Maximum copies/
(copies·µL−1)平均拷贝数
Average copies/
(copies·µL−1)腹泻
Diarrhea30 7 2.33×103 1.90×106 3.70×105 健康
Healthy7 2 3.54×103 1.38×103 8.65×103 -
[1] MOHAMED F F, MANSOUR S M G, ORABI A, et al. Detection and genetic characterization of bovine kobuvirus from calves in Egypt [J]. Archives of Virology, 2018, 163(6): 1439−1447. doi: 10.1007/s00705-018-3758-1 [2] 师志海, 王文佳, 王亚州, 等. 染料法实时荧光PCR检测牛嵴病毒 [J]. 中国兽医科学, 2021, 51(12):1498−1503. doi: 10.16656/j.issn.1673-4696.2021.0210SHI Z H, WANG W J, WANG Y Z, et al. A real-time PCR suitable for detection of bovine kobuvirus based on the fluorescent dye [J]. Chinese Veterinary Science, 2021, 51(12): 1498−1503.(in Chinese) doi: 10.16656/j.issn.1673-4696.2021.0210 [3] REUTER G, BOROS A, PANKOVICS P. Kobuviruses - a comprehensive review [J]. Reviews in Medical Virology, 2011, 21(1): 32−41. doi: 10.1002/rmv.677 [4] HAO L L, CHEN C X, BAILEY K, et al. Bovine kobuvirus-a comprehensive review [J]. Transboundary and Emerging Diseases, 2021, 68(4): 1886−1894. doi: 10.1111/tbed.13909 [5] 杨振, 张笛, 于恩琪, 等. 江苏省七个县域猪嵴病毒感染的流行病学调查 [J]. 中国兽医科学, 2014, 44(4):436−440. doi: 10.16656/j.issn.1673-4696.2014.04.012YANG Z, ZHANG D, YU E Q, et al. Epidemiological investigation of porcine kobuvirus infection in 7 counties of Jiangsu Province [J]. Chinese Veterinary Science, 2014, 44(4): 436−440.(in Chinese) doi: 10.16656/j.issn.1673-4696.2014.04.012 [6] 王文佳, 徐照学, 兰亚莉, 等. 牛冠状病毒、牛诺如病毒和牛嵴病毒多重PCR检测方法的建立及初步应用 [J]. 中国兽医学报, 2020, 40(7):1306−1310,1355.WANG W J, XU Z X, LAN Y L, et al. Establishment and preliminary application of a multiple PCR for detection of BCoV, BNoV and BKV [J]. Chinese Journal of Veterinary Science, 2020, 40(7): 1306−1310,1355.(in Chinese) [7] 师志海, 王文佳, 孟红丽, 等. 荧光探针PCR检测牛嵴病毒的方法建立 [J]. 中国兽医学报, 2022, 42(4):657−661.SHI Z H, WANG W J, MENG H L, et al. Establishment of a TaqMan PCR assay for detecting bovine kobuvirus [J]. Chinese Journal of Veterinary Science, 2022, 42(4): 657−661.(in Chinese) [8] 彭雪松. BVDV基因分型检测方法的建立及应用[D]. 呼和浩特: 内蒙古农业大学, 2021.PENG X S. Establishment and application of detection method for BVDV genotyping[D]. Hohhot: Inner Mongolia Agricultural University, 2021. (in Chinese) [9] 赵润涛, 王旭芬, 侯琳, 等. 牛纽布病毒TaqMan荧光定量RT-PCR检测方法的建立及应用 [J]. 中国兽医学报, 2023, 43(1):66−71. doi: 10.16303/j.cnki.1005-4545.2023.01.11ZHAO R T, WANG X F, HOU L, et al. Establishment and application of TaqMan real-time quantitative RT-PCR for detection of bovine nebovirus [J]. Chinese Journal of Veterinary Science, 2023, 43(1): 66−71.(in Chinese) doi: 10.16303/j.cnki.1005-4545.2023.01.11 [10] 闫琛博, 李振亚, 吕海淼, 等. 河南省犊牛腹泻主要病原调查研究 [J]. 中国牛业科学, 2020, 46(5):44−48. doi: 10.3969/j.issn.1001-9111.2020.05.013YAN C B, LI Z Y, LV H M, et al. Investigation on the main pathogens of calf diarrhea in Henan Province [J]. China Cattle Science, 2020, 46(5): 44−48.(in Chinese) doi: 10.3969/j.issn.1001-9111.2020.05.013 [11] 王艾梅. 规模化牛场犊牛腹泻的原因及治疗方法 [J]. 畜禽业, 2022, 33(2):117−118. doi: 10.19567/j.cnki.1008-0414.2022.02.047WANG A M. Causes and treatment of calf diarrhea in large-scale cattle farm [J]. Livestock and Poultry Industry, 2022, 33(2): 117−118.(in Chinese) doi: 10.19567/j.cnki.1008-0414.2022.02.047 [12] 荔霞, 王胜义, 刘永明, 等. 犊牛腹泻病因及其药物防治研究进展 [J]. 中国畜牧兽医, 2010, 37(10):161−165.LI X, WANG S Y, LIU Y M, et al. Progress of calf diarrhea causes and prevention of drug [J]. China Animal Husbandry & Veterinary Medicine, 2010, 37(10): 161−165.(in Chinese) [13] MAUROY A, SCIPIONI A, MATHIJS E, et al. Molecular detection of kobuviruses and recombinant noroviruses in cattle in continental Europe [J]. Archives of Virology, 2009, 154(11): 1841−1845. doi: 10.1007/s00705-009-0518-2 [14] CHANG J T, WANG Q, WANG F, et al. Prevalence and genetic diversity of bovine kobuvirus in China [J]. Archives of Virology, 2014, 159(6): 1505−1510. doi: 10.1007/s00705-013-1961-7 [15] 刘彩娟, 罗清华, 李威. 牛病毒性腹泻病在养牛生产中的研究进展 [J]. 饲料广角, 2012(23):38−40. doi: 10.3969/j.issn.1002-8358.2012.23.037LIU C J, LUO Q H, LI W. Research progress of bovine viral diarrhea in cattle production [J]. Feed China, 2012(23): 38−40.(in Chinese) doi: 10.3969/j.issn.1002-8358.2012.23.037 [16] 李生茂, 徐祥, 梁华平, 等. 锁核酸研究进展 [J]. 生理科学进展, 2003, 34(4):319−323.LI S M, XU X, LIANG H P, et al. Progress in locked nucleic acid research [J]. Progress in Physiological Sciences, 2003, 34(4): 319−323.(in Chinese)