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Li J, Gao H, Li Y, Zhai S, Xiao F, Wu G, Wu Y. The Development of a Series of Genomic DNA Reference Materials with Specific Copy Number Ratios for The Detection of Genetically Modified Maize DBN9936. Foods 2024; 13:747. [PMID: 38472860 DOI: 10.3390/foods13050747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/18/2024] [Accepted: 02/22/2024] [Indexed: 03/14/2024] Open
Abstract
The genetically modified (GM) maize DBN9936 with a biosafety certificate will soon undergo commercial application. To monitor the safety of DBN9936 maize, three genomic DNA (gDNA) reference materials (RMs) (DBN9936a, DBN9936b, and DBN9936c) were prepared with nominal copy number ratios of 100%, 3%, and 1% for the DBN9936 event, respectively. DBN9936a was prepared from the leaf tissue gDNA of DBN9936 homozygotes, while DBN9936b and DBN9936c were prepared by the quantitative mixing of gDNA from the leaf tissues of DBN9936 homozygotes and non-GM counterparts. Validated DBN9936/zSSIIb duplex droplet digital PCR was demonstrated to be an accurate reference method for conducting homogeneity study, stability study, and collaborative characterization. The minimum intake for one measurement was determined to be 2 μL, and the gDNA RMs were stable during transport at 37 °C for 14 days and storage at -20 °C for 18 months. Each gDNA RM was certified for three property values: DBN9936 event copy number concentration, zSSIIb reference gene copy number concentration, and DBN9936/zSSIIb copy number ratio. The measurement uncertainty of the certified values took the uncertainty components related to possible inhomogeneity, instability, and characterization into account. This batch of gDNA RMs can be used for calibration and quality control when quantifying DBN9936 events.
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Affiliation(s)
- Jun Li
- Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Hongfei Gao
- Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Yunjing Li
- Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Shanshan Zhai
- Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Fang Xiao
- Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Gang Wu
- Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Yuhua Wu
- Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan 430062, China
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Dhar BC, Delgado Santander R, Aćimović SG. Improved Canker Processing and Viability Droplet Digital PCR Allow Detection of Erwinia amylovora Viable Nonculturable Cells in Apple Bark. Microorganisms 2024; 12:376. [PMID: 38399780 PMCID: PMC10893025 DOI: 10.3390/microorganisms12020376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024] Open
Abstract
The bacterium Erwinia amylovora causes fire blight and continues to threaten global commercial apple and pear production. Conventional microbiology techniques cannot accurately determine the presence of live pathogen cells in fire blight cankers. Several factors may prevent E. amylovora from growing on solid culture media, including competing microbiota and the release of bacterial-growth-inhibitory compounds by plant material during sample processing. We previously developed a canker processing methodology and a chip-based viability digital PCR (v-dPCR) assay using propidium monoazide (PMA) to bypass these obstacles. However, sample analysis was still time-consuming and physically demanding. In this work, we improved the previous protocol using an automatic tissue homogenizer and transferred the chip-based v-dPCR to the BioRad QX200 droplet dPCR (ddPCR) platform. The improved sample processing method allowed the simultaneous, fast, and effortless processing of up to six samples. Moreover, the transferred v-ddPCR protocol was compatible with the same PMA treatment and showed a similar dynamic range, from 7.2 × 102 to 7.6 × 107 cells mL-1, as the previous v-dPCR. Finally, the improved protocol allowed, for the first time, the detection of E. amylovora viable but nonculturable (VBNC) cells in cankers and bark tissues surrounding cankers. Our v-ddPCR assay will enable new ways to evaluate resistant pome fruit tree germplasm, further dissect the E. amylovora life cycle, and elucidate E. amylovora physiology, epidemiology, and new options for canker management.
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Affiliation(s)
- Bidhan Chandra Dhar
- Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Polytechnic Institute and State University, 595 Laurel Grove Rd, Winchester, VA 22602, USA;
| | - Ricardo Delgado Santander
- Irrigated Agriculture Research and Extension Center, College of Agricultural, Human and Natural Resource Sciences, Washington State University, Prosser, WA 99350, USA;
| | - Srđan G. Aćimović
- Alson H. Smith Jr. Agricultural Research and Extension Center, School of Plant and Environmental Sciences, Virginia Polytechnic Institute and State University, 595 Laurel Grove Rd, Winchester, VA 22602, USA;
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Hou Y, Chen S, Zheng Y, Zheng X, Lin JM. Droplet-based digital PCR (ddPCR) and its applications. Trends Analyt Chem 2022. [DOI: 10.1016/j.trac.2022.116897] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Xu W, Zhu P, Xin T, Lou Q, Li R, Fu W, Ma T, Song J. Droplet digital PCR for the identification of plant-derived adulterants in highly processed products. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2022; 105:154376. [PMID: 35963193 DOI: 10.1016/j.phymed.2022.154376] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 07/18/2022] [Accepted: 08/01/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND The high sensitivity of droplet digital PCR (ddPCR) contributes to its excellent performance in animal and microorganism identification, but the utilization of ddPCR is limited in plant adulterant identification of highly processed products for which effective methods are lacking. PURPOSE This study investigated the feasibility of ddPCR in the identification of plant adulterants in Chinese patent medicine (CPM) as groundwork to develop ddPCR assays for other highly processed goods. METHODS The original plant, processed and highly processed products of Mutong (Akebiae Caulis) and its two adulterants were used to analyze the specificity, sensitivity, and practical performance of the developed singleplex and triplex ddPCR assays. RESULTS The results revealed that the limit of detection (LOD) and limit of quantification (LOQ) for the selective ddPCR assays developed to identify Mutong and its adulterants were 0.00002 ng/μl and 0.00016 ng/μl, respectively, and that the regression equations representing the relationships between DNA concentration and target copy number all exhibited good linearity. Furthermore, the common adulterant of Mutong in three samples of Longdan Xiegan pills was successfully identified through ddPCR assays and confirmed by Sanger sequencing. CONCLUSION This work comprehensively revealed the great ability of ddPCR technology in detecting plant adulterants in traditional Chinese medicine (TCM), providing a method for the quality control of highly processed plant products with complex components for commonly used goods.
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Affiliation(s)
- Wenjie Xu
- Key Laboratory of Chinese Medicine Resources Conservation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China
| | - Pengyu Zhu
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Tianyi Xin
- Key Laboratory of Chinese Medicine Resources Conservation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China
| | - Qian Lou
- Key Laboratory of Chinese Medicine Resources Conservation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China
| | - Ranjun Li
- Key Laboratory of Chinese Medicine Resources Conservation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China
| | - Wei Fu
- Institute of Plant Quarantine, Chinese Academy of Inspection and Quarantine, Beijing 100176, China
| | - Tingyu Ma
- Key Laboratory of Chinese Medicine Resources Conservation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China
| | - Jingyuan Song
- Key Laboratory of Chinese Medicine Resources Conservation, State Administration of Traditional Chinese Medicine of the People's Republic of China, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100193, China; Engineering Research Center of Chinese Medicine Resource, Ministry of Education, Beijing 100193, China; Yunnan Key Laboratory of Southern Medicine Utilization, Yunnan Branch Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences, Jinghong 666100, China.
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Choi CH, Kim E, Yang SM, Kim DS, Suh SM, Lee GY, Kim HY. Comparison of Real-Time PCR and Droplet Digital PCR for the Quantitative Detection of Lactiplantibacillus plantarum subsp. plantarum. Foods 2022; 11:foods11091331. [PMID: 35564054 PMCID: PMC9105557 DOI: 10.3390/foods11091331] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/26/2022] [Accepted: 04/30/2022] [Indexed: 12/04/2022] Open
Abstract
Droplet digital polymerase chain reaction (ddPCR) is one of the newest and most promising tools providing absolute quantification of target DNA molecules. Despite its emerging applications in microorganisms, few studies reported its use for detecting lactic acid bacteria. This study evaluated the applicability of a ddPCR assay targeting molecular genes obtained from in silico analysis for detecting Lactiplantibacillus plantarum subsp. plantarum, a bacterium mainly used as a starter or responsible for fermentation in food. The performance characteristics of a ddPCR were compared to those of a quantitative real-time PCR (qPCR). To compare the linearity and sensitivity of a qPCR and ddPCR, the calibration curve for a qPCR and the regression curve for a ddPCR were obtained using genomic DNA [102−108 colony-forming units (CFU)/mL] extracted from a pure culture and spiked food sample. Both the qPCR and ddPCR assays exhibited good linearity with a high coefficient of determination in the pure culture and spiked food sample (R2 ≥ 0.996). The ddPCR showed a 10-fold lower limit of detection, suggesting that a ddPCR is more sensitive than a qPCR. However, a ddPCR has limitations in the absolute quantitation of high bacterial concentrations (>106 CFU/mL). In conclusion, a ddPCR can be a reliable method for detecting and quantifying lactic acid bacteria in food.
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Affiliation(s)
| | | | | | | | | | | | - Hae-Yeong Kim
- Correspondence: ; Tel.: +82-31-201-2600; Fax: +82-31-204-8116
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Wang J, Yang Q, Liu H, Chen Y, Jiang W, Wang Y, Zeng H. A nanomaterial-free and thionine labeling-based lateral flow immunoassay for rapid and visual detection of the transgenic CP4-EPSPS protein. Food Chem 2022; 378:132112. [PMID: 35033711 DOI: 10.1016/j.foodchem.2022.132112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 12/14/2021] [Accepted: 01/06/2022] [Indexed: 12/28/2022]
Abstract
Nanomaterial-based lateral flow immunoassays (LFIAs) have been widely used for the on-site detection of genetically modified components. However, the practical applications are often limited by the complex matrix, such as in red samples. In this study, a thionine (Thi) labeling-based LFIA was developed for the first time to detect CP4-EPSPS protein. The optimal labeling concentration of Thi was 0.5 mg/mL, and the antibody could be rapidly coupled to Thi in 10 min. The visual limit of detection (vLOD) levels for transgenic soybean, sugar beet, and cotton containing the CP4-EPSPS protein reached 0.05%, 0.1%, and 0.1%, respectively, and had no interference from other proteins. After storage at 4 °C for three months, the LFIA sensitivity remained unchanged and showed good stability. This method could be used to screen and detect a variety of transgenic crops containing the CP4-EPSPS protein, and the results were consistent with the current standard assay. This study pioneered the development of an immunochromatographic method using Thi as a marker and applied it to the detection of the CP4-EPSPS protein in herbicide-tolerant transgenic crops. This provides a new method for the rapid immunoassay of Thi as a dye and has good prospects for practical application.
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Affiliation(s)
- Jinbin Wang
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China; Crops Ecological Environment Security Inspection and Supervision Center (Shanghai), Ministry of Agriculture and Rural Affairs, Shanghai 201106, China
| | - Qianwen Yang
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China; School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China
| | - Hua Liu
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China; Crops Ecological Environment Security Inspection and Supervision Center (Shanghai), Ministry of Agriculture and Rural Affairs, Shanghai 201106, China
| | - Yifan Chen
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China; Crops Ecological Environment Security Inspection and Supervision Center (Shanghai), Ministry of Agriculture and Rural Affairs, Shanghai 201106, China
| | - Wei Jiang
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China; Crops Ecological Environment Security Inspection and Supervision Center (Shanghai), Ministry of Agriculture and Rural Affairs, Shanghai 201106, China
| | - Yu Wang
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China; School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China
| | - Haijuan Zeng
- Biotechnology Research Institute, Shanghai Academy of Agricultural Sciences, Key Laboratory of Agricultural Genetics and Breeding, Shanghai 201106, China; Crops Ecological Environment Security Inspection and Supervision Center (Shanghai), Ministry of Agriculture and Rural Affairs, Shanghai 201106, China.
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