Monoclonal antibodies for differentiating infections of three serological-related tospoviruses prevalent in Southwestern China.
BACKGROUND
The thrips-borne tospoviruses Calla lily chlorotic spot virus (CCSV), Tomato zonate spot virus (TZSV) and a new species provisionally named Tomato necrotic spot associated virus (TNSaV) infect similar crops in southwestern China. The symptoms exhibiting on virus-infected crops are similar, which is difficult for distinguishing virus species by symptomatology. The sequences of nucleocapsid proteins (NPs) of CCSV, TNSaV and TZSV share high degrees of amino acid identity with each other, and their serological relationship was currently demonstrated from the responses of the previously reported monoclonal antibodies (MAbs) against the NP of CCSV (MAb-CCSV-NP) and the nonstructural NSs protein of Watermelon silver mottle virus (WSMoV) (MAb-WNSs). Therefore, the production of virus-specific antibodies for identification of CCSV, TNSaV and TZSV is demanded to improve field surveys.


METHODS
The NP of TZSV-13YV639 isolated from Crinum asiaticum in Yunnan Province, China was bacterially expressed and purified for producing MAbs. Indirect enzyme-linked immunosorbent assay (ELISA) and immunoblotting were conducted to test the serological response of MAbs to 18 tospovirus species. Additionally, the virus-specific primers were designed to verify the identity of CCSV, TNSaV and TZSV in one-step reverse transcription-polymerase chain reaction (RT-PCR).


RESULTS
Two MAbs, denoted MAb-TZSV-NP(S15) and MAb-TZSV-NP(S18), were screened for test. MAb-TZSV-NP(S15) reacted with CCSV and TZSV while MAb-TZSV-NP(S18) reacted specifically to TZSV in both indirect ELISA and immunoblotting. Both MAbs can be used to detect TZSV in field-collected plant samples. The epitope of MAb-TZSV-NP(S18) was further identified consisting of amino acids 78-86 (HKIVASGAD) of the TZSV-13YV639 NP that is a highly conserved region among known TZSV isolates but is distinct from TNSaV and TZSV.


CONCLUSIONS
In this study, two MAbs targeting to different portions of the TZSV NP were obtained. Unlike MAb-CCSV-NP reacted with TNSaV as well as CCSV and TZSV, both TZSV MAbs can be used to differentiate CCSV, TNSaV and TZSV. The identity of CCSV, TNSaV and TZSV was proven by individual virus-specific primer pairs to indicate the correctness of serological responses. We also proposed an serological detection platform using MAb-CCSV-NP, MAb-TZSV-NP(S15) and MAb-TZSV-NP(S18) to allow researchers and quarantine staff to efficiently diagnose the infections of CCSV, TNSaV and TZSV in China and other countries.
Department of Biotechnology, Asia University, Wufeng, Taichung, 41354, Taiwan.
Yu-Han
YH
Chen
Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Key Laboratory of Southwestern Crop Gene Resources and Germplasm Innovation of Ministry of Agriculture, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650223, China. dongjhn@126.com.
Jiahong
J
Dong
Department of Biotechnology, Asia University, Wufeng, Taichung, 41354, Taiwan.
Wan-Chu
WC
Chien
Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Key Laboratory of Southwestern Crop Gene Resources and Germplasm Innovation of Ministry of Agriculture, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650223, China.
Kuanyu
K
Zheng
Yunnan Provincial Key Laboratory of Agricultural Biotechnology, Key Laboratory of Southwestern Crop Gene Resources and Germplasm Innovation of Ministry of Agriculture, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Kunming, 650223, China.
Kuo
K
Wu
Department of Plant Pathology, National Chung Hsing University, Taichung, 40227, Taiwan.|NCHU-UCD Plant and Food Biotechnology Center, National Chung Hsing University, Taichung, 40227, Taiwan.
Shyi-Dong
SD
Yeh
Department of Biotechnology, Asia University, Wufeng, Taichung, 41354, Taiwan.
Jing-Hua
JH
Sun
Department of Biotechnology, Asia University, Wufeng, Taichung, 41354, Taiwan.
Yun-Chi
YC
Wang
Department of Biotechnology, Asia University, Wufeng, Taichung, 41354, Taiwan. kikichenwolf@hotmail.com.|Department of Medical Research, China Medical University Hospital, China Medical University, Taichung, 40402, Taiwan. kikichenwolf@hotmail.com.
Tsung-Chi
TC
Chen
D000911:Antibodies, Monoclonal / Q000276:immunology*; D000914:Antibodies, Viral / Q000276:immunology*; D000956:Antigens, Viral / Q000032:analysis* / Q000276:immunology; D002681:China; D004797:Enzyme-Linked Immunosorbent Assay; D015151:Immunoblotting; D010935:Plant Diseases / Q000821:virology*; D017865:Tospovirus / Q000145:classification* / Q000276:immunology / Q000302:isolation & purification*
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral
Diagnosis; Monoclonal antibody; Quarantine; Serological assay; Tospovirus