종자의 수입 시, 검역관련 종자전염바이러스는 가장 문제가 되는 식물병이다. 본 연구에서 PCR 검역체계가 보고되지 않은 3종의 종자전염바이러스, Cherry rasp leaf virus (CRLV), Spinach latent virus (SpLV) 및 White clover mosaic virus (WClMV)를 검출하기 위하여 reverse transcription polymerase chain reaction (RT-PCR)과 nested polymerase chain reaction (nested PCR) 방법을 도입하였다. 각각의 바이러스별로 2 세트의 RT-PCR primer가 선발되었으며, 증폭산물에서 더욱 높은 감도로 검출 할 수 있는 nested PCR primer set를 개발하였다. 본 연구에서 사용한 RT-PCR과 nested PCR 방법은 종자로부터 CRLV, SpLV 및 WClMV를 검역하는 고효율적 진단시스템으로 제공될 것이다.

Soybean mosaic virus (SMV) is a prevalent pathogen that causes significant yield reduction in soybean production worldwide. SMV belongs to potyvirus and causes typical symptoms such as mild mosaic, mosaic and lethal necrosis. SMV is seed-borne and also transmitted by aphid. Eleven SMV strains, G1 to G7, G5H, G6H, G7H, and G7a were reported in soybean varieties in Korea. A reverse transcription loop-mediated isothermal amplification (RT-LAMP) method allowed one-step detection of gene amplification by simple procedure and needed only a simple incubator for isothermal template. This RT-LAMP method allowed direct detection of RNA from virus-infected plants without thermal cycling and gel electrophoresis. In this study, we designed RT-LAMP primers named SML-F3/B3/FIP/BIP from coat protein gene sequence of SMV. After the reaction of RT-LAMP, products were identified by electrophoresis and with the detective fluorescent dye, SYBR Green I. under daylight and UV light. Opmtimal reaction condition was at 58℃ for 60min and the primers of RT-LAMP showed the specificity for nine SMV strains tested in this study.

Generally, the virus was detected by the ELISA using the serological method and RT-PCR based on the genetic information. Recently, NGS (next-generation nucleotide sequencing) has been used in genome analysis and diseases diagnostics. To identify distribution aspects of viruses, we collected diseased samples twice in soybean breeding field. After extraction of total RNA from the collected bulk samples, RNA was sequenced by the NGS method. The NGS data were analyzed using the bioinformatics software. With newly produced NGS data, the identification of distribution aspects of organisms in field was estimated in this study. Sequence based identification method should be more accurate diagnostic tools of the target diseases and be able to predict occurrence of potential and new pathogens. NGS method will also provide the basic data by identifying the distribution of using bacteria. In this study, we analyzed the extracted RNA from the collection of approximately 3000 samples. Consequently, we confirmed the following types: the 7,089 kinds of bacteria including Burkholderiaceae, the 13,397 kinds of Eukaryota, the 952 kinds of viruses from the first bulk samples, the 4,160 kinds of bacteria including Burkholderiaceae, the 10,475 kinds of Eukaryota, and the 576 kinds of viruses from the second bulk samples

In this study, we constructed viral vector for soybean by using Soybean yellow common mosaic virus (SYCMV) infecting both Glycine max and Glycine soja. SYCMV-derived viral vector was tested to use as Virus-induced gene silencing (VIGS) vector for functional analysis of soybean genes and as protein expression vector for foreign protein expression. In vitro transcript with 5’ cap analog m7GpppG from a full-length infectious vector of SYCMV driven by T7 promoter was inoculated to soybean to test infectivity of the clone (pSYCMVT7-full). 5’-capped transcript was able to infect soybean plants. The symptoms observed in soybean plants infected by either the vector or the sap from SYCMV-infected leaves were indistinguishable, suggesting that the vector had an equal biological activity shown by virus itself. To further utilize the vector, an additional DNA-based vector was constructed. The full-length cDNA was inserted into a binary vector flanked by CaMV 35S promoter and the nopaline synthase terminator (pSYCMV35S-full). To test if the vector infects soybean and subsequently induces gene silencing, we prepared two constructs containing fragments of Phytoene desaturase (PDS) gene (pSYCMV35S-PDS1) and small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (rbcS) gene (pSYCMV35S-rbcS2) from soybean plant. Plants infiltrated with the constructs through Agrobacterium-mediated method showed distinct symptoms such as photobleaching in plants infiltrated with pSYCMV-PDS1 and pale green or yellowing in plants infiltrated with pSYCMV-rbcS2. In addition, down-regulations of mRNA levels of two genes were confirmed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). To test if the vector can be used for foreign protein expression in soybean plants, we prepared a construct encoding amino acids 135-160 of VP1 FMDV serotype O1 Campos (O1C) (pSYCMV35S-FMDV). Plants infiltrated with the construct through Agrobacterium-mediated method showed that soybean plant infiltrated with pSYCMV35S-FMDV only was detected by Western blotting using O1C antibody. These results support that SYCMV-derived viral vector can be used as VIGS vector or protein expression vector in soybean plants.