College of Horticulture and Plant Protection, Inner Mongolia Agricultural University, 010018 Hohhot, PR China.
Julius Kühn-Institut, Federal Research Centre for Cultivated Plants, Institute for Plant Protection in Fruit Crops and Viticulture, D-69221 Dossenheim, Germany.
Virus Res. 2020 Jan 15;276:197790. doi: 10.1016/j.virusres.2019.197790. Epub 2019 Oct 23.
Apple stem grooving virus (ASGV) belongs to the genus Capillovirus within the family Betaflexiviridae. In this work, we described the construction of full-length infectious cDNA clones of ASGV isolate jilin-shaguo (JL-SG) using the Gibson Assembly approach (New England BioLabs). The isolate was previously detected in a Chinese pear-leaf crab apple (Malus asiatica Nakai.) in Baicheng, Jilin province, China. Two full-length cDNA clones of ASGV JL-SG were obtained, and they are identical to each other in sequence. The full-length cDNA clone was infectious on Chenopodium quinoa, Nicotiana glutinosa, and N. occidentalis 37B via agroinfiltration. Through sap inoculation, the infection was additionally spread to C. amaranticolor. N. benthamiana could not be infected, neither through agroinfiltration nor sap inoculation. In infected herbaceous plants, typical ASGV particles with morphology of flexuous filaments were observed by transmission electron microscope (TEM). Moreover, seeds of infected N. glutinosa and N. occidentalis 37B were collected and germinated, the seedlings were ASGV-free in RT-PCR test, suggesting ASGV JL-SG is not seed-transmissible in the tested Nicotiana species. In addition, the cDNA clone was agroinfiltrated into seedlings of Malus pumila cv. Fuji. The infection was symptomless, and can be spread to C. quinoa via sap inoculation, causing typical symptoms. ASGV JL-SG was also detected by RT-PCR in the infected Fuji plants, however, no virion was observed by TEM.
苹果茎沟病毒（ASGV）属于贝塔病毒科毛形病毒属。在这项工作中，我们使用 Gibson 组装方法（New England BioLabs）构建了 ASGV 分离株吉林沙果（JL-SG）全长感染性 cDNA 克隆。该分离株先前在中国吉林省白城市的中国梨叶海棠（Malus asiatica Nakai.）中被检测到。获得了两个 ASGV JL-SG 的全长 cDNA 克隆，它们在序列上完全相同。全长 cDNA 克隆可通过农杆菌浸润在藜麦、烟草和 N. occidentalis 37B 上感染。通过汁液接种，感染还会传播到 C. amaranticolor。N. benthamiana 既不能通过农杆菌浸润，也不能通过汁液接种感染。在感染的草本植物中，通过透射电子显微镜（TEM）观察到具有弯曲丝状形态的典型 ASGV 颗粒。此外，收集并萌发了感染的 N. glutinosa 和 N. occidentalis 37B 的种子，RT-PCR 检测表明这些种子中没有 ASGV，表明在测试的烟草物种中，ASGV JL-SG 不是种子传播的。此外，将 cDNA 克隆农杆菌浸润到富士苹果幼苗中。感染无症状，可通过汁液接种传播至藜麦，引起典型症状。在感染的富士苹果植株中也通过 RT-PCR 检测到了 ASGV JL-SG，但 TEM 未观察到病毒粒子。
