Jiang Hua, Li Kai, Gai Junyi
Soybean Research Institute & MARA National Center for Soybean Improvement & MARA Key Laboratory of Biology and Genetic Improvement of Soybean (General) & State Key Laboratory for Crop Genetics and Germplasm Enhancement & Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China.
Front Plant Sci. 2021 Nov 22;12:739971. doi: 10.3389/fpls.2021.739971. eCollection 2021.
Soybean mosaic virus (SMV) is a prevalent pathogen of soybean (). Pyramiding multiple SMV-resistance genes into one individual is tedious and difficult, and even if successful, the obtained multiple resistance might be broken by pathogen mutation, while targeting viral genome host-induced gene silencing (HIGS) has potential to explore broad-spectrum resistance (BSR) to SMV. We identified five conserved target fragments (CTFs) from to using multiple sequence alignment of 30 SMV genome sequences and assembled the corresponding target-inverted-repeat constructs (TIRs) from S1-TIR to S5-TIR. Since the inefficiency of soybean genetic transformation hinders the function verification of batch TIRs in SMV-resistance, the chimeric-SMV and pSMV-GUS pathosystems combined with -mediated transient expression assays were invented and used to test the efficacy of these TIRs. From that, S1-TIR assembled from 462 bp CTF- with 92% conservation rate performed its best on inhibiting SMV multiplication. Accordingly, S1-TIR was transformed into SMV-susceptible soybean , the resistant-healthy transgenic T-plants were then picked out detached-leaf inoculation assay with the stock-plants continued for progeny reproduction (T dual-utilization). All the four T transgenic progenies showed immunity to all the inoculated 11 SMV strains under individual or mixed inoculation, achieving a strong BSR. Thus, optimizing target for HIGS transient chimeric-SMV and pSMV-GUS assays is crucial to drive robust resistance to SMV in soybean and the transgenic S1-TIR-lines will be a potential breeding source for SMV control in field.
大豆花叶病毒（SMV）是大豆中一种普遍存在的病原体。将多个SMV抗性基因聚合到一个个体中既繁琐又困难，而且即使成功，获得的多重抗性也可能因病原体突变而被打破，而靶向病毒基因组的宿主诱导基因沉默（HIGS）有潜力探索对SMV的广谱抗性（BSR）。我们通过对30个SMV基因组序列进行多序列比对，从[具体范围]中鉴定出5个保守靶片段（CTF），并组装了从S1-TIR到S5-TIR的相应靶反向重复构建体（TIR）。由于大豆遗传转化效率低下阻碍了批量TIR在SMV抗性方面的功能验证，因此发明了嵌合SMV和pSMV-GUS病理系统并结合[具体介导方式]介导的瞬时表达分析来测试这些TIR的功效。据此，由462 bp的CTF-[具体编号]组装而成、保守率为92%的S1-TIR在抑制SMV增殖方面表现最佳。因此，将S1-TIR转化到对SMV敏感的大豆[品种名称]中，然后挑选出抗性健康的转基因T植株，通过与母本植株进行离体叶片接种试验来进行后代繁殖（T代双利用）。所有四个T代转基因后代在单独接种或混合接种时，对所有接种的11个SMV株系均表现出免疫，实现了强大的BSR。因此，优化HIGS的靶标以及瞬时嵌合SMV和pSMV-GUS分析对于在大豆中驱动对SMV的强大抗性至关重要，并且转基因S1-TIR株系将成为田间控制SMV的潜在育种资源。
