Babu B, Dankers H, George S, Wright D, Marois J, Paret M
North Florida Research and Education Center, University of Florida, 155 Research Road, Quincy 32351.
Plant Dis. 2013 Dec;97(12):1664. doi: 10.1094/PDIS-05-13-0500-PDN.
Brassica carinata L. Braun (Ethiopian mustard) is an annual oil seed crop currently being evaluated for its potential use as a source of biofuel. Due to its high content of erucic acid, it provides a biodegradable non-fossil fuel feedstock that has many applications ranging from biofuels to other industrial uses such as polymers, waxes, and surfactants. Moreover, high glucosinolate content adds the scope of B. carinata being used as a bio-fumigant. B. carinata is amenable to low input agriculture and has great economic potential to be used as a winter crop, especially in the southeastern United States. Virus-like leaf symptoms including mosaic, ringspot, mottling, and puckering were observed on B. carinata (cvs. 080814 EM and 080880 EM) in field trials at Quincy, FL, during spring 2013, with disease incidence of >80%. A more extensive survey of the same field location indicated that mosaic symptoms were the most common. Viral inclusion assays (1) of leaves with a range of symptoms indicated the presence of potyvirus-like inclusion bodies. Total RNA extracts (RNeasy Plant Mini Kit, Qiagen Inc., Valencia, CA) from six symptomatic samples and one non-symptomatic B. carinata sample were subjected to reverse transcription (RT)-PCR assays using SuperScript III One-Step RT-PCR System (Invitrogen, Life Technologies, NY), and two sets of potyvirus-specific degenerate primers MJ1-F and MJ2-R (2) and NIb2F and NIb3R (3), targeting the core region of the CP and NIb, respectively. The RT-PCR assays using the CP and NIb specific primers produced amplicons of 327 bp and 350 bp, respectively, only in the symptomatic leaf samples. The obtained amplicons were gel-eluted and sequenced directly (GenBank Accession Nos. KC899803 to KC899808 for CP and KC899809 to KC899813 for NIb). BLAST analysis of these sequences revealed that they came from Turnip mosaic virus (TuMV). Pairwise comparisons of the CP (327 bp) and NIb (350 bp) segments revealed 98 to 99% and 96 to 98% nucleotide identities, respectively, with corresponding sequences of TuMV isolates. These results revealed the association of TuMV with symptomatic B. carinata leaf samples. Although TuMV has been reported from B. carinata in Zambia (4), this is the first report of its occurrence on B. carinata in the United States. Considering the importance of B. carinata as a biofuel source, this report underscores the need for developing effective virus management strategies for the crop. References: (1) R. G. Christie and J. R. Edwardson. Plant Dis. 70:273, 1986. (2) M. Grisoni et al. Plant Pathol. 55:523, 2006. (3) L. Zheng et al. Plant Pathol. 59:211, 2009. (4) D. S. Mingochi and A. Jensen. Acta Hortic. 218:289, 1988.
埃塞俄比亚芥（Brassica carinata L. Braun）是一种一年生油料作物，目前正在评估其作为生物燃料来源的潜在用途。由于其芥酸含量高，它提供了一种可生物降解的非化石燃料原料，有许多应用，从生物燃料到其他工业用途，如聚合物、蜡和表面活性剂。此外，高硫代葡萄糖苷含量增加了埃塞俄比亚芥用作生物熏蒸剂的范围。埃塞俄比亚芥适合低投入农业，作为冬季作物具有很大的经济潜力，特别是在美国东南部。2013年春季，在佛罗里达州昆西的田间试验中，在埃塞俄比亚芥（品种080814 EM和080880 EM）上观察到了类似病毒的叶片症状，包括花叶、环斑、斑驳和褶皱，发病率>80%。对同一田间地点进行的更广泛调查表明，花叶症状最为常见。对一系列症状叶片进行的病毒包涵体检测（1）表明存在类马铃薯Y病毒包涵体。使用SuperScript III一步法RT-PCR系统（Invitrogen，Life Technologies，纽约），对六个有症状样本和一个无症状埃塞俄比亚芥样本的总RNA提取物（RNeasy植物小提试剂盒，Qiagen公司，加利福尼亚州瓦伦西亚）进行逆转录（RT）-PCR检测，并使用两组马铃薯Y病毒特异性简并引物MJ1-F和MJ2-R（2）以及NIb2F和NIb3R（3），分别靶向外壳蛋白（CP）和核内含体b（NIb）的核心区域。使用CP和NIb特异性引物进行的RT-PCR检测仅在有症状的叶片样本中产生了分别为327 bp和350 bp的扩增子。将获得的扩增子进行凝胶洗脱并直接测序（CP的GenBank登录号为KC899803至KC899808，NIb的GenBank登录号为KC899809至KC899813）。对这些序列的BLAST分析表明它们来自芜菁花叶病毒（TuMV）。CP（327 bp）和NIb（350 bp）片段的成对比较显示，与TuMV分离株的相应序列分别具有98%至99%和96%至98%的核苷酸同一性。这些结果揭示了TuMV与有症状的埃塞俄比亚芥叶片样本之间的关联。尽管在赞比亚的埃塞俄比亚芥中已报道过TuMV（4），但这是其在美国埃塞俄比亚芥上发生的首次报道。考虑到埃塞俄比亚芥作为生物燃料来源的重要性，本报告强调了为该作物制定有效的病毒管理策略的必要性。参考文献：（1）R. G. Christie和J. R. Edwardson。《植物病害》70:273，1986年。（2）M. Grisoni等人。《植物病理学》55:523，2006年。（3）L. Zheng等人。《植物病理学》59:211，2009年。（4）D. S. Mingochi和A. Jensen。《园艺学报》218:289，1988年。
