Longué D R S, Galzi-Pinel A, Semballa S, Zinga I, Fargette D, Traoré O
Laboratoire des Sciences Biologiques et Agronomiques pour le Développement (LASBAD), Université de Bangui, BP 908, Bangui, Central African Republic.
Institut de Recherche pour le Développement (IRD), UMR Résistance des Plantes aux Bioagresseurs, BP 64501, Montpellier 34394, France.
Plant Dis. 2014 Jan;98(1):162. doi: 10.1094/PDIS-04-13-0418-PDN.
Rice yellow mottle virus (RYMV, genus Sobemovirus) is a major biotic constraint to rice production in Africa. First reported in Kenya in 1966, RYMV was later found in most countries in Africa where rice (Oryza sativa, O. glaberrima) is grown (4). In the Central African Republic, the disease has never been reported in rice fields. In October 2011, plants with leaf yellowing and mottling symptoms were observed in large irrigated rice production schemes about 30 km west of Bangui, the capital of the Central African Republic, and in lowland subsistence fields in Bangui outskirts. Disease incidence was estimated at 5 to 10%, causing small patches in the fields. Mechanical inoculation with extracts of symptomatic leaves reproduced the typical yellow mottle symptoms on the susceptible O. sativa cultivar BG90-2 6 to 9 days after inoculation. Symptomatic leaves of 12 cultivated plants collected in seed beds or in fields reacted positively when tested by ELISA with polyclonal antisera raised against a Madagascan isolate of RYMV (1). Discriminating monoclonal antibodies showed that the samples contained RYMV serotype 1, a serotype found in West and Central Africa (1). Total RNA was extracted by the RNeasy Plant Mini kit (QIAGEN, Hilden, Germany) from six samples. The 720-nt RYMV coat protein gene was amplified by reverse transcriptase (RT)-PCR with primers 5'CTCCCCCACCCATCCCGAGAATT3' and 5'CAAAGATGGCCAGGAA3' (2). RT-PCR products were directly sequenced and sequences were deposited in GenBank (Accession Nos. KF054740 through KF054745). These six sequences showed over 98% identity with each other, and were found to be closely related to sequences of isolates from Chad and Cameroon in Central Africa (3). Knowledge of the presence of RYMV in the Central African Republic is important since rice cultivation has intensified in this country. In addition, rice is also increasingly considered as one of the main staple crops in the country. References: (1) D. Fargette et al. Arch. Virol. 147:583, 2002. (2) A. Pinel et al. Arch. Virol. 145:1621, 2000. (3) O. Traoré et al. Plant Dis. 96:1230, 2001. (4) O. Traoré et al. Virus Res. 141:258, 2009.
水稻黄斑驳病毒（RYMV， sobemovirus属）是非洲水稻生产的主要生物制约因素。1966年在肯尼亚首次报道，后来在非洲大多数种植水稻（亚洲栽培稻、光稃稻）的国家都发现了RYMV（4）。在中非共和国，稻田中从未报道过这种病害。2011年10月，在中非共和国首都班吉以西约30公里处的大型灌溉水稻生产区以及班吉郊区的低地自给农田中，观察到有叶片发黄和斑驳症状的植株。病害发生率估计为5%至10%，在田间形成小块病斑。用有症状叶片的提取物进行机械接种，在接种后6至9天，在易感的亚洲栽培稻品种BG90 - 2上再现了典型的黄斑驳症状。用针对马达加斯加RYMV分离株制备的多克隆抗血清进行ELISA检测时，从苗床或田间采集的12株栽培植物的有症状叶片呈阳性反应（1）。鉴别性单克隆抗体表明，这些样品含有RYMV血清型1，这是在西非和中非发现的一种血清型（1）。用RNeasy植物微量提取试剂盒（QIAGEN，德国希尔德）从6个样品中提取总RNA。用引物5'CTCCCCCACCCATCCCGAGAATT3'和5'CAAAGATGGCCAGGAA3'通过逆转录酶（RT）-PCR扩增720个核苷酸的RYMV外壳蛋白基因（2）。RT-PCR产物直接测序，序列存入GenBank（登录号KF054740至KF054745）。这6个序列彼此间的同源性超过98%，并且发现与中非乍得和喀麦隆分离株的序列密切相关（3）。了解中非共和国存在RYMV很重要，因为该国的水稻种植已经加强。此外，水稻也越来越被视为该国的主要主食作物之一。参考文献：（1）D. Fargette等人，《病毒学档案》147:583，2002年。（2）A. Pinel等人，《病毒学档案》145:1621，2000年。（3）O. Traoré等人，《植物病害》96:1230，2001年。（4）O. Traoré等人，《病毒研究》141:258，2009年。
