First Report of Banana bunchy top virus in Banana and Plantain (Musa spp.) in Nigeria

Abstract

Plantain and banana (Musa spp.) are among the most important staple crops for food and income generation for the rural and urban populations in the humid forest agroecological zone of West Africa. Until recently, Cucumber mosaic virus (genus Cucumovirus) and Banana streak virus (genus Badnavirus) were the only viruses reported to occur in Musa spp. in West Africa. In 2011, an outbreak of banana bunchy top disease (BBTD) caused by Banana bunchy top virus (BBTV; genus Babuvirus, family Nanoviridae) was reported in Ouémé Département (6°30′N and 2°36′E) in the Republic of Benin (2). BBTV is one of the most economically important pathogens of Musa spp. It is well established in Central Africa and also in Angola, Malawi, and Zambia in Southern Africa (2). Plants infected at early growth stages are severely dwarfed and do not bear fruit. BBTV is transmitted by the banana aphid Pentalonia nigronervosa, which is widespread in Africa (1). The regions in the Republic of Benin affected by BBTV border Ogun State (7°00′N and 3°35′E) of Nigeria. Epidemiological investigations were conducted during May 2012 at 31 locations in Ogun State to determine the potential risk of BBTV spreading into Nigeria. Plants with typical symptoms of BBTD (stunting, narrow and shortened leaves, chlorotic streaks on petioles and pseudostem) were observed in four locations: Ilashe, Odan-Itoro, Ido-Ologun, and Igbogila. Total DNA was extracted from 90 leaf samples randomly collected from symptomatic and asymptomatic banana and plantain plants in these areas. Samples were tested for BBTV by polymerase chain reaction (PCR) using primer pairs, mREP-F and mREP-R, which amplifies a 241-bp of BBTV DNA-mRep segment (1), and Scp-F and Scp-R specific for approximately 1075-bp BBTV DNA-S that encodes coat protein gene (1). The amplicons of expected size were obtained from 17 of 90 samples analyzed (18.8%). BBTV in the symptomatic plants was further confirmed by nucleic acid spot hybridization (NASH) assay using DIG-labeled 1,075-bp probe corresponding to coat protein gene and chromogenic detection as per the previously described protocol (3). The DIG-probe specifically reacted with nucleic acid from the symptomatic plants, but not with negative controls, providing conclusive evidence for the BBTV. The PCR products of DNA-mRep segment amplified from three banana plants infected with BBTV collected in Ilashe (Ipokia Local Government Area) were purified and sequenced in both directions. The sequences of these isolates were 100% identical with each other (GenBank Accession Nos. JX290301, JX290302, and JX290303). A BLASTn search revealed 100% nucleotide sequence identity with a BBTV isolate from Benin (JQ437548) and 99 to 100% identity with DNA-mRep sequences of several other BBTV isolates from Africa, Australia, India, and the South Pacific. Further analysis of the 241-bp mRep gene sequences with Neighbor-Joining phylogenetic analysis grouped the BBTV isolate with the South Pacific isolates. To our knowledge, this is the first report of BBTV in Nigeria. This underscores need for surveys to assess the extent of BBTV spread in Nigeria and strict implementation of phytosanitary measures, including restrictions on the movement of planting material from disease-affected regions, to prevent further spread of this important disease. References: (1) P. L. Kumar et al. Virus Res. 159:171, 2011. (2) B. Lokossou et al. New Dis. Rep. 25:13, 2012. (3) W. S. Xie and J. S. Hu. Phytopathol. 85:339, 1995.

Prevalence of viruses infecting plantain (Musa sp., AAB genome) in the major growing regions in Cote dIvoire

“…Banana bunchy top virus is one of the most damaging viruses on banana (Musa sp.) (Kumar et al, 2011) and it is expanding in Africa including Benin and Nigeria in West Africa (Kumar et al, 2011;Lokossou et al, 2012;Adegbola et al, 2013). However, unlike the other 4 banana viruses causing symptoms including mosaics that we indexed, Banana bunchy top disease has very characteristic symptoms on banana.…”

Modifying Bananas: From Transgenics to Organics?

“…Spread by aphids and via infected planting material, the disease is aggressively moving through Africa, recently destroying the smallholder-based Cavendish industry in Malawi and becoming established in Nigerian plantains [24][25][26]. Importantly, the disease can be controlled, but cannot be eradicated in well organised commercial settings through the use of virus-free planting material and the regular plantation inspection and eradication of infected plants.…”

RNAi technology for management of banana bunchy top disease

“…The disease is caused by banana bunchy top virus (BBTV, genus Babuvirus) and transmitted by banana aphids (Pentalonia nigronervosa) and the transboundary exchange of infected planting materials. BBTD was first reported in the 1880s in Fiji (Magee, 1927) and has since been spreading to other banana producing countries in the world including several African countries, Oceania, Asia, and South Pacific (Figure 1; Adegbola, Ayodeji, Awosusi, Atiri, & Kumar, 2013;Jooste, Wessels, & Van der Merwe, 2016;Kagy, Thomas, Sharman, & Mademba-Sy, 2001; Kenyon, Brown, & Khonje, 1997;Khalid & Soomro, 1993;Kumar et al, 2011;Lokossou et al, 2012;Oben et al, 2009;Xie & Hu, 1995). In Africa, BBTD has spread to 17 different countries, and neighboring banana producing countries are at a high risk of being affected (Adegbola et al, 2013;Blomme et al, 2013;Jooste et al, 2016).…”