## 1 Introduction  
Bananas and plantains are important food crops and daily sources of carbohydrates for at least 100 million people on the African continent [1; 2; 3]. The importance of bananas as a staple food is exemplified by Uganda, where per capita consumption reaches approximately 220-400 kg per year. Of the 20.4 million tons of bananas produced in East and Southern Africa, only 1% is exported, mainly by Uganda and Tanzania. Approximately 4% of the 11 million tons produced in West and Central Africa are exported, mainly by Cote d'Ivoire and Cameroon [4; 5]. In Africa, the production of bananas and plantains is often hampered by biological and environmental constraints. Many pests and diseases have been introduced to the continent through infected planting material. With the expansion of the banana industry in African countries, these diseases and pests have spread to several new areas. In many areas, disease-causing pathogens occur in epidemic proportions. The enormous costs involved in controlling some of these diseases make it almost impossible to continue banana production in severely affected areas [6]. In Mozambique, bananas (_Musa_ spp.) are produced mainly on small farms; however, some large farms are found around the provinces of Maputo, Gaza, Nampula and Manica. These farms mainly cultivate Cavendish varieties and supply large cities such as Maputo and Beira and the markets of South Africa, Botswana and the Kingdom of eSwatini. Currently, banana plantations (farms) occupy 62,000 ha in Mozambique, with an estimated production of 470,000 thousand tons per year [7]. Production on small farms in southern Mozambique (provinces of Maputo and Gaza) averages 45 tons per ha for a production area of 3216 ha. In addition to the various pests (nematodes and weevils) and diseases (Sigatoka, Fusarium disease or Panama disease (FocTR4) and currently bunchy top) that can affect banana crops, the lack of production knowledge, low performance, low soil fertility and long drought periods (particularly in the south of the country) are factors that hinder crop management [7]. Among the diseases cited, fusariosis or Panama disease (FocTR4) and banana bunchy top disease (BBTD) have been the most important. BBTD, whose etiological agent is the banana bunchy top virus (BBTV), was introduced and reported for the first time in sub-Saharan Africa (SSA) in the 1960s in the Democratic Republic of Congo [8]. Since then, the spread of BBTV has been confirmed in 16 countries in the Central, Southern and West African regions, and it was first recorded in South Africa in 2015 [9] and in Mozambique in June 2016, in the Chokwe irrigated perimeter, more specifically in the Primeira Zona locality, in the province of Gaza [7]. BBTV belongs to the domain _Monodnariria_, kingdom _Shotokwire_, phylum _Cresduavricota_, class _Arfivricetes_, order _Mulpavriales_, family _Nanovividae_ and genus _Babuvirus_[10]. BBTV affects only members of the genus _Musa_ and is transmitted in a persistent circulatory manner by its only known vector, _Pentalonia nigronervosa_ Coq. [11; 12]. The BBTV genome has six circular single-stranded DNA (ssDNA) components (R-DNA, U3-DNA, S-DNA, M-DNA, C-DNA and N-DNA), each approximately 1 kilobase (kb) in size [13]. Each component potentially encodes a protein, except for R-DNA, which encodes two proteins linked to viral replication [14; 15]. S-DNA encodes the capsid protein (CP), which forms isometric particles and aids in genome packaging [16]. C-, N- and M-DNA encode cell cycle binding proteins (Clink), nuclear transport proteins (NSPs) and movement proteins (MPs), respectively [17; 18; 19]. The function of U3-DNA remains unknown for BBTV. Rep and CPs are evolutionarily more conserved than the other proteins and therefore serve as useful markers for the identification and classification of ssDNA viruses [20]. The R gene has been used to classify isolates from different countries located in distinct geographical regions [21].