Occurrence of Banana bunchy top virus in banana and plantain (Musa sp.) in Benin

In July 2011, banana and plantain that displayed stunting and leaf symptoms typical of banana bunchy top disease were observed to be widespread in Dangbo Commune, Ouémé Department, Benin. To identify the cause of the disease, a roving survey was conducted in December 2011 in nine locations in Avrankou, Dangbo, Akpro-Missérété and Porto-Novo Communes, in Ouémé. In each location, the incidence of symptom-bearing plants was estimated from counts of 15 mats, and samples were collected for Banana bunchy top virus (BBTV) assessment. Approximately 60% of the 94 banana mats assessed had plants exhibiting typical symptoms of BBTV infection - chlorotic leaf margins, dark green streaks on petioles, narrow leaves that bunched at the top, and severe stunting. Total DNA was extracted from 25 leaf samples collected from plants with symptoms; they were then tested for BBTV by polymerase chain reaction. The sequences showed 100% nucleotide sequence identity with a BBTV isolate from Cameroon (FJ580970) and 99-100% identity with several other BBTV isolates from the GenBank database belonging to the South Pacific group, which consisted of BBTV isolates from Africa, Australia, India and South Pacific. This finding confirmed that the virus isolate associated with the diseased plants in Benin was of the BBTV South Pacific type. This is thought to be the first report of BBTV in Benin. The disease is widespread in all the four communes surveyed

Production of banana bunchy top virus (BBTV)-free plantain plants by in vitro culture

Open Access ArticleBanana Bunchy Top Disease (BBTD) caused by the Banana Bunchy Top Virus (BBTV) is one of the most important banana diseases in the Democratic Republic of Congo. This study focused on the production of BBTV-free plantain seedlings from infected banana plants. A total of 10 suckers from the French plantain Litete (Musa AAB) and the False Horn plantain Libanga Likale (Musa AAB) with advanced BBTD symptoms were collected. Meristematic apices excised from those suckers were cultured in vitro and subcultured five times. The presence of BBTV was evaluated by the Triple-Antibody Sandwich Enzyme-linked Immunosorbent Assay (TAS-ELISA). The BBTV was confirmed in all suckers prior to in vitro culture but 73.3% of Litete plantlets and 66.6% of Libanga Likale plantlets regenerated from meristematic tissues were virus-free. This indicates that in vitro culture is a simple tool to generate BBTV-free plantains

Two distinct nanovirus species infecting faba bean in Morocco

Using monoclonal antibodies raised against a Faba bean necrotic yellows virus (FBNYV) isolate from Egypt and a Faba bean necrotic stunt virus (FBNSV) isolate from Ethiopia, a striking serological variability among nanovirus isolates from faba bean in Morocco was revealed. To obtain a better understanding of this nanovirus variability in Morocco, the entire genomes of two serologically contrasting isolates referred to as Mor5 and Mor23 were sequenced. The eight circular ssDNA components, each identified from Mor5- and Mor23-infected tissues and thought to form the complete nanovirus genome, ranged in size from 952 to 1,005 nt for Mor5 and from 980 to 1,004 nt for Mor23 and were structurally similar to previously described nanovirus DNAs. However, Mor5 and Mor23 differed from each other in overall nucleotide and amino acid sequences by 25 and 26%, respectively. Mor23 was most closely related to typical FBNYV isolates described earlier from Egypt and Syria, with which it shared a mean amino acid sequence identity of about 94%. On the other hand, Mor5 most closely resembled a FBNSV isolate from Ethiopia, with which it shared a mean amino acid sequence identity of approximately 89%. The serological and genetic differences observed for Mor5 and Mor23 were comparable to those observed earlier for FBNYV, FBNSV, and Milk vetch dwarf virus. Following the guidelines on nanovirus species demarcation, this suggests that Mor23 and Mor5 represent isolates of FBNYV and FBNSV, respectively. This is the first report not only on the presence of FBNSV in a country other than Ethiopia but also on the occurrence and complete genome sequences of members of two nanovirus species in the same country, thus providing evidence for faba bean crops being infected by members of two distinct nanovirus species in a restricted geographic area

Banana Bunchy Top Virus Molecular Confirmation and DNA-S Phylogenetic of some Banana Isolates from Indonesia

This study was aimed to confirms the Banana Bunchy Top Virus (BBTV) infection of ten banana accessions from Indonesia through PCR assay using primer of BBTV coat protein (CP) gene, also the sequences characteristics and phylogeny. Preliminary morphological results showed five acessions were positively infected with slight to severe intensity symptoms i.e. Pisang Berlin, Candi, Billa, Morosebo, and Mas Kripik; and five accessions were symptomless i.e. M. acuminata var. rutilifes and M. balbisiana, Pisang Ebung, Madu and Moseng. However, PCR results qualitatively confirms that all accessions were positively infected. Two sizes of amplicons were identified. Pisang Candi isolate was showing ±500 bp amplicons, whereas the others were ±1000-1100 bp. The total aligned and selected BBTV CP sequences of 36 accessions (bananas and other host species) was 450 nt. It was considered highly conserved (85.55%), low G+C content (41%), and high genetic similarities (92.47 to 100%). Phylogenetic analysis delineates isolates into two large groups, i.e. the Asian group (East Asia and South-east Asia) and the South Pacific group (South Asia, Africa and the Pacific). The findings of this study are usefull for broader applicability of further banana breeding program particularly for mitigation, selection and evaluation of banana with BBTV resistance

Pengaruh Umur Kematian Tanaman Sumber Inokulum Banana Bunchy Top Virus Terhadap Efisiensi Penularannya

BBTV is one of the important diseases in banana plants, the transmission of BBTV can be carried out by Pentalonia nigronervosa. In some banana plantations infected plants are usually cut down because they are considered unable to produce optimal production. The felled plants will then be placed around healthy plantations, this situation is thought to have the potential as a place for P. nigronervosa to temporarily live and spread the virus to other healthy plants. This study aims to determine the ability of dead plants that host P. nigronervosa to re-transmit the virus to healthy plants. The study was conducted using a Randomized Block Design (RAK) with six treatments on the day of death of infected plants, namely, 0, 5, 10, 15, 20, and 25 days, with five replications. From the results of the study, it was found that plants infected by BBTV still had potential to transmit the virus to healthy plants through the P. nigronervosa. Transmission of BBTV from dead plants on the fifth day resulted in the highest average of BBTV infection. The incubation period of virus in plants ranged from 30-53 days after inoculation. From this research, it is hoped that farmers will pay more attention to thoroughly eradicate banana plants infected by BBTV, removed all plant and suckers thoroughly together with their corms

First Report of Banana Bunchy Top Disease on Banana in Bengkulu.

Banana is a horticulture crop that has economic value and is widely cultivated in tropical countries. Banana production in Bengkulu province reached 259,748 quintals, then durian (110,387 quintals), tangerines (94,396 quintals) (BPS 2015). Banana bunchy top disease caused by Banana bunchy top virus (BBTV) infection is considered the most crucial virus disease affecting yield losses of a banana plantation in Asia, Africa, and the South Pacific. However, the incidence and molecular characters of BBTV has never been reported in Bengkulu. This research aims to characterize symptom variations, disease incidence, and disease severity of BBTV infection in Bengkulu and virus detection using molecular methods by polymerase chain reaction (PCR). Disease incidence of BBTV was measured based on field symptoms. The disease survey was conducted in Bengkulu city, Bengkulu Utara district, and Rejang Lebong district. The study showed that the incidence of BBTV in Bengkulu City, Bengkulu Utara, and Rejang Lebong ranged from 0% to 100%. The most common symptoms observed in the field involved vein clearing, upturned leaf, chlorotic, and ragged margins, reducing petiole length, distance, lamina width, and stunting. Banana crops that are infected with BBTV in the vegetative phase will not produce fruit. In contrast, viral infection in the generative phase causes the formation of stunted fruit that is not suitable for harvesting. Thus, the potential loss of yield due to stunted disease can reach 100%. This study's results are the first reports of BBTV infection in banana crops in Bengkulu. Disease diagnosis will form the basis of disease control strategies in banana crops

Identification of a nanovirus-alphasatellite complex in Sophora alopecuroides

Viruses in the genus Nanovirus of the family Nanoviridae generally have eight individually encapsidated circular genome components and have been predominantly found infecting Fabaceae plants in Europe, Australia, Africa and Asia. For over a decade Sophora alopecuroides L. (Fabaceae) plants have been observed across Iran displaying dwarfing, yellowing, stunted leaves and yellow vein banding. Using a high-throughput sequencing approach, sequences were identified within one such plant that had similarities to nanovirus genome components. From this plant, the nanovirus-like molecules DNA-R (n\ua0=\ua04), DNA-C (n\ua0=\ua02), DNA-S (n\ua0=\ua01), DNA-M (n\ua0=\ua01), DNA-N (n\ua0=\ua01), DNA-U1 (n\ua0=\ua01), DNA-U2 (n\ua0=\ua01) and DNA-U4 (n\ua0=\ua01) were amplified, cloned and sequenced. Other than for the DNA-R, these components share less than 71% identity with those of other known nanoviruses. The four DNA-R molecules were highly diverse, sharing only 65–71% identity with each other and 64–86% identity with those of other nanoviruses. In the S. alopecuroides plant 14 molecules sharing 57.7–84.6% identity with previously determined sequences of nanovirus-associated alphasatellites were also identified. Given the research activity in the nanovirus field during the last five years coupled with high-throughput sequence technologies, many more diverse nanoviruses and nanovirus-associated satellites are likely to be identified

Independent modulation of individual genomic component transcription and a cis-acting element related to high transcriptional activity in a multipartite DNA virus

Background: The genome of Banana bunchy top virus (BBTV) consists of at least six circular, single-stranded DNA components of 1kb in length. Some BBTV isolates may also carry satellite DNA molecules that are not essential for BBTV infection. The relation between multipartite DNA virus replication and their transcriptional levels and the underlying mechanism remain unclear. Results: To understand the coordinated replication and transcription of the multiple genomic components, the absolute amounts of each BBTV DNA component were measured by real-time PCR (qPCR), and their transcriptional levels were determined by RNAseq and reverse transcription-qPCR (qRT-PCR). Significant differences were found in the absolute amounts of individual BBTV genomic components. Transcriptional levels of each BBTV genomic component obtained from the RNAseq data matched closely to those obtained from qRT-PCR, but did not correspond to the absolute amount of each DNA component. The ratio of transcript over DNA copies ranged from 46.21 to 1059.44%, which was possibly regulated by the promoter region in the intergenic region of each component. To further determine this speculation, the promoter region of the DNA-S, -M or -N was constructed to the upstream of green fluorescent protein (GFP) gene for transient expression by agrobacterium-mediated transformation method. The qRT-PCR showed the highest transcriptional activity was promoted by DNA-N promoter, about 386.58% activity comparing with CaMV 35S promoter. Confocal microscopy observation showed that the intensity of green fluorescence was corresponding to that of qRT-PCR. Conclusions: Our data clearly showed that BBTV was able to control the transcriptional level of each DNA component independently by through the promoter sequences in the intergenic region. Moreover, a cis-acting element from DNA-N component had a high transcriptional activity.National Natural Science Foundation of China [31401709]; Hainan Provincial Natural Science Foundation [20153130]; Central Public-interest Scientific Institution Basal Research Fund for Chinese Academy of Tropical Agricultural Sciences [19CXTD-33]; Young Elite Scientists Sponsorship Program, CSTC [CSTC-QN201704]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]