Virus-Indexing Technology for Production of Quality Banana Planting Material: A Boon to the Tissue-Culture Industry and Banana Growers in India

Abstract

Banana and plantain (Musa spp.) are the most important fruit crop in India and play a major role in the livelihood of millions of resource-poor small farmers. Use of quality planting material is very important for increasing productivity. Though conventional suckers are still the primary planting material, use of tissueculture plants has increased because of their advantages, like more uniform bunches with even maturity and increased yield. However, banana viral pathogens, which are economically important in India, can be inadvertently spread through tissue-culture plants. In order to control the spread of the viruses, virus-indexing techniques were developed at the National Research Centre for Banana, Tiruchirapalli for early detection in mother plants and tissue-culture plants used for mass propagation. Polymerase chain reaction (PCR), reverse transcriptase PCR (RT-PCR), nonradioactive probe-based nucleic acid spot hybridisation (NASH) and enzyme-linked immune-sorbent assay (ELISA) based techniques were developed and validated for routine testing. PCR and NASH tests are being done for detection of Banana bunchy top virus (BBTV) and Banana streak Mysore virus (BSMysV). RT-PCR and ELISA tests are being done for the detection of Banana bract mosaic virus (BBrMV) and Cucumber mosaic virus (CMV). Based on the work done at the centre, the Department of Biotechnology (DBT), Government of India, has accredited the Molecular Virology lab for testing for banana viruses in the country. In total, 15,850 tissue-culture and mother-plant samples were tested against viruses. The percentage of positive plants for BBTV, BSMysV, CMV and BBrMV were 3.83, 2.85, 17.3 and 0.95% respectively. Indexing was done mostly for the cultivars 'Grande Naine' (AAA, Cavendish subgroup), 'Robusta' (AAA, Cavendish subgroup) and 'Hill Banana' (syn. 'Virupakshi', AAB, Pome subgroup). Around 25 tissue-culture banana commercial laboratories are undertaking the services of virus testing. Our laboratory has also developed polyclonal antisera for CMV and BBrMV through recombinant DNA technology, which is currently being validated for ELISA-based testing.

A method for generating virus-free cassava plants to combat viral disease epidemics in Africa

“…Tolerant and resistant plants were cleaned in the first cycle, which took only about 8–10 months. Cleaning of vegetatively-propagated crops like cassava in this study and bananas, potatoes, sweetpotatoes, sugarcane and other crops by others has been done before [21,22,24]. However, cleaning and germplasm exchange at regional level is the first of its kind to our knowledge for any vegetatively-propagated crop and sets an example to follow for other crops for better disease control, improved yields and food securities.…”

“…Such protocols are also adapted by the regulatory bodies in Ethiopia and Tanzania for generating certified seeds of sweetpotatoes [22]. In Africa and elsewhere, virus-free planting materials have been developed for several other crops including banana, citrus and cassava for providing healthy planting material to farmers for increased yields [20,23,24]. In this paper, we describe the use of such virus-indexing protocols at a regional level for cleaning cassava from five eastern and southern African countries of Kenya, Tanzania, Uganda, Malawi and Mozambique in the project “Cassava varieties and Clean seed to Combat CBSD and CMD project (5CP)” for providing virus-free planting material to the affected farmers.

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Badnaviruses: The Current Global Scenario

“…For banana plants that contain ‘B’ genome and harbor both episomal and activatable endogenous BSVs (BSOLV, BSIMV, and BSGFV), use of RCA and PCR are needed, while for other banana plants, only RCA could be used to distinguish between endogenous and free viral genomes. Development of real-time PCR for the rapid detection of episomal BSOLVand BSMYV was reported [ 100 , 101 , 102 , 103 ]. Multiplex immunocapture PCR (M-IC-PCR) and rolling circle amplification (RCA) have been developed for the detection of BSV genomes [ 72 , 73 , 104 ].…”

Recombinant Coat Protein of Banana Bract Mosaic Virus as a Potential Antigen for Serological Detection of the Virus

“…The period of latency of the virus to showcase symptoms in the infected plants is not only a threat to the domestic market especially where it is vegetatively propagated but also to international germplasm exchange [20]. The tissue culture planting materials that look prima facie healthy, especially have to be indexed for the presence of this virus [21]. Hence, early detection is the key for controlling the disease along with providing virus indexed high quality planting materials to the farmers until a resistant variety is identified and used for breeding [1].…”