DNA Barcoding Case Studies

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Scope

The Free State is the only province in South Africa bordered by six of the nine other provinces. Of the ±23 000 plant species in South Africa, approx. 3000 occur in the Free State. Today over one thousand plant species are traded for medicinal purposes nationwide. The number of such South African species originating in the Free State, and the number of ethnomedicinals trafficked through this central province is unknown. The main objective of the project is to generate a barcode database for the entire Free State flora, sampling at least three specimens per taxon. This database will be used to assist in identifying ethnomedicinal species based on plant parts (e.g. roots, bark) in trade.

Purpose

Indigenous natural plant products have been traded in the Southern African region for centuries. Over the past few years there has been considerable growth in the South African medicinal plant industry, which forms an important part of the country’s hidden economy, providing some 30 000 jobs. It is estimated that, nationally, between 75% and 80% of the population consult some 300 000 traditional medical practitioners. In South Africa the medicinal trade in plants receives little or no formal recognition by the State; in consequence, certain popularly-traded species have been over-exploited and are threatened with extinction in the wild. Given that the Free State is South Africa’s third-largest province (10.6% total land area), it is of concern that no research has previously been conducted on the regional ethnomedicinal trade. In view of its centrality and range of plant biomes, its contribution to the medicinal trade is likely substantial. Barcoding the entire flora of the Free State will improve the management and understanding of biodiversity by making herbarium material and DNA barcodes available to the scientific community. The project also aims at informing nature conservation authorities about both qualitative and quantitative aspects of the trade, so enabling informed decision making in respect of plants important to human health, and ecosystem functioning.

Background

The Free State Province is the granary of South Africa: 32 000 square kilometres of land are cultivated for cereals. It is also the country’s leader in the production of bio-fuels. Mining is the province’s main employer, with 12 goldmines producing 30% of South Africa’s gold output. Migrant labour servicing this industry will require access to familiar ethnomedicinal plants, a feature known to influence inter-provincial trade in neighbouring Gauteng.   Seventeen veld types are represented in the Province, of which the temperate grasslands and the arid Nama Karoo are the most characteristic. These grasslands stretch from the dry southwest to the moist sandstone mountains in the northeast. As a result of mining and agricultural activities the grasslands are under serious threat.

 This will be the first barcoding initiative in the Free State and the second one in the country. Currently Michelle van der Bank and Vincent Savolainen are running a similar initiative for the flora of the Kruger National Park, using barcodes to identify the different plant species.

Logistics

This project will be chaired by Dr PC Zietsman (Department Botany, National Museum) and assisted by Prof. G Smith (South African National Biodiversity Institute, SANBI), Prof. N Crouch (Ethnobotany Unit, SANBI), Dr B Visser (University of the Free State) and Ms Hester Delport (Department Botany, National Museum). The plant material used for the barcoding will either be obtained from herbarium specimens or collected during the course of the project. All molecular analyses of the collected plants will be done in the laboratory of Dr Visser.  The internationally accepted barcoding gene for animals, cytochrome c oxidase 1 (COI), is not effective for plant barcoding. Instead two chloroplast gene sequences, MatK and psbA-trnH, will be targeted. Their discriminatory value has already been established in the Kruger National Park barcoding project. A third gene will also be included if proven useful. Different plant tissues (eg fresh, dried and degraded) will be initially tested to ensure efficient DNA extraction and sequencing.  Comparisons between different populations of the same species will also be done in an effort to determine whether geographical factors have any influence on the barcode. The sequence data generated will be included in appropriate databases to establish the barcode for the Free State flora

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