Gene Banks Pay Big Dividends to Agriculture, the Environment, and Human Welfare R
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Community Page Gene Banks Pay Big Dividends to Agriculture, the Environment, and Human Welfare R. C. Johnson early a century after the pioneering American Napple tree purveyor Johnny Appleseed traveled from town to town planting nurseries in the Midwestern United States, Frans Nicholas Meijer left his Netherlands home to pursue a similar vocation as an “agricultural explorer” for the US Department of Agriculture. Over the course of his career, Meijer, who changed his name to Frank Meyer after reaching the New World, helped introduce over 2,500 foreign plants from Europe, Russia, and China, including the lemon that would bear his name. Starting with his first expedition for Asian plants in 1905, Meyer would encounter isolation, physical discomfort, disease, robbers, and revolutionaries in his quest to collect useful plants. Although some of Meyer’s collections are still used today, only a few are conserved in their original doi:10.1371/journal.pbio.0060148.g001 form. They, along with countless other Figure 1. Collecting Accessions collections from the early 20th century, Walter Kaiser collects taper-tip onion (Allium acuminatum) along the Snake River in Idaho in 2005. disappeared because there was no long- Collections were made across a broad area of Western rangeland to strengthen the WRPIS Allium term system for conservation. To rectify collection and for research to determine taper-tip onion adaptation zones needed for successful revegetation. this problem, Congress established a system of repositories after World and maintain germplasm is ongoing genetic uniformity and dependence on War II to maintain and distribute and urgent. Since agriculture’s just a few crops. plant genetic resources. This resource beginnings about 10,000 years ago, According to the World Conservation has now grown into the National approximately 7,000 of Earth’s Union, one in every eight plant species Plant Germplasm System (NPGS; 300,000 plant species have been used in the world, and one in three in the http://www.csrees.usda.gov/nea/ as crops. The Food and Agriculture US, is threatened with extinction, plants/in_focus/pbgg_if_npgs.html) Organization estimates that today only resulting largely from the development and consists of 26 repositories with 150 plant species are under extensive approximately half a million individual global cultivation, with 12 crop species Citation: Johnson RC (2008) Gene banks pay big collections. The NPGS functions to dividends to agriculture, the environment, and providing 80% of the world’s food. human welfare. PLoS Biol 6(6): e148. doi:10.1371/ maintain agricultural biodiversity and Although modern agriculture feeds journal.pbio.0060148 ensure the preservation of the genetic more people on less land than ever resources needed for food security and This is an open-access article distributed under the before, it also results in high genetic terms of the Creative Commons Public Domain environmental restoration. uniformity by planting large areas declaration, which stipulates that, once placed in the of the same species with genetically public domain, this work may be freely reproduced, Reducing Genetic Vulnerability distributed, transmitted, modified, built upon, or similar cultivars, making entire crops otherwise used by anyone for any lawful purpose. with Germplasm highly vulnerable to disease, drought, Abbreviations: ICRISAT, International Crops As crop genetic resources continue to and insect infestation. The Irish potato Research Institute for Semi-Arid Tropics; NCGPR, erode worldwide, the need to acquire famine of the mid-1800s, which claimed National Center for Genetic Resources Preservation; an estimated 1.5 million lives, and the NPGS, National Plants Germplasm System; WRPIS, Western Regional Plant Introduction Station heavy losses to the 1970 US corn crop The Community Page is a forum for organizations from southern corn leaf blight, costing R. C. Johnson is with the Agricultural Research Service, United States Department of Agriculture, and societies to highlight their efforts to enhance the an estimated US$1 billion, provide Pullman, Washington, United States of America. E- dissemination and value of scientific knowledge. dramatic illustrations of the risks of mail: [email protected] PLoS Biology | www.plosbiology.org 1152 June 2008 | Volume 6 | Issue 6 | e148 of rural land and invasion of alien species. Many of these threatened plant species may harbor unknown attributes that could benefit agriculture or the environment. With climate change, some plant populations may disappear completely. Expanding conservation to preserve seeds and genetic resources through gene banks has become critically important, yet it is only one component of a larger conservation plan aimed at preserving plants in situ on farms, in reserves, and in their native habitats. Though the challenge is great, there is more effort and interest than ever. As part of the NPGS, the Western Regional Plant Introduction Station (WRPIS; http://www. ars.usda.gov/main/site_main. htm?modecode=53481500) in Pullman, Washington, acquires, maintains, conserves, evaluates, and distributes plant genetic resources needed to doi:10.1371/journal.pbio.0060148.g002 improve crops, develop new crops, Figure 2. Regenerating Seeds and provide plant material for Accessions must be regenerated when the quality or quantity of seed is low. Here Marie Pavelka environmental restoration. Accessions and Terri LeClaire (foreground) plant leek accessions for seed regeneration. Each plot will be covered with a screen cage to prevent crossing with other accessions, and bluebottle flies will be (distinct, uniquely identified samples introduced into the cages as pollinators. of seeds or plants maintained as part of a germplasm collection) are back-up of accessions is provided at specimens from diverse regions and acquired through field exploration −18 °C or in liquid nitrogen at the climates with new attributes, paving and exchanges with other gene banks National Center for Genetic Resources the way for the creation of innovative and organizations (see Figure 1). To Preservation (NCGPR; http://www.ars. agricultural tools. Useful germplasm ensure that collections are free of usda.gov/Main/docs.htm?docid=8071) is “where one finds it,” and screening invasive weeds and pests, accessions in Fort Collins, Colorado. Each procedures range from traditional entering the US are inspected by the year the WRPIS fills approximately field evaluation trails to advanced Animal and Plant Health Inspection 1,500 seed orders, sending out about DNA marker technology. Yet the time Service. Seeds from new collections 20,000 seed packets to researchers between collection and utilization are cleaned, their taxonomy verified, worldwide. Much of the screening is typically years or even decades. tested for viability, and annotated and development for disease, insect, When the major sugar beet disease with population and ecological and abiotic stress resistance is rhizomania was found in North information from collection locations. done through the germplasm user America in the 1980s, resistance These “passport data” are available community; that is, those researchers depended on a single gene, Rz1. to all on the Germplasm Resources requesting germplasm, but scientists Understanding that single gene Information Network (http://www.ars- at the WRPIS also do this work, often resistance would be vulnerable to new grin.gov/npgs/). When the quantity in cooperation with off-station users. virus strains, plant breeders developed or quality of seeds is low, an increase The grasses are the largest collection other sources of resistance. These or grow-out is needed to make seeds with more than 18,000 accessions and included resistance in a sugar beet available for distribution (see Figure 2). 107 genera. Other major collections from Turkey collected in 1952 and in This is done using growth chambers, include beans (more than 15,000 an accession from Denmark collected greenhouses, and field facilities under accessions with 50 taxa represented), in 1985, both in the WRPIS collection. strict guidelines to preserve the genetic alfalfa (more than 7,500 accessions By 2002, the rhizomania virus had integrity of accessions. Each year, more with 78 taxa), peas (more than 4,000 overcome the Rz1 resistance, and than 1,600 accessions and 100,000 accessions with 12 taxa), and beets these new forms of resistance are now plants are grown for seed increase at (more than 2,500 accessions with 16 being used as the next line of defense the WRPIS. taxa). against the disease. This type of “race The WRPIS collection of for genes,” the need to stay ahead of approximately 80,000 accessions is an Mining Gene Banks for Novel new and variant forms of pests, relies “active collection” maintained under Attributes on the continual supply of germplasm intermediate-term storage at 4 °C to Plant breeders are still finding useful from gene banks and new collections. facilitate management and distribution genes within these collections, and Recently, a new type of insect- (see Figure 3). Long-term, security plant explorers are still uncovering resistance for grasses was developed PLoS Biology | www.plosbiology.org 1153 June 2008 | Volume 6 | Issue 6 | e148 using WRPIS collections acquired from Morocco in the 1990s. These collections were examined for fungal endophytes, which live inside plants and produce alkaloids that can be toxic to grazing animals and insects. In this mutually beneficial living arrangement, the fungus receives a protected living