S02 - Session O1 - Conservation and sanitation of tropical genetic resources: a challenge for food security and germplasms exchange

Authors: Marie Umber *, Yoana Faure, Suzia Gélabale, Rose-Marie Gomez, Nilda Paulo de la Réberdière, Michel Roux-Cuvelier

The preservation of genetic resources is challenging facing the climate change and health emergencies. The French Biological Resource Centers (BRCs) have the challenge of conserving this biological material in order to provide research institutes with tools for breeding and the discovery of new processes, as well as farmers for the diversification of their production. The CRB Tropical Plants (CRB-PT) five collections of plants of great importance for the tropical regions, banana, mango, pineapple, sugarcane and yam, as well as the herbarium of the Lesser Antilles. Two of these collections, pineapple and yam, are facing important sanitary problems mainly due to viral diseases. The pineapple collection, preserved in the field, is affected by the Wilt disease, transmitted by mealy bugs, which decimates pineapple plantations in Guadeloupe and Martinique following the cessation of insecticide use. This disease is due to a viral cocktail composed of about ten different viruses, mostly discovered by NGS and whose role in the etiology of the disease is not well defined. Concerning the yam collection, mainly kept in in vitro culture, 95% of the accessions are contaminated by at least 1 virus, mostly in co-infection. There are about twenty viral species identified on yam, and some of them are at the origin of the disappearance of some yam species in the production plots in the West Indies, such as the species Dioscorea trifida, which is endemic to the Amazonian basin. The identification of the virome of these virus-susceptible plants is an essential step to control them, and this is being done on pineapple germplasm and yam. Sanitation techniques have been developed on both plants in order to generate healthy plants, free of all viral diseases. They are based on in vitro culture techniques, such as thermotherapy and meristem culture. Their implementation requires the development of reliable and sensitive diagnostic tools in order to verify their efficiency and to ensure the production of virus-free plants. However, if these techniques have shown their usefulness, their efficiency remains low, and it is important to develop other techniques on these two problematic plants, such as cryotherapy.