Plant & Animal Genomes XIII Conference Plant & Animal Genomes XIII ConferenceJanuary 15-19, 2005
Town & Country Convention Center
San Diego, CA
Raquel L. Boscariol , Luciana H. Figueiredo , Gustavo Astua-Monge , Marcos A. Machado
The long periods of drought in several regions of Brazil are among the most important limiting factors for citrus production. This problem has been traditionally overcome by the use of a drought-tolerant rootstock, 'Rangpur' lime, which has made possible citrus production under limiting conditions. However, this rootstock is proven to be highly susceptible to "Citrus Sudden Death", a new disease that is causing severe losses to the Brazilian citrus industry. In order to improve this scenario, it is necessary to gain a better understanding of the mechanisms involved in the response of citrus plants to water stress. The Centro APTA Citros Sylvio Moreira has already generated more than 240,000 EST sequences from citrus plants exposed to different conditions. We are using this information to search for genes potentially associated with drought tolerance. The main targets included genes associated with proline synthesis, water channels formation (aquaporins), response to abscisic acid (ABA), and those genes that code for proteins involved with cellular dehydration like the late embryogenesis abundant protein (Lea) and the heat shock proteins (HSP). So far, we have found genes encoding proteins with high homology to the CuCOR19 protein (LEA family), DREB1 and DREB2 (LEA family), HSP class I (HSP family), gamma-OAT (proline family), P5CS (proline family), PIP1 and PIP2 (aquaporins), bZIP (DNA binding protein), ABA1, and ABA2. Results on tissue specificity and in silico expression profiles are presented as well as their potential incorporation into our citrus transformation program.