Fundecitrus - Brazil / IBMCP - Spain
Leandro A. Peña Garcia had PhD in Biological Sciences from the Autonomous University of Madrid. From 1993 until January 2014 he has been research leader at the Center of Plant Protection and Biotechnology of the Valencian Institute of Agricultural Research (IVIA), from which is in temporary leave. He is specialized in plant breeding through biotechnology and has over 20 years experience on working in citrus biotechnology. His current research projects include rapid induction of flowering and consequent reduction in the juvenile period, pathogen resistance (Huanglongbing, Canker, Black spot, Gummosis, Tristeza) and pest unattractiveness (Medfly), modulation of tree size and architecture, modifying terpene metabolism and composition of carotenoids and flavonoids in the fruit to improve nutritional and organoleptic characteristics. He has published more than 100 papers (corresponding author in about 90%) in journals including Nature Biotech., New Phytol. or Plant Phys. and book chapters on these topics. Author of 5 international patents. He has participated in numerous evaluation committees of Spanish national and international agencies. He has been consultant of the biotechnology company Alellyx, the National Academy of Sciences USA, the Florida Citrus Production Advisory Board, and Fundecitrus (Fundo de Defesa da Citricultura). Currently he is working at Fundecitrus (Araraquara, Sao Paulo, Brazil) and the Institute of Plant Molecular and Cellular Biology (IBMCP) of the CSIC and the Polytechnic University (UPV) at Valencia.
Summary of lecture
Transgenic strategies to control citrus Huanglongbing
The global citrus industry is seriously threatened today by Huanglongbing (HLB). While aggressive insecticide treatments and symptomatic tree removal are essential at this time to mitigate the effects of the disease and are highly recommended measures, it is practically impossible the long-term coexistence between both a profitable, environmentally respectful citrus industry and the endemic presence of HLB.
In the last 15 years, the most aggressive HLB (induced by the bacterium Candidatus Liberibacter asiaticus, transmitted by the psyllid insect Diaphorina citri) has been spread quickly across almost the entire American continent and the Arabian Peninsula. In America, HLB hits and still currently threatening some of the most important world citricultures. Although the African HLB (induced by the bacterium Candidatus Liberibacter africanus, transmitted by the psyllid insect Trioza erytrae) is not so aggressive as the Asian, it is also an important disease. Furthermore, under appropriate conditions, T. erytrae can vector Candidatus Liberibacter asiaticus.
In this case, palliative and/or curative treatments did not help to keep productive citrus orchards. The only effective, long-term measure to cope with HLB would be generating plants resistant/tolerant to the bacteria and/or their insect vectors. Despite many studies, it has not been found in the citrus germplasm any source of genetic resistance to the disease. Therefore, it is impossible to get resistance by generating new genotypes through classical breeding. Furthermore, the complex genetic and reproductive characteristics of citrus types would make this extraordinarily difficult if a source of resistance would be found in sexually compatible genotypes in the future.
We believe the only lasting and sustainable medium-term way for resistance to HLB is to incorporate genetic resistance through biotechnology into citrus varieties and rootstocks. In citrus, the only way to improve well-known genotypes without altering their genetic background is genetic engineering, namely the incorporation of unique characters into elite varieties and/or rootstocks. We present here the transgenic strategies under testing and the most recent results of the efforts made in this regard.