Espécies de Lasiodiplodia associadas à morte descendente da videira no Nordeste do Brasil e diversidade genética de Lasiodiplodia theobromae

• Autor(a) principal: RÊGO, Tamiris Joana dos Santos
• Data de Publicação: 2018
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRPE
• Texto Completo: http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/7834
• topic: Botryosphaeriaceae; Lasiodiplodia; Morte descendente; Videira; FITOSSANIDADE::FITOPATOLOGIA

Botryosphaeria dieback is a disease caused by species of Botryosphaeriaceae, and currently considered one of the main diseases of the stem of the grapevine, responsible for serious damage to the culture in the northeastern of Brazil and in the world. In view of the increased importance of this disease, and the large number of pathogens involved in the infection including Lasiodiplodia theobromae an important crop and post-harvest pathogen, this study aimed: (i) identify species of Lasiodiplodia associated with the downward death of the vine in areas of tropical climate with dry summer and semi-arid climate in northeastern of Brazil, and (ii) know the genetic diversity of Lasiodiplodia theobromae of Brazil and Mexico. A total of 94 isolates from Lasiodiplodia were identified from DNA sequence data (tef1-α e ITS), being found six species: L. crassispora, L. euphorbicola, L. hormozganensis, L. iraniensis, L. pseudotheobromae e L. theobromae, and two hybrids: L. xbrasiliense e xlaeliocatlelyae. Lasiodiplodia theobromae and L. pseudotheobromae were the most prevalent species in this study. All species were pathogenic to the grapevine with significant differences in disease severity. The species L. hormozganensis, L. iraniensis, and L. euphorbicola were the most aggressive, and L. theobromae, L. pseudotheobromae, and L. xbrasiliense were the least aggressives. The diversity study of 117 isolates of L. theobromae from Brazil (n=100) and Mexico (n=17) using simple repeat markers (SSR) revealed low genetic diversity among populations and the existence of two genetic groups. All Mexican isolates were grouped with Brazilian isolates suggesting a low level of differentiation between these populations. Furthermore, no evident host or climate-based population differentiation was observed for L. theobromae in northeastern Brazil. The populations studied were mostly clonal, but additional studies are needed to better understand the mode of reproduction of the pathogen. As populations of L. theobromae present low diversity in northeastern Brazil it is likely that the development of resistant cultivars is a good strategy of management.