DIVERSITY AND PATHOGENICITY OF Botryosphaeriaceae SPECIES ASSOCIATED WITH STEMS ROT OF SWEET POTATO IN BRAZIL

all lineages of plants without causing evidence of disease during some stage of their life cycle. Therefore, leaves and stems of several plants may represent hotspots of the fungal endophytes diversity. The Caatinga, a tropical dry forest in Brazil, presents a great heterogeneous diversity and endemic plant species, such as Poincianella pyramidalis, a medicinal plant popularly known in Brazil as catingueira. Plants from semiarid regions survive under stressful conditions, often associated with lack of water resources, high soil salinity and radiation effects, however, there are ideas about the involvement of endophytes in protecting plants against climate adversities. The aim of this study was to verify the diversity of endophytic fungi associated to branches of P. pyramidalis in three successional areas of the Caatinga forest. The plant material was collected in three ecological succession areas of the Caatinga (initial, intermediate and preserved) at Fazenda Tamanduá in the municipality of Santa Terezinha, Paraíba, Brazil. The branches were disinfested superficially using alcohol 70%, sodium hypochlorite (2-2.5% active chlorine), alcohol 70%, and three successive washes in distilled and sterilized water. The fragments were transferred to Petri dishes containing Potato-Dextrose-Agar medium supplemented with antibiotic to reduce bacterial growth. The plates were incubated at 28 °C for up to 30 days. Macro and micro morphological characteristics were used for the morphological endophytes identification. For the study of molecular phylogeny, the DNA was extracted from the fungal biomass and part of the ITS rDNA region was studied. The amplification products were sequenced and the sequences obtained compared to similar sequences in the GenBank database using the BLASTn tool. The results showed a total of 61 endophytes distributed in 16 genera. Members of Diaporthe were the most isolated endophytes, followed by Phoma and Rhytidhysteron. In the areas of initial, intermediate and preserved ecological succession, 20, 13 and 28 endophytes were isolated, respectively. The Shannon-Wiener diversity index showed that the initial succession area was the most diverse. The Pielou Equitability and the Simpson index also demonstrated that the initial succession area was the most abundant. This study evaluated for the first time the diversity of endophytic fungi from branches of the medicinal plant P. pyramidalis present in Caatinga forest in different stages of ecological succession. Sustainable management of natural areas of the Caatinga is necessary for the conservation and maintenance of plant fungal endophytes diversity in this environment.