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Sixteen yeast isolates identified as belonging to the genus Sugiyamaella were studied in relation to D-xylose fermentation, xylitol production, and xylanase activities. The yeasts were recovered from rotting wood and sugarcane bagasse samples in different Brazilian regions. Sequence analyses of the internal transcribed spacer (ITS) region and the D1/D2 domains of large subunit rRNA gene showed that these isolates belong to seven new species. The species are described here as Sugiyamaella ayubii f.a., sp. nov. (UFMG-CM-Y607 = CBS 14108), Sugiyamaella bahiana f.a., sp. nov. (UFMG-CM-Y304 = CBS 13474), Sugiyamaella bonitensis f.a., sp. nov. (UFMG-CM-Y608 = CBS 14270), Sugiyamaella carassensis f.a., sp. nov. (UFMG-CM-Y606 = CBS 14107), Sugiyamaella ligni f.a., sp. nov. (UFMG-CM-Y295 = CBS 13482), Sugiyamaella valenteae f.a., sp. nov. (UFMG-CM-Y609 = CBS 14109) and Sugiyamaella xylolytica f.a., sp. nov. (UFMG-CM-Y348 = CBS 13493). Strains of the described species S. boreocaroliniensis, S. lignohabitans, S. novakii and S. xylanicola, isolated from rotting wood of Brazilian ecosystems, were also compared for traits relevant to xylose metabolism. S. valenteae sp. nov., S. xylolytica sp. nov., S. bahiana sp. nov., S. bonitensis sp. nov., S. boreocarolinensis, S. lignohabitans and S. xylanicola were able to ferment D-xylose to ethanol. Xylitol production was observed for all Sugiyamaella species studied, except for S. ayubii sp. nov. All species studied showed xylanolytic activity, with S. xylanicola, S. lignohabitans and S. valenteae sp. nov. having the highest values. Our results suggest these Sugiyamaella species have good potential for biotechnological applications.

Five ascosporogenous yeast strains related to the genus Kazachstania were isolated. Two strains (CLIB 1764T and CLIB 1780) were isolated from French sourdoughs; three others (UFMG-CM-Y273T, UFMG-CM-Y451 and UFMG-CM-Y452) were from rotting wood in Brazil. The sequences of the French and Brazilian strains differed by one and three substitutions, respectively, in the D1/D2 large subunit (LSU) rRNA gene and the internal transcribed spacer (ITS). The D1/D2 LSU rRNA sequence of these strains differed by 0.5 and 0.7 % from Kazachstania exigua, but their ITS sequences diverged by 8.1 and 8.3 %, respectively, from that of the closest described species Kazachstania barnettii. Analysis of protein coding sequences of RPB1, RPB2 and EF-1α distinguished the French from the Brazilian strains, with respectively 3.3, 6 and 11.7 % substitutions. Two novel species are described to accommodate these newly isolated strains: Kazachstania saulgeensis sp. nov. (type strain CLIB 1764T=CBS 14374T) and Kazachstania serrabonitensis sp. nov. (type strain UFMG-CM-Y273T=CLIB 1783T=CBS 14236T). Further analysis of culture collections revealed a strain previously assigned to the K. exigua species, but having 3.8 % difference (22 substitutions and 2 indels) in its ITS with respect to K. exigua. Hence, we describe a new taxon, Kazachstania australis sp. nov. (type strain CLIB 162T=CBS 2141T), to accommodate this strain. Finally, Candida humilis and Candida pseudohumilis are reassigned to the genus Kazachstania as new combinations. On the basis of sequence analysis, we also propose that Candida milleri and Kazachstania humilis comb. nov. are conspecific.

Endophytic fungi live inside plants as symbionts for at least one period of their life cycle. They play an important role in plant defence and could be promising sources of valuable natural bioactive products. The present study aimed to select endophytic fungi antagonistic to Microcyclus ulei, the agent of South American Leaf Blight (SALB) responsible for the weak development of rubber plantations in Latin America. Endophytic fungi were isolated from leaves of three cultivars (FX3864, CDC312, MDF180) of Hevea brasiliensis (the rubber tree) with distinct resistance levels to the attack by Microcyclus ulei. Leaf samples were collected from a 5,000 ha area of the Michelin plantations (Igrapiúna, Bahia, Brazil). A total of 435 colonies of endophytic fungi were isolated, purified, and preserved in sterilized distilled water. Lyophilized culture filtrates obtained from 88 fungal isolates, grown in liquid malt extract medium, were tested in vitro at concentrations of 50% and 12.5% for their inhibitory potential against the germination of M. ulei PMB26 conidia. Thirteen filtered cultures of endophytic fungi that presented inhibitory activity above 80% (at the concentration 12.5%) were characterized taxonomically by sequencing the ITS regions of rDNA, revealing the following taxa: Fusarium sp., Gibberella sp., Glomerella cingulata, Microsphaeropsis sp., Myrothecium sp., Pestalotiopsis sp. and Phomopsis sp. Three taxa were detected only in the resistant cultivars: Microsphaeropsis sp., and Pestalotiopsis sp. in MDF180, and Myrothecium sp. in CDC312. The present work constitutes the first study showing inhibitory activity of rubber tree endophytic fungi on Microcyclus ulei. These results provide an encouraging basis for the identification of new bioactive molecules for an effective control of South American leaf blight.