Taxogenomic analyses of Starmerella gilliamiae f.a, sp. nov. and Starmerella monicapupoae f.a., sp. nov., two novel species isolated from plant substrates and insects

Four yeast isolates collected from flowers from different ecosystems in Brazil, one from fruit of Nothofagus alpina in Argentina, three from flowers of Neltuma chilensis in Chile and one obtained from the proventriculus of a female bumblebee in Canada were demonstred, by analysis of the sequences of the internal transcribed spacer (ITS) region and D1/D2 domains of the large subunit rRNA gene, to represent two novel species of the genus Starmerella. These species are described here as Starmerella gilliamiae f.a, sp. nov. (CBS 16166T; Mycobank MB 851206) and Starmerella monicapupoae f.a., sp. nov. (PYCC 8997T; Mycobank MB 851207). The results of a phylogenomic analysis using 1037 single-copy orthogroups indicated that S. gilliamiae is a member of a subclade that contains Starmerella opuntiae, Starmerella aceti and Starmerella apicola. The results also indicated that S. monicapupoae is phylogenetically related to Starmerella riodocensis. The two isolates of S. monicapupoae were obtained from flowers in Brazil and were probably vectored by insects that visit these substrates. Starmerella gilliamiae has a wide geographical distribution having been isolated in flowers from Brazil and Chile, fruit from Argentina and a bumblebee from Canada.

Wickerhamiella martinezcruziae f. a., sp. nov., a yeast species isolated from tropical habitats

Four yeast isolates with an affinity to the genus Wickerhamiella were obtained from beach sand, a marine zoanthid and a tree exudate at different localities in Brazil. Two other isolates with almost identical ITS and D1/D2 sequences of the large subunit rRNA gene were isolated from the small intestine of cattle and a grease trap in Thailand. These isolates represent a novel species phylogenetically related to Wickerhamiella verensis, Wickerhamiella osmotolerans, Wickerhamiella tropicalis, Wickerhamiella sorbophila and Wickerhamiella infanticola. The novel species differs by 15-30 nucleotide differences from these species in the D1/D2 sequences. The name Wickerhamiella martinezcruziae f.a., sp. nov. is proposed. The holotype of Wickerhamiella martinezcruziae sp. nov. is CBS 16104^T. The MycoBank number is MB 839328.

Multiloci identification of Diaporthe fungi isolated from the medicinal plant Costus spiralis (Jacq.) Roscoe (Costaceae)

AIMS

The purpose of this study is to identify species from genus Diaporthe associated with a medicinal plant Costus spiralis by ITS, EF 1-α, TUB and CAL gens.

METHODS AND RESULTS

The 30 isolates from the genus Diaporthe associated with the medicinal plant Costus spiralis were characterized based on morphological characters and the microculture technique and grouped by DNA fingerprinting with the ISSP gene. Afterwards, a total of 12 isolates were selected for the identification of the species based on the comparative research on the blast through the sequences of the ITS gene. Phylogenetic Tree of Maximum Likelihood were generated with the ITS gene individually and with the genes ITS, TUB, CAL and EF1-α combined with the Diaporthe species recognized and with the additional sequences obtained from GenBank for these species.

CONCLUSIONS

It was not possible to characterize the 30 isolates microscopically and macromorphologically through the microculture technique and the macromorphological characteristics. The 12 isolates selected based on the DNA fingerprinting profile identified phylogenetically, revealed five distinct species of Diaporthe which are present in C. spiralis.

SIGNIFICANCE AND IMPACT OF THE STUDY

The molecular analyses used in this study are excellent alternatives for species-level identification of Diaporthe associated with medicinal plants.

Wickerhamiella slavikovae sp. nov. and Wickerhamiella goesii sp. nov., two yeast species isolated from natural substrates

Two novel yeast species were isolated during three independent studies of yeasts associated with natural substrates in Brazil and Taiwan. Analysis of the sequences of the D1/D2 domains of the large subunit rRNA gene showed that these novel species belong to the Wickerhamiella clade. The first was isolated from freshwater and a leaf of sugar cane (Saccharum officinarum) in Brazil and from leaves of Wedelia biflora in Taiwan. Described here as Wickerhamiella slavikovae sp. nov., it differs by 56 nucleotide substitutions and 19 gaps in the D1/D2 region of the large subunit rRNA gene from Candida sorbophila, the least divergent species. The second species, named Wickerhamiella goesii sp. nov., was isolated from leaves and the rhizosphere of sugar cane collected in Rio de Janeiro, Brazil. The species differs by 54 nucleotide substitutions and nine gaps in the D1/D2 domains from Candida drosophilae, its least divergent relative. The type strains are Wickerhamiella slavikovae sp. nov. IMUFRJ 52096T ( = CBS 12417T = DBVPG 8032T) and Wickerhamiella goesii sp. nov. IMUFRJ 52102T ( = CBS 12419T = DBVPG 8034T).

Bandoniozyma gen. nov., a genus of fermentative and non-fermentative tremellaceous yeast species

BACKGROUND

Independent surveys across the globe led to the proposal of a new basidiomycetous yeast genus within the Bulleromyces clade of the Tremellales, Bandoniozyma gen. nov., with seven new species.

METHODOLOGY/PRINCIPAL FINDINGS

The species were characterized by multiple methods, including the analysis of D1/D2 and ITS nucleotide sequences, and morphological and physiological/biochemical traits. Most species can ferment glucose, which is an unusual trait among basidiomycetous yeasts.

CONCLUSIONS/SIGNIFICANCE

In this study we propose the new yeast genus Bandoniozyma, with seven species Bandoniozyma noutii sp. nov. (type species of genus; CBS 8364(T)  =  DBVPG 4489(T)), Bandoniozyma aquatica sp. nov. (UFMG-DH4.20(T)  =  CBS 12527(T)  =  ATCC MYA-4876(T)), Bandoniozyma complexa sp. nov. (CBS 11570(T)  =  ATCC MYA-4603(T)  =  MA28a(T)), Bandoniozyma fermentans sp. nov. (CBS 12399(T)  =  NU7M71(T)  =  BCRC 23267(T)), Bandoniozyma glucofermentans sp. nov. (CBS 10381(T)  =  NRRL Y-48076(T)  =  ATCC MYA-4760(T)  =  BG 02-7-15-015A-1-1(T)), Bandoniozyma tunnelae sp. nov. (CBS 8024(T)  =  DBVPG 7000(T)), and Bandoniozyma visegradensis sp. nov. (CBS 12505(T)  =  NRRL Y-48783(T)  =  NCAIM Y.01952(T)).

Wickerhamiella pagnoccae sp. nov. and Candida tocantinsensis sp. nov., two ascomycetous yeasts from flower bracts of Heliconia psittacorum (Heliconiaceae)

Two novel yeast species were isolated from nectar of flower bracts of Heliconia psittacorum (Heliconiaceae) collected in a Cerrado ecosystem in the state of Tocantins, northern Brazil. Wickerhamiella pagnoccae sp. nov., which is closely related to Candida jalapaonensis, is heterothallic and produces one spheroid ascospore per ascus. Candida tocantinsensis sp. nov. belongs to the Metschnikowiaceae clade and its nearest relative is Candida ubatubensis, but the sequence identity (%) in the D1/D2 domains of the rRNA gene is low. The type strain of W. pagnoccae is UFMG-F18C1T ( = CBS 12178T = NRRL Y-48735T) and the type strain of C. tocantinsensis is UFMG-F16D1T ( = CBS 12177T = NRRL Y-48734T).

Reduction of aflatoxin B1 in stored peanuts (Arachis hypogaea L.) using Saccharomyces cerevisiae

Aflatoxin B(1) is a toxigenic and carcinogenic compound produced by Aspergillus flavus and Aspergillus parasiticus. To inhibit aflatoxin contamination of peanuts, seeds of two peanut breeds, IAC Caiapó and IAC Runner 886, were inoculated with A. parasiticus (1.0 × 10(6) spores per ml) and the yeast Saccharomyces cerevisiae (3.2 × 10(7) cells per ml) and incubated at 25°C for 7 and 15 days. Two experiments were conducted for each incubation period separately. The treatments were completely randomized, with three replications per treatment. Treatments included the two cultivars and three types of inoculation (pathogen alone, yeast and pathogen, and yeast 3 h before pathogen). Aflatoxin B(1) was quantified with a densitometer at 366 nm after thin layer chromatography. Aflatoxin B(1) contamination in peanuts was reduced after the addition of S. cerevisiae. The concentration of aflatoxin B(1) decreased by 74.4 and 55.9% after 7 and 15 days, respectively. The greatest aflatoxin reduction was observed when S. cerevisiae was inoculated 3 h before the pathogen in IAC Caiapó seeds and incubated for 7 days at 25°C. The use of S. cerevisiae is a promising strategy for biological control of aflatoxin contamination in peanuts.

Yeast communities in two Atlantic rain Forest fragments in Southeast Brazil

We studied the yeast communities associated with fruits, mushrooms, tree exudates, and flies of the genus Drosophila, in two Atlantic Rain Forest fragments in state of Minas Gerais, Brazil. A total of 456 samples were collected from Rio Doce State Park and 142 from Ecological Station of Universidade Federal de Minas Gerais. From these samples, 608 yeast isolates were obtained, belonging to 71 different species. Among the yeasts isolated from Rio Doce State Park, 17 isolates were recovered from fruits, 12 from mushrooms, 13 from tree exudates, and 299 from Drosophila spp. In the Ecological Station of Universidade Federal de Minas Gerais, 24 isolates were recovered from fruits and 243 from Drosophila spp. Distinct communities of yeast were observed in Drosophila flies, fruits, mushrooms and tree exudates. The highest number of yeast species was recovered from Drosophila flies suggesting that flies are the natural vectors of these microorganisms.

Biological control of Penicillium italicum, P. digitatum and P. expansum by the predacious yeast Saccharomycopsis schoenii on oranges

In this study we evaluated the ability of Saccharomycopsis schoenii Nadson and Krassiln (UWO-PS 80-91) as biocontrol agent against plant pathogenic filamentous fungi P. expansum Link (UFMG 01-2002), P. italicum Wehmer (LCP 61.1199), and P. digitatum (Pers.: Fr.) (LCP 984263, LCP 68175 and LCP 4354). S. schoenii was able to reduce disease severity in oranges inoculated with all fungi. Among the phytopathogens, P. digitatum LCP4354 was the most virulent whereas P. digitatum LCP 68175 was the most susceptible to predation. The yeast was able to survive for 21 days on the fruit surface and did not produce lesions on oranges. Production of antagonistic substances by S. schoenii was not detected using standard techniques. Our results point to the potential use of S. schoenii to control postharvest phytopathogens in fruits.

Metschnikowia cerradonensis sp. nov., a yeast species isolated from ephemeral flowers and their nitidulid beetles in Brazil

A novel yeast species, Metschnikowia cerradonensis sp. nov., is described from 12 strains isolated from flowers of Ipomoea carnea and from beetles of the genus Conotelus in the Cerrado ecosystem in the region of Jalapão, Tocantins State, Brazil. Analysis of the sequences of the rRNA gene cluster suggested that M. cerradonensis is closely related to Metschnikowia santaceciliae, Metschnikowia continentalis and an undescribed species represented by strain UWOPS 00-154.1. These species mate together but ascospores are very rarely formed, showing that they represent distinct biological species. M. cerradonensis is apparently endemic to the Cerrado ecosystem of the Jalapão area. The type strain of M. cerradonensis is UFMG 03-T67.1T (h+) (=CBS 10409T=NRRL Y-48067T) and the designated allotype is UFMG 03-T68.1 (h−) (=CBS 10410=NRRL Y-48068).

Geotrichum silvicola sp. nov., a novel asexual arthroconidial yeast species related to the genus Galactomyces

Four strains of an asexual arthroconidial yeast species were isolated from Drosophila flies in two Atlantic rain forest sites in Brazil and two strains from oak tasar silkworm larvae (Antheraea proylei) in India. Analysis of the sequences of the D1/D2 large subunit rRNA gene showed that this yeast represented a novel species of the genus Geotrichum, described as Geotrichum silvicola sp. nov. The novel species was related to the ascogenous genus Galactomyces. The closest relatives of Geotrichum silvicola were Galactomyces sp. strain NRRL Y-6418 and Galactomyces geotrichum. The type culture of Geotrichum silvicola is UFMG-354-2T (=CBS 9194T=NRRL Y-27641T).

Candida sergipensis, a new asexual yeast species isolated from frozen pulps of tropical fruits

Sixteen strains of the new yeast species Candida sergipensis have been isolated from frozen pulps of the tropical fruits umbú ( Spondias tuberosa Avr. Cam.) and mangaba ( Hancornia speciosa Gom.). Candida sergipensis was one of the prevalent species in the yeast community of these substrates. The new asexual ascomycetous yeast is phylogenetically related to Candida spandovensis and Candida sorbophila, species belonging to the Wickerhamiella clade, as evidenced by the sequences of the D1/D2 domains of their large subunit ribosomal DNAs. The species C. sergipensis and C. spandovensis can be separated on the basis of growth on 50% glucose agar, xylose and succinate, negative for the first species and positive for the second. The type culture is strain UFMG-R188 (CBS 9567).