First Report of Curvularia richardiae Causing Leaf Blight on Richardia brasiliensis in Brazil.

Richardia brasiliensis (Rubiaceae), also known as white eye or 'poaia-branca' in Brazil, is an important agricultural weed in the tropics (2). Relatively little is known about diseases affecting this species. In March 2013, all of the plants of this weed species invading an orchid plantation in Nova Friburgo (State of Rio de Janeiro) and a private orchard at Viçosa (State of Minas Gerais) in Brazil were found to bear intense leaf blight symptoms. Lesions were circular to elliptical, 1.4 to 10.5 mm in diameter, grayish to pale brown, and coalesced leading to necrosis of large areas of the leaves. Leaf samples were collected, dried in a plant press, and representative specimens deposited in the local herbarium at the Universidade Federal de Viçosa (Accession Nos. VIC 39759 and VIC 39760). A fungus found in association with diseased tissues was isolated by directly transferring conidia from infected leaves onto PDA plates, and two isolates were deposited in a local culture collection (COAD Accession Nos. 1335 and 1443). Conidia were removed from infected leaves using a scalpel, and mounted in lactophenol and lactofuchsin for observation with a light microscope (Olympus BX 51). Conidiophores were epiphylous, isolated, subcylindrical, straight to slightly curved, 97.5 to 170.0 × 5.0 to 8.0 µm, 2 to 6 septate, unbranched, pale brown and paler towards the apex, and smooth. Conidia were straight to slightly curved, pyriform to obovoid, 35.5 to 43.5 × 12.5 to 25.0 µm, with the apex rounded and the base subacute, 1 to 3 distoseptate, the subterminal cell often dark brown and larger than the other cells (sometimes leading to the distortion and curving of conidia); the other cells were golden brown and the conidia were smooth. The morphology of the fungus on R. brasiliensis was equivalent to that described for Curvularia richardiae (1). Genomic DNA was extracted from a 7-day-old pure culture of both isolates, and the large subunit (LSU) region of ribosomal DNA (rDNA) was amplified with the primers LR0R/LR5 (3). The resulting sequences were deposited in GenBank (KF880800 and KF880801). A BLASTn search revealed 99% similarity of the two isolates from Brazil with the LSU sequence of an isolate of Cochiobolus geniculatus (JN941528). Three healthy, 10-cm-tall R. brasiliensis plants were inoculated with a conidial suspension (1 × 106 conidia/ml) of isolate COAD 1335 until runoff, and the plants kept for 2 days in a dew chamber at 26 ± 3°C. Additionally, two plants were sprayed with distilled water and kept under the same conditions. Six days after inoculation, symptoms appeared on all inoculated plants that were similar to symptoms on plants in the field. Non-treated control plants remained healthy. C. richardiae was isolated from the lesions on inoculated plants. Although there is an incomplete record of a Curvularia sp. associated with seeds of R. brasiliensis in Brazil (4), that record included no description of the fungus or information on a disease caused on the plants. This is the first report of C. richardiae causing a disease on R. brasiliensis in Brazil. Although the fungus was first described in Australia (1), C. richardiae is most likely a native from the neotropics, as is the host plant, R. brasiliensis. The fungus was probably introduced accidentally into Australia on the weedy host but has remained unnoticed in the native range until now. References: (1) J. L. Alcorn. Trans. Brit. Mycol. Soc. 56:155, 1971. (2) R. R. Rosseto et al. Planta Daninha 15:25, 1997. (3) R. Vilgalys et al. J. Bacteriol. 172:4239, 1990. (4) C. Yamashita et al. Fitopatol. Bras. 13:122, 1988.

First Report of Downy Mildew Caused by Plasmopara halstedii on Gerbera jamesonii in Brazil.

African daisy (Gerbera jamesonii Bolus ex Hook. f.) is an important species for both the cut flower and potted plant industries worldwide (4). Since the winter of 2009, plants showing severe downy mildew symptoms have been observed in a greenhouse located in an experimental area of the Universidade Federal de Viçosa (state of Minas Gerais, Brazil). The disease appeared as ill-delimited adaxial chlorosis of lamina; tissues became yellow and then brown with age with intense blighting of leaves of entire plants, leading to their death, when untreated. Dense, whitish sporulation was observed on the lower surfaces since early stages. A representative sample was dried in a plant press and deposited in the local herbarium under accession number VIC 32070. Slides were prepared with fungal structures mounted in lactofuchsin and observed under a light microscope (Olympus BX 51). Fungus morphology: Sporangiophores hypophyllous, emerging through stomata, cylindrical, up to 650 µm long and 5 to 10 µm wide, with slightly swollen base from 6.5 to 13 µm, hyaline, aseptate, straight, with up to 6 monopodial ramifications occurring mainly at right angles, the final branch ending in 3 or 4 ultimate branchlets; sporangia globose to ovoid, from 20 to 28 µm long and 13 to 18 µm wide, hyaline, smooth. Oospores were not observed. In order to further clarify the identity of the fungus on G. jamesonii, genomic DNA was extracted directly from the plant tissue and part of cytochrome c oxidase subunit 2 was amplified with the primers COX2 (3). The generated sequence was submitted to GenBank (Accession No. KC690148) and when compared with other entries revealed a high sequence similarity (99%) with Plasmopara halstedii (Farl.) Berl. & De Toni (EU743813) from Helianthus annuus L. This was also supported by the morphological data as compared with published descriptions (2) and it was then concluded that the chromistan fungus involved in downy mildew of African daisy was P. halstedii. Two different downy mildew genera, Bremia and Plasmopara, cause downy mildew disease on G. jamesoni. Bremia lactucae has been recorded in Argentina, Brazil, Germany, and Poland (4). There is only one record of a Plasmopara on this host in the United States (1), but this is an obscure report with no identification at the species level. Although P. halstedii has been commonly recorded on numerous hosts belonging to the Asteraceae worldwide, it has never been reported on G. jamesoni. To our knowledge, this is the first report of P. halstedii on G. jamesoni in Brazil. This disease has the potential to become important and cause significant losses because of a combination of the high severity to untreated plants and the increasing importance of African daisy in the flower market in Brazil. References: (1) S. A. Alfieri, Jr. et al. Bull. 11. Index of Plant Diseases in Florida (Revised). Florida Dep. Agric. Consumer Serv., Div. Plant Ind., 1984. (2) G. Hall. Plasmopara halstedii. CMI Descriptions of Pathogenic Fungi and Bacteria No 979. Mycopathologia 106:205, 1989. (3) D. S. S. Hudspeth et al. Mycologia 92:674, 2000. (4) S. M. Wolcan, Australas. Plant Dis. Notes 5:98, 2010.

Reappraisal of the genus Alternariaster (Dothideomycetes).

Alternariaster was erected in 2007 to accommodate Alternaria helianthi, a fungal species known to cause leaf spots on Helianthus annuus (sunflower). It was segregated from Alternaria based on conidial morphology. Recently an unknown alternaria-like dematiaceous fungus was found associated with leaf spots on Bidens sulphurea (yellow cosmos) in Brazil. Based on a multi-gene phylogeny of parts of the ITS and LSU genes, this fungus was placed within the Leptosphaeriaceae with Alternariaster helianthi as its closest neighbour. Additional genes sequenced, RPB2 and GAPDH, confirmed this close relationship. The fungus on B. sulphurea has smaller conidia, 50-97.5 × 12.5-20 µm, compared to Al. helianthi, 80-160 × 18-30 µm, and lacks oblique or transverse septa which can be present in Al. helianthi. Pathogenicity studies on 18 plant species belonging to the Compositae showed that the B. sulphurea fungus only infected B. sulphurea, whereas Al. helianthi infected H. annuus and Galinsoga quadriradiata, a yet unreported host of Al. helianthi. The fungus causing disease on B. sulphurea is hence closely related but phylogenetically, morphologically and pathologically distinct from Al. helianthi, and therefore newly described as Alternariaster bidentis. The collection of a second species in the genus Alternariaster and the multigene phylogenetic analysis of these two species, confirmed Alternariaster to be a well-delimited genus in the Leptosphaeriaceae rather than the Pleosporaceae, to which Alternaria belongs.

Chronotype ontogeny related to gender.

Chronotype is an established concept designed to identify distinct phase relationships between the expression of circadian rhythms and external synchronizers in humans. Although it has been widely accepted that chronotype is subjected to ontogenetic modulation, there is no consensus on the interaction between age and gender. This study aimed to determine the relationship between age- and gender-related changes in the morningness-eveningness character in a large sample of people. A total of 14,650 volunteers were asked to complete the Brazilian version of the Horne and Östberg chronotype questionnaire. The data demonstrated that, on average, women were more morning-oriented than men until the age of 30 and there were no significant differences between men and women from 30 to 45 years of age. In contrast to the situation observed until the age of 30, women older than 45 years were more evening-oriented than men. These results suggest that the ontogenetic development of the circadian timekeeping system is more plastic in men, as represented by the larger amplitude of chronotype changes throughout their aging process. The phase delay of adolescence and phase advance of the elderly seem to be phenomena that are more markedly present in men than in women. Thus, our data, for the first time, provide support that sharply opposes the view that there is a single path toward morningness as a function of age, regardless of gender.

Chronotype ontogeny related to gender

Chronotype is an established concept designed to identify distinct phase relationships between the expression of circadian rhythms and external synchronizers in humans. Although it has been widely accepted that chronotype is subjected to ontogenetic modulation, there is no consensus on the interaction between age and gender. This study aimed to determine the relationship between age- and gender-related changes in the morningness-eveningness character in a large sample of people. A total of 14,650 volunteers were asked to complete the Brazilian version of the Horne and Östberg chronotype questionnaire. The data demonstrated that, on average, women were more morning-oriented than men until the age of 30 and there were no significant differences between men and women from 30 to 45 years of age. In contrast to the situation observed until the age of 30, women older than 45 years were more evening-oriented than men. These results suggest that the ontogenetic development of the circadian timekeeping system is more plastic in men, as represented by the larger amplitude of chronotype changes throughout their aging process. The phase delay of adolescence and phase advance of the elderly seem to be phenomena that are more markedly present in men than in women. Thus, our data, for the first time, provide support that sharply opposes the view that there is a single path toward morningness as a function of age, regardless of gender.