Species separation in Curvularia “geniculata” group inferred from Brn1 gene sequences

Abstract

Brn1, a reductase gene involved in the melanin biosynthetic pathway, was adopted for species delimitation among members in the "geniculata" group of Curvularia species and proved to be useful for this purpose. Phylogenetic trees of these fungal members were constructed from nucleotide sequences of this region. The so-called geniculata group of Curvularia was separated into several clusters. The conidial morphology of the members in each cluster is closely similar but clearly different among discrete clusters. The phylogenetic groups almost concurred with the morphological grouping. Thus, the synonymous treatment of Curvularia affinis, C. fallax, and C. senegalensis to C. geniculata in a previous study was supported. The isolates with warping hilum conidia were clearly different from C. geniculata and separated into two clusters. C. geniculata ATCC 6671 made an independent cluster situated near these clusters. The protuberant hilum species were located separately in the phylogenetic trees. For sound taxonomic treatment of these isolates, we should accumulate more information and retain our species determination for them.

Curvularides A–E: Antifungal Hybrid Peptide–Polyketides from the Endophytic Fungus Curvularia geniculata

“…The resultant phylogenetic tree showed the CTOM11 fungus to be closely affiliated with the C. geniculata cluster. [27] This fungus is thus tentatively identified as Curvularia geniculata CTOM11.…”

“…Alternatively, the DNA sequence of the Brn1 gene encoding 1,3,8-trihydroxynaphthalene reductase, an enzyme in the melanin biosynthetic pathway, was investigated. [27] PCR primers 5'-GCCAACATCGAGCAAA-CATGG-3' and 5'GCAAGCAGCACCGTCAATACCAAT-3' were used to amplify the Brn1 gene from the CTOM11 genomic DNA, and the product was subjected to DNA sequencing on both strands. The DNA sequence obtained was BLAST searched against the GenBank database and was found to be similar to those of some 4-distoseptate conidia Curvularia.…”

IDENTIFICAÇÃO MORFOLÓGICA E MOLECULAR DE Curvularia sp. AGENTE CAUSAL DA MANCHA FOLIAR DO MILHO

“…Contudo, segundo Sun et al (2003), apenas a aná-lise morfológica não fornece informações suficientes para identificação segura de espécies do gênero Curvularia, pois para uma identificação mais precisa é necessário proceder a análise baseada em dados moleculares.…”

“…Vaz-de-Melo et al (2010) relataram o aumento da ocorrência da mancha-de-curvularia na região sul do Estado Tocantins nos últimos anos, encontrando efeito negativo na produtividade.…”

“…Uma delas é que, nos fungos, esta região é amplificada, utilizando-se primers universais, os quais são complementares às sequências altamente conservadas que codificam os genes 18S e 28S de rRNA, sendo os primers ITS1 e ITS4 os mais comumente utilizados na amplificação por PCR e estudos de identificação de isolados e espécies (White et al, 1990 Para caracterização morfológica, foi elaborada uma tabela na qual foram registrados: aspecto do micélio (cotonoso ou ralo), forma dos bordos (regulares ou não), coloração da colônia (preto, verde musgo ou cinza), reverso da colônia (com ou sem pigmentação escura), presença ou ausência de micélio sob o meio…”