RESUMO
Species of Trichoderma are widely distributed around the world. In this study, two new species in Trichoderma, named as T.albidum and T.variegatum, were introduced and illustrated. These species were isolated from diseased tubers of Gastrodiaelata in China and identified based on morphological characteristics and multi-gene sequence analyses of three loci that is the internal transcribed spacer regions of the ribosomal DNA (ITS), the translation elongation factor 1-α encoding gene (tef1-α) and the gene encoding the second largest nuclear RNA polymerase subunit (rpb2). Distinctions between the new species and their close relatives were discussed. According to results of the phylogenetic analyses, T.albidum belonged to the Harzianum clade and T.variegatum are grouped with species of the Spirale clade. The expansion of two clades provided research foundations for the prevention and control of tuber diseases in G.elata.
RESUMO
BACKGROUND: Aspergillus niger is generally considered safe and is widely used across a broad range of industries from food to pharmaceuticals. The metabolites of some Aspergillus species are effective in killing nematodes. The active ingredients that play a role are citric acid and oxalic acid. RESULTS: The effective nematocidal metabolite in the fermentation broth of the A. niger Ym16 is a calcium oxalate coordination compound (C2 H2 O4 â¢2(C2 HO4 )â¢C2 O4 â¢4(H2 O)â¢2(Ca)). The mortality of fermentation broth and compound solution to second-stage juveniles (J2s) of Meloidogyne incognita were 94% (8 h) and 95% (2 h), respectively. The hatching inhibition rates of fermentation broth and compound solution to eggs of M. incognita were 86% (24 h) and 87% (12 h), respectively. Furthermore, the Ym16 strain promoted plant growth. CONCLUSION: Strain Ym16 and its metabolites should be the first choice for nematode control because it is an effective agent against soil nematodes. © 2023 Society of Chemical Industry.