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<p>The genus <i>Paraphoma</i> (<i>Phaeosphaeriaceae</i>) consists of a small number of saprotrophic and phytopathogenic species that cause various diseases (root and crown rot, leaf spots) in cultivated and wild plants. Some <i>Paraphoma</i> spp. have been known to produce biologically active secondary metabolites. In this study, <i>Paraphoma</i> fungi isolated from diseased leaves of <i>Cirsium arvense</i> and <i>C.&#xa0;pendulum</i> were characterized using a polyphasic approach combining the study of morphological features, secondary metabolite profiling, and multilocus phylogenetics using the ITS region along with partial <i>TEF1-α</i> and <i>TUB2</i> gene sequences<i>.</i> As a result, two new species (<i>Paraphoma rubrobrunnea</i> sp. nov. and <i>Paraphoma cirsii</i> sp. nov.) were described and then characterized. The pathogenicity of <i>P. rubrobrunnea</i> toward its host <i>C. arvense</i> was proved, while <i>P. cirsii</i> exhibited endophytic growth in leaves of aboveground shoots of this plant. Paraphaeosphaeride D and two carbocyclic aspochalasins (16-hydroxymethylaspergillin PZ and 19-hydroxyl-19,20-dihydrophomacin C) were isolated from liquid cultures of <i>P. rubrobrunnea</i> as its major metabolites. A main metabolite of <i>P. cirsii</i> was phaeosphaeride A. Furthermore, detectable amounts (&lt; 1&#xa0;µg/1 × 10<sup>6</sup> conidia) of paraphaeosphaeride D and phaeosphaeride A were found in the conidial matrix of <i>P. rubrobrunnea</i> and <i>P. cirsii</i> in the pycnidia taken from both the fungal solid cultures and artificially infected leaf discs of <i>C. arvense.</i> The high phytotoxic activity (minimal phytotoxicity concentration of 100&#xa0;µg/mL) of both paraphaeosphaeride D and phaeosphaeride A was confirmed, whereas the moderate leaf phytotoxicity of aspochalasins was revealed for the first time. All isolated compounds exhibited weak antimicrobial activity and showed no insect toxicity. The removing of paraphaeosphaeride D and phaeosphaeride A from conidial suspension of <i>P. rubrobrunnea</i> and <i>P. cirsii</i>, respectively, did not decrease their pathogenicity.</p> Graphical abstract <p></p>

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Paraphoma rubrobrunnea sp. nov. and Paraphoma cirsii sp. nov. from Cirsium species and biological characterization of their phytotoxins

  • 期刊论文

  • 发表日期：

    2025年9月30日

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  • Elizaveta Lukina,
  • Igor Kazartsev,
  • Vsevolod Dubovik,
  • Maria Gomzhina,
  • Sergey Smirnov,
  • Ke Zhang,
  • Qunfang Weng,
  • Alexander Berestetskiy

摘要

The genus Paraphoma (Phaeosphaeriaceae) consists of a small number of saprotrophic and phytopathogenic species that cause various diseases (root and crown rot, leaf spots) in cultivated and wild plants. Some Paraphoma spp. have been known to produce biologically active secondary metabolites. In this study, Paraphoma fungi isolated from diseased leaves of Cirsium arvense and C. pendulum were characterized using a polyphasic approach combining the study of morphological features, secondary metabolite profiling, and multilocus phylogenetics using the ITS region along with partial TEF1-α and TUB2 gene sequences. As a result, two new species (Paraphoma rubrobrunnea sp. nov. and Paraphoma cirsii sp. nov.) were described and then characterized. The pathogenicity of P. rubrobrunnea toward its host C. arvense was proved, while P. cirsii exhibited endophytic growth in leaves of aboveground shoots of this plant. Paraphaeosphaeride D and two carbocyclic aspochalasins (16-hydroxymethylaspergillin PZ and 19-hydroxyl-19,20-dihydrophomacin C) were isolated from liquid cultures of P. rubrobrunnea as its major metabolites. A main metabolite of P. cirsii was phaeosphaeride A. Furthermore, detectable amounts (< 1 µg/1 × 106 conidia) of paraphaeosphaeride D and phaeosphaeride A were found in the conidial matrix of P. rubrobrunnea and P. cirsii in the pycnidia taken from both the fungal solid cultures and artificially infected leaf discs of C. arvense. The high phytotoxic activity (minimal phytotoxicity concentration of 100 µg/mL) of both paraphaeosphaeride D and phaeosphaeride A was confirmed, whereas the moderate leaf phytotoxicity of aspochalasins was revealed for the first time. All isolated compounds exhibited weak antimicrobial activity and showed no insect toxicity. The removing of paraphaeosphaeride D and phaeosphaeride A from conidial suspension of P. rubrobrunnea and P. cirsii, respectively, did not decrease their pathogenicity.

Graphical abstract