Identification,biological characterization and inhibitory effect of fungicides on the pathogen causing Polygonatum cyrtonema
The authors in this study collected Polygonatum cyrtonema leaves with typical symptoms of leaf spot disease,isolated its fungal pathogen,identified the fungal pathogen by adopting morphological characteristics and polygene sequence analysis,probed deep into the biological characteristics of the fungal pathogen,and de-termined the inhibitory effect of fungicides on its colony growth using the mycelial growth rate method.As clearly illustrated by the results,the conidia of the isolated fungal pathogen are colorless,and most of them are pear or long pear-shaped,with the size of(10-12)μm ×(5-7)μm.As evidently proven by the combined analysis of multiple genes,the pathogen has 100％homology with Phyllostacta capitalensis.Combined with morphological characteristics and polygene sequence analysis,the pathogen was identified as Ph.capitalensis,which is the first report of Ph.capitalensis infecting Po.cyrtonema;PDA medium is advantageous for mycelial growth and sporu-lation.To be specific,the mycelium grows fastest and produces the largest number of spores at 25 ℃.When the pH is 5.0-10.0,the mycelium can grow.The optimum pH for spore production is 7.0.The optimum carbon and nitrogen sources for mycelium growth are sucrose and trypsin,respectively,and the optimum carbon source for spore production is glucose.Nonetheless,no spore was produced when yeast,glycine,and beef extract were used as nitrogen sources.Light and dark alternation are suitable for its growth,and light conditions can facilitate the spore production of pathogen.Among the nine tested drugs,triadimefon,EC50=0.292 mg·L-1,has a strong inhibitory effect on Ph.capitalinsis.The results obtained in this study provide a theoretical basis for the control of Po.cyrtonema in production.
Polygonatum cyrtonemaPhyllosticta capitalensisisolation and identificationpolygene sequence analysisbiological characteristicsinhibitory effect
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