Morphological Characterization of Corynespora cassiicola Isolates in Culture Media

Abstract

Corynespora cassiicola threatens soybean and cotton production in Brazil. The objective of this study was to evaluate cultural and morphological aspects of C. cassiicola isolated from soybean and cotton of different Brazilian regions, in culture media. The isolates were grown in PDA (Potato Dextrose Agar) and V8 juice agar media. The characteristics evaluated were: color, aspect, and growth rate of mycelia, as well as production and dimension of conidia, and number of septa per conidium. Culture media and isolates were compared using the Kruskal-Wallis or Tukey’s test at 5% significance level. The mycelia of the isolates were predominantly dark gray and light brown. C. cassiicola isolates grew better in V8 juice agar medium, presenting a higher mycelial growth rate. In PDA medium, the production of conidia was higher in isolates from cotton, compared with soybean isolates. There was great variation in the production of conidia in V8 juice agar medium, regardless of the host origin. Conidia length and width varied for isolate and culture medium. The isolates of C. cassiicola coming from cotton presented a higher number of septa per conidium when grown in PDA medium. The morphological aspects of C. cassiicola vary depending on the host of origin and the culture medium.

Morphological and pathogenic characterization of Corynespora cassiicola isolates reveals specific genotypic interactions in soybean

“…Colonies of grey, green, and brown colour were observed, with the majority showing green on both surfaces. In general, the mycelial colour of C. cassiicola from soybean in PDA is predominantly grey (Ferreira Filho, 2012;Puia et al, 2021;Rondon, 2020) or greenish-grey (Ferreira Filho, 2012) at the front of the plates, and grey (Rondon, 2020) or brown (Puia et al, 2021) at the back of the plates. Furthermore, the mycelial aspect of the isolates grown in PDA was aerial cottony, which agrees with that described by Puia et al (2021) for this pathogen isolated from soybean.…”

“…In general, the mycelial colour of C. cassiicola from soybean in PDA is predominantly grey (Ferreira Filho, 2012;Puia et al, 2021;Rondon, 2020) or greenish-grey (Ferreira Filho, 2012) at the front of the plates, and grey (Rondon, 2020) or brown (Puia et al, 2021) at the back of the plates. Furthermore, the mycelial aspect of the isolates grown in PDA was aerial cottony, which agrees with that described by Puia et al (2021) for this pathogen isolated from soybean. Interestingly, when observing the shape of the colonies we found an irregular growth for a minority of the analysed isolates, which has not previously been described for this pathogen.…”