Mycelia growth and sporulation of Fusarium chlamydosporum species complex under different culture conditions

Abstract

The Fusarium genus exhibits morphological, physiological and genetic variation among its different species, which may lead to differences in the environmental conditions required for their cultivation. This study aimed to verify the effects of different culture media and lighting regimes on the mycelial growth and sporulation of Fusarium chlamydosporum species complex isolates that are pathogenic to Carya illinoinensis. Four isolates from infected Carya illinoinensis roots and inflorescences were selected; these isolates were purified and subsequently transferred to four different culture media: potato sucrose agar (PSA), water agar (WA), potato dextrose agar (PDA) and carnation leaf agar (CLA). The isolates were then submitted to three different lighting regimes: a photoperiod of 12 h (TL), continuous light (CL) and continuous darkness (CD). After seven days of incubation under the three lighting regimes, the mycelial growth was evaluated on PSA, WA and PDA, and sporulation was evaluated on PSA, WA, PDA and CLA. In general, PSA and BDA media support mycelial growth and sporulation, particularly under CL. CLA medium also supports sporulation, particularly under CL. The CD lighting regime and the WA medium are not recommended for either the mycelial growth or sporulation of the F. chlamydosporum species complex. RESUMO: O gênero Fusarium apresenta diversas variações morfológicas, fisiológicas e genéticas entre suas espécies, portanto diferentes condições ambientais de cultivo podem ser requeridas. O objetivo deste estudo foi verificar os efeitos do uso de diferentes meios de cultura e regimes de luminosidade no crescimento micelial e na esporulação de isolados de Fusarium chlamydosporum species complex patogênicos a Carya illinoinensis. Foram selecionados quatro isolados patogênicos coletados de inflorescências e raízes infectadas de C. illinoinensis, os quais foram purificados e repicados para quatro meios de cultura: Batata-sacarose-ágar (BSA), Ágar-água (AA), Batata-dextrose-ágar (BDA) e Folha-decravo-ágar (CLA), e submetidos a três regimes de luminosidade: fotoperíodo de 12 h (FT), luz contínua (LC) e escuro contínuo (EC). Após sete dias de incubação, foi avaliado o crescimento micelial em BSA, AA e BDA, e a esporulação nos meios BSA, AA, BDA e CLA, nos três regimes de luminosidade. Os meios BSA e BDA favoreceram o crescimento em diâmetro e a esporulação, especialmente sob LC. O meio CLA também promoveu a esporulação, principalmente sob LC. O regime de luminosidade EC e o meio de cultura AA não são recomendados para crescimento e, especialmente, para esporulação de F. chlamydosporum species complex. Mycelia growth and sporulation of Fusarium chlamydosporum species complex under different culture conditions Crescimento micelial e esporulação de Fusarium chlamydosporum species complex sob diferentes condições de cultivo

Effect of culture medium light and air circulation on sporulation of <i>Neonectria ditissima</i>

“…Similar to the findings of Etebu et al (2005), Lazarotto et al (2014) and W. Molhoek (Wageningen UR, Plant Research International, personal communication), this study showed that light is required for abundant production of viable multi-celled conidia. Fewer isolates produced conidia in the dark compared with isolates exposed to NUV light, and isolates that were kept in the dark produced only 1and 2-celled conidia.…”

“…These results differ from Etebu et al (2005) who reported that sporulation of Mycosphaerella fijiensis was significantly higher under NUV light than white light. However, Lazarotto et al (2014) reported that Fusarium chlamydosporum sporulated well in culture under white light, and Dubin & English (1974) reported that a single ascospore isolate of N. ditissima produced abundant, pathogenic, multi-septate conidia under Sylvania Gro-Lux fluorescent lights, confirming that normal fluorescent light is suitable for conidium production of N. ditissima.…”

Fusarium oxysporum and F. verticillioides associated with damping-off in Pinus spp.

“…Silva and Teixeira (2012) found an average sporulation of 3.09 x 10 3 conidia mL -1 for F. solani, using 12-hour photoperiod and PDA medium. On the other hand, Lazarotto et al (2014), in tests with to the culture complex Gibberella fujikuroi on LCA culture medium, found high levels of sporulation, reaching 12.68 × 10 6 conidia mL -1 for one of their isolates (F5). The LCA medium favors the ultimate expression of the characteristics and sporulation of the genus Fusarium (NELSON; TOUSSON;MARASAS, 1983;VENTURA, 1999).…”

Evaluation of fresh culture media for mycelial growth and conidial production of Botrytis fabae, causing chocolate spot on faba bean (Vicia faba L.)

“…The spore suspension obtained was filtered through two layers of sterile gauze and was poured into a small beaker, the plate was rinsed thoroughly, and the final volume was adjusted to 20 ml by adding sterile distilled water (Lazarotto et al, 2013). For CFDA medium, being conidia dislodging with washing was not successful, the medium was suspended in 20 ml sterilized distilled water and gently milled with the help of laboratory blender to ensure complete detachment of spores.…”

“…It is well known that growth and sporulation are important phases during the life of fungi, which is considerably influenced by external growth factors (Mishra and Tripathi, 2015). Among the external growth factors, nutrition was one of the determinants that were previously proved by several workers in many fungal pathogens using different culture media sources (Kasar et al, 2004;Rani and Murthy, 2004;Younis et al, 2004;Kim et al, 2005;Zhao et al, 2010;Lazarotto et al, 2013).…”