Infection process of Curvularia gladioli on gladiolus leaves

Abstract

Curvularia leaf spot, caused by Curvularia gladioli, is an important disease of gladiolus. Inoculated leaf samples of the Gladiolus grandiflorus 'T-704' and 'Veronica' varieties were obtained 1 to 192 h after inoculation (hai). There was no difference in the percentage of conidial germination and appressorium formation on the leaves of both varieties. Conidia exhibited polar germination, and most conidia produced one to two germ tubes. Protoappressoria were observed at 1 and 3 hai in 'Veronica' and 'T-704', respectively. The most common form of fungal penetration was direct. Both intracellular and intercellular colonization of the fungal hyphae were observed in 'T-704' (96 hai) and 'Veronica' (192 hai). However, there was less hyphal development in 'Veronica'. Fungal sporulation occurred in both varieties 7 to 8 days after inoculation. Conidiophores were observed emerging through the papillae and stomatal openings in both gladiolus varieties, but were visually more abundant for 'T-704'. This study provides insights into the infection process of C. gladioli on gladiolus leaves.

Infection process of Pseudobeltrania cedrelae associated with Phyllachora balansae on Cedrela fissilis leaves

“…Sporulation occurred on the abaxial surface in conidiophores that emerged through the epidermis and stomata, which was also observed for C. gladioli on gladiolus leaves (Torres et al, 2015). The conidiophore emission only through the rupture of the leaf epidermis was observed for B. cinerea on eucalyptus (Caires et al, 2015).…”

“…This suggests that P. cedrelae, although influenced by P. balansae during the prepenetration phase on C. fissilis leaflets, is able to colonize and reproduce in this host tissue. Inter-and intracellular colonization of leaves was also observed for C. coffeicola in coffee, B. cinerea in eucalyptus, C. gladioli in gladiolus and Pestalotiopsis longisetula in strawberry (Caires et al, 2015, Rodrigues et al, 2014, Souza et al, 2011, Torres et al, 2015.…”

“…This characteristic was also observed in the interactions Botrytis cinerea-eucalyptus (Caires et al, 2015), Curvularia gladioli-gladiolus (Torres et al, 2015) and Cercospora coffeicola-coffee (Souza et al, 2011). The development of more than one germ tube can be considered a way to increase aggressiveness, since it increases the chance of having more penetration sites (Babu et al, 2009).…”

“…Colletotrichum gloeosporioides on coffee (Ferreira et al, 2009) and C. gladioli on gladiolus (Torres et al, 2015).…”

“…The epidermis of the fragments collected at 144 and 408 hai was removed with the aid of an adhesive tape. Then, the samples were plated with gold in the sputter coater apparatus coupled to the freezing drying unit (Bal-tec, model FDU010), and observed and photographed in a scanning electron microscope (SEM; LEO, model 1430VP) operating at 20 Kv (Torres et al, 2015).…”