Culture storage age and fungal re‐isolation from host‐tissue influence Colletotrichum spp. virulence to pepper fruits

Abstract

Using resistant cultivars is the most sustainable and practical approach against plant diseases. Plant germplasm and breeding lines are selected and assayed against, usually, the most aggressive or virulent strains of a pathogen (e.g., fungus) that causes the disease. However, prolong storage of the pathogen in culture media could affect virulence that, consequently, also influence the outcome of the resistance assay. This study demonstrates that long‐term storage (at least a year) of Colletotrichum truncatum and C. scovillei, causal agents of pepper anthracnose, in potato dextrose agar (PDA) medium decreased the aggressiveness and virulence of the fungus in host‐pepper fruits. However, reintroduction of the pathogen to the host and isolation of the pathogen as the new inoculum, prior to inoculation assays, increased the virulence of the fungi. These findings suggest that re‐inoculation and re‐isolation of Colletotichum truncatum and C. scovillei that have been stored for at least 1 year in PDA medium are necessary when using fungal cultures in pathogenicity and plant resistance assays to achieve desirable, comparable and reliable results.

Identification of Paramyrothecium foliicola causing crater rot in eggplant and its potential hosts under controlled conditions

“…Another problem is that symptoms of crater rot in solanaceous fruits, that is eggplant, tomato and peppers, may be confused with fruit anthracnose (Balendres et al, 2019). Therefore, misidentification of the causative agent of disease could impact the selection of disease control measures.…”

A rapid and efficientin vivoinoculation method for introducing tree stem canker pathogens onto leaves: Suitable for large-scale assessment of resistance in poplar breeding progeny

“…However, some fungal isolates cannot grow over a 9 cm diameter Petri dish in 7 days; for example, some V. sordida isolates, to harvest more mycelium inoculants, the culture conditions of canker pathogens suggested as follows: cultured on PDA medium, at 28℃, in dark condition, for seven days. Some researchers considered that the most aggressive or virulent strains of a pathogen that causes the disease should be used in the selection and assays of plant germplasm and breeding lines (Balendres et al, 2019). This selection strategy may be beneficial to the funding of the authentic highest resistance clones in the breeding population; however, it also may be a disaster for the whole breeding program for the disease or even the death of all offspring, or it has no breeding significance for the other poor production phenotypes.…”

“…Some researchers considered that the most aggressive or virulent strains of a pathogen that causes the disease should be used in the selection and assays of plant germplasm and breeding lines (Balendres et al ., 2019). This selection strategy may be beneficial to the funding of the authentic highest resistance clones in the breeding population; however, it also may be a disaster for the whole breeding program for the disease or even the death of all offspring, or it has no breeding significance for the other poor production phenotypes.…”

Comparative Study on the Effectiveness of Three Inoculation Methods for Valsa sordida in Populus alba var. pyramidalis

“…pyramidalis. In this context, the remarkable inoculation outcomes may be attributed to the high vitality of the pathogen colonized onto the toothpicks [21]. Additionally, the depth of the wound caused by toothpick inoculation creates a relatively deeper saprotrophic environment than the other two inoculation methods, facilitating the invasion of V. sordida [5].…”