Authors:
Nachaat Sakr
Volume 30, Issue 1;
Pages: 40-49; 2024
ISSN: 2069-0053 (print), Agroprint;
ISSN (online): 2068-9551
Fusarium head blight (FHB), spot blotch (SB) and common root rot (CRR) are the economically ones of the most important fungal disease of wheat, barley, and many other plants of Poaceae family. Efficient and suitable methods for storage of the pathogens can help in achieving the target of sustainable management of these diseases in a relatively short period of time. In this study, we aimed to test suitable methods for storage of Fusarium spp. and Cochliobolus sativus isolates differing in their phenotypical characters collected from the FHB, SB and CRR-infected wheat and barley fields. Our preservation procedure included prolongation of storage duration of two existing protocols, sterile distilled water and freezing, that were available for 16 FHB isolates of four species, 32 SB isolates and 22 CRR isolates. Two storage treatments started in May 2015 and included fungal suspension (spores and hyphae) in sterile distilled water at 4°C and fungal cultures on Petri-dishes after reaching suitable growth by freezing at -16°C were tested in periods ranging up to 9 years. The survival, morphological changes and contamination by other microorganisms were then assessed: phenotypic features were analyzed qualitatively at 6, 12, 18, 24, 30, 36, 60, 96, and 108 months. All these experimental procedures were conducted under aseptic conditions. Fungal isolates were recovered from the two storage treatments having a full viability and maintaining their morphological stability and purity at each time point. Neither employed preservation technique, storage period nor taxonomic identification was linked with a decrease of survival, microbial contamination or morphology changes. Our observations propose that Castellani’s technique and freezing are easy and inexpensive methods for long-term preservation of F. culmorum, F. verticillioides, F. solani, F. equiseti and Cochliobolus sativus, and can be principally used in the creation of stock collections of restricted resources. The present research is the first work showing the possibility of storage for FHB, SB and CRR causal agents utilizing fungal suspension at 4°C in cold water and mycelial cultures by freezing for 9 years.