RESUMEN
Sporodochia are dense masses of fungal hyphae bearing asexual conidia. For Fusarium oxysporum, sporodochia are known to produce airborne conidia and enhance the dissemination of this otherwise soilborne pathogen. Sporodochia are small and transient, and they are documented for only a few formae speciales of F. oxysporum. This study reports airborne conidia and sporodochia produced by F. oxysporum f. sp. fragariae, the cause of Fusarium wilt of strawberry, in the Monterey Bay region of California. Sporodochia were discovered in 21 of 24 Fusarium wilt-diseased fields surveyed for this study and were readily observed on most symptomatic plants in these fields. Only necrotic tissues bore sporodochia, and they were most frequently observed on petioles and peduncles. Sporodochia covered significantly greater lengths of peduncles than petioles, extending from the base of the plant toward the upper part of the canopy. A stolon hosted the longest stretch of sporodochial growth, found covering the stolon's entire 35-cm length and the base of the daughter plant. Macroconidia were produced by all sporodochia samples, and we did not find microconidia on any samples. An initial series of experiments confirmed the potential for conidia produced by sporodochia to disperse with wind over short distances. The prevalence of sporodochia producing airborne spores of F. oxysporum f. sp. fragariae has great importance for disease management and biosecurity. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
RESUMEN
Clonostachys rosea, an ascomycetous, omnipresent, cellulose-decaying soil fungus, has been reported to be a well-known mycoparasitic biological control agent. In this study, we isolated C. rosea, a mycoparasitic fungus for the first time in India from sclerotia of the notorious plant pathogen Sclerotinia sclerotiorum, causing head rot disease in cabbage. A total of five mycoparasitic fungi were isolated from the sclerotial bodies of S. sclerotiorum (TNAU-CR 01, 02, 03, 04 and 05). All the isolates were tested under morpho-molecular characterization. Among them, TNAU-CR 02 showed the greatest mycelial inhibition of 79.63% over the control. Similarly, the SEM imaging of effective C. rosea isolates indicated the presence of numerous conidia destroying the outer cortex layers of sclerotia. Metabolite fingerprinting of C. rosea TNAU-CR 02 identified 18 chemical compounds using GC-MS analysis. The crude antibiotics of C. rosea TNAU-CR 02 were verified for their antifungal activity against S. sclerotiorum and the results revealed 97.17% mycelial inhibition compared with the control. Similarly, foliar application of TNAU-CR 02 at 5 mL/litre on 30, 45 and 60 days after transplanting showed the lowest disease incidence of 15.1 PDI compared to the control. This discovery expands our understanding of the biology and the dissemination of C. rosea, providing a way for the exploitation of C. rosea against cabbage head rot pathogens.
RESUMEN
Cucumber (Cucumis sativus L.) is an important vegetable crop for Mexico, which is the fifth highest producer of this crop worldwide. In November 2019, a fruit rot disease characterized by the presence of white mycelial growth at both ends of the fruit was observed with an incidence of approximately 30% in a greenhouse production area in Sinaloa State (geographical coordinates: 24°35'25'' N, 107°26'21'' O). Culture of small disinfected sections from cucumber lesion edges was carried out on PDA medium at 27°C for seven days. Colonies had profuse aerial mycelium that was initially white and became beige with age, and light orange sporodochia were eventually produced. Macroconidia had 3 to 5 septa and were slightly curved and tapered at the apex with a foot shape at one end and measured 25.4±2.5 × 2.8±0.3 µm. Microconidia were fusoid in form mostly with 2 to 4 septa and measured 15.7±2.04 × 2.4±0.25 µm (n= 100). The morphological characteristics of this fungal isolate were similar to those of Fusarium incarnatum (Leslie and Summerell, 2006). To confirm the species identification, the internal transcribed spacer (ITS) region, calmodulin (CAL), ß-tubulin (B-tub) and translation elongation factor 1-α (TEF1-α) genes were amplified and sequenced from two representative isolates: FPM01 and FPM02. These sequences were submitted to GenBank with accession numbers MT387313 and MT387314 for the ITS region, MT410503 and MT410506 for CAL, MT410502 and MT410505 for B-tub and MT410504 and MT410507 for TEF1-α for the FPM01 and FPM02 isolates, respectively. BLASTn analysis of the sequences showed between 99.33 and 100% identity with F. incarnatum sequence accession numbers MH865893, LN901598, AB587036 and MK328877, which corresponded to strains CBS 130313, ITEM 6748, MAFF 236521 and FIAD-1, respectively. Further BLAST searches in the FUSARIUM-ID database indicated that these sequences had between 99.76 and 100% identity with sequences of the F. incarnatum-equiseti species complex (FIESC) (FD_01682, FD_01640 and FD_01643). To fulfill Koch's postulates, healthy cucumber fruits were disinfected with 1% NaOCl for one min and then washed with distilled water. Ten nonwounded cucumber fruits were spray inoculated with a conidial suspension (1 × 103 conidia/mL), and five fruits wounded with a sterilized needle were inoculated with mycelial discs (6 mm) at three sites each. Distilled water and PDA medium discs were used as controls. All fruits were placed into plastic bags with 80% relative humidity and incubated at 25°C for three days. At 24 hours after inoculation (hai), a soft rot symptom was observed at the fruit poles on non-wounded fruits and around the inoculated area of wounded fruits, and white mycelial growth was observed at 48 hai for both cases. All inoculated fruit showed similar symptoms to those observed initially in the field, and the control fruits remained healthy. The cultures obtained from tissues of inoculated fruits were similar to those from the initially obtained isolates, thus confirming pathogenicity. Recently, Fusarium incarnatum has been reported in China, causing fruit rot in muskmelon (Cao et al., 2019) and peach (Zhang et al., 2020) and crown rot and leaf spot in cucumber (Mao et al., 2020; Gao et al., 2020). To our knowledge, this is the first report of cucumber fruit rot caused by F. incarnatum in Mexico.
RESUMEN
Myrothecium sensu lato includes a group of fungal saprophytes and weak pathogens with a worldwide distribution. Myrothecium s.l. includes 18 genera, such as Myrothecium, Septomyrothecium, Myxospora, all currently included in the family Stachybotryaceae. In this study, we identified 84 myrothecium-like strains isolated from turfgrasses and their rhizosphere. Five new species, i.e., Alfariapoae, Alf.humicola, Dimorphisetaacuta, D.obtusa, and Paramyrotheciumsinense, are described based on their morphological and phylogenetic distinctions. Phylogenies were inferred based on the analyses of sequences from four DNA loci (ITS, cmdA, rpb2 and tub2). The generic concept of Dimorphiseta is broadened to include a third type of seta, i.e. thin-walled, straight with obtuse apices.
RESUMEN
During a survey of fungal species in South Korea, a species of Volutella ciliata was isolated and described based on the analysis of the internal transcribed spacer region of its rDNA and its morphological characteristics. This is the first record of Volutella ciliata isolated from crop field soil in Korea.
RESUMEN
During a survey of fungal species in South Korea, a species of Volutella ciliata was isolated and described based on the analysis of the internal transcribed spacer region of its rDNA and its morphological characteristics. This is the first record of Volutella ciliata isolated from crop field soil in Korea.