Environmental Scanning Electron Microscopy of the Infection Process of Fusarium solani f. sp. passiflorae in Seedlings of Passionfruit (Passiflora edulis f. flavicarpa)

Abstract

Environmental scanning electron microscopy (ESEM) was performed in seedlings of Passiflora edulis f. flavicarpa inoculated with Fusarium solani f. sp. passiflorae (teleomorph: Haematonectria haematococca) causal agent of passionfruit collar rot. Inoculations were carried out every 24 h until the seventh day and from this day until the fifteenth the interval of inoculation was 72 h. The pathogen isolated in PDA media was placed on the surface of the collar through the modified test-tube screening methodology. Epidermis of collar, stem, and leaves and longitudinal sections of collar and stem were observed. After 24 h of inoculation, conidia and dense septate mycelium were observed over the epidermis of the stem and the collar, respectively. Hypertrophy and cell wall degradation of the vascular tissues were also found during this period. Five days after the inoculation macroconidia were formed from monophialides in the aerial mycelium on the stem. Ten days after inoculation, xylem and pith cells of the collar were colonized by hyphae, inclusions, and mature sporodoquia over the stem surface. Hyphae colonization started six days after inoculation on stomata and thirteen days after inoculation monophialides with in situ microconidia were observed over the surface of the leaves. Based on the evidence and previous studies, internal hyphae colonization of F. solani f. sp. passiflorae concentrates on the collar area and the damages of the cells indicate an extracellular enzymatic activity of the fungus. The incubation and latent periods of F. solani f. sp. passiflorae were 1.4 and 4 days, respectively. © 2017. Acad. Colomb. Cienc. Ex. Fis. Nat.Key Words: Plant diseases; fungal diseases; Passifloraceae; collar rot; scanning microscopy. Microscopía electrónica de barrido ambiental del proceso de infección de ResumenSe realizó microscopía electrónica de barrido ambiental (ESEM) en plántulas de maracuyá (Passiflora edulis f. flavicarpa) inoculadas con Fusarium solani f. sp. passiflorae (teleomorfo: Haematonectria haematococca) agente causal de la secadera. Las inoculaciones se realizaron cada 24 h hasta el séptimo día y hasta el día quince el intervalo fue de 72 h. El aislamiento en medio de papa (PDA) se colocó sobre el cuello de la raíz mediante la metodología de cribado en tubos de ensayo modificada. La superficie del cuello, tallo, hojas y secciones longitudinales del cuello y tallo fueron observadas. Después de 24 h de la inoculación, se observaron conidios y micelio denso septado sobre la epidermis del tallo y el cuello e hipertrofia y degradación de la pared celular de los tejidos vasculares. Al quinto día se formaron macroconidios a partir de monofiálides en el micelio aéreo en el tallo. Diez días después, las células del xilema y médula del cuello fueron colonizadas por hifas, esporodoquios maduros e inclusiones. La colonización de las estomas por las hifas comenzó seis días después de la inoculación y trece días después de la inoculación se observaron monofiálides con microconidios in situ sobre la superfi...

Study on the Biocontrol Potential of Antifungal Peptides Produced by Bacillus velezensis against Fusarium solani That Infects the Passion Fruit Passiflora edulis

“…F. solani frequently causes immense economic losses when the control measures are inadequate or improper. 6,7 In addition to strengthening field management, current prevention and the control of basal stem rot mainly rely on chemical control, especially in seasons during which there is a high incidence of infections. Although the application of chemical fungicides reduces agricultural production losses, it also brings heavy environmental risks.…”

“…F. solani frequently causes immense economic losses when the control measures are inadequate or improper. , In addition to strengthening field management, current prevention and the control of basal stem rot mainly rely on chemical control, especially in seasons during which there is a high incidence of infections. Although the application of chemical fungicides reduces agricultural production losses, it also brings heavy environmental risks. , Owing to a reduced burden on the environment, biological control has received constant attention and development at present, and there is an increasing trend of employing biological fungicides and bioactive molecules in combination with or to replace chemical fungicides for disease control.…”

In Vitro Study of the Compatibility of Four Species of Trichoderma with Three Fungicides and Their Antagonistic Activity against Fusarium solani

“…Chemical pesticides are still commonly used in strawberry cultivation to suppress F. solani [34,35]. The scant research available limits the ability of strawberry growers to choose effective products and increases the risk of generating strains resistant to the active principles used in fungicides [36]; therefore, this study examined the compatibility between biological and chemical control. T. harzianum showed high compatibility (100%) with the fungicide Captan at 450, 900, and 1350 mg L −1 ; medium compatibility (75%) with the fungicide Mancozeb at 450, 900, and 1350 mg L −1 , and low compatibility (50%) with the fungicide Chlorothalonil at 450 mg L −1 .…”

“…Chemical pesticides are still commonly used in strawberry cultivation to suppress F. solani [34,35]. The scant research available limits the ability of strawberry growers to choose effective products and increases the risk of generating strains resistant to the active principles used in fungicides [36]; therefore, this study examined the compatibility between biological and chemical control.…”

Artificial infection with Fusarium solani f.sp. passiflorae in plants of passion fruit under controlled conditions

“…Martínez-Lemus et al-Artificial Fusarium Infection in Passion fruit significant disease affecting productive passion fruit plants. As plants mature, specific conditions linked to fungal extracellular enzymatic activity (Robledo et al, 2017) facilitate the initiation of colonization and infection in the root system and/or stem base. This triggers the development of characteristic aerial symptoms of the disease, ultimately leading to plant death (Ploetz, 1991;Ploetz, 2005;Porter et al, 2015).…”