Study of a new biocontrol fungal agent for avocado white root rot

Arjona-Girona, Isabel; López‐Herrera, C. J.

doi:10.1016/j.biocontrol.2017.08.018

Cited by 17 publications

(8 citation statements)

References 17 publications

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“…Sampling locations, years of isolation, host plants and references of the isolates are summarized in Supporting Information Table S1. Sixty‐two Spanish isolates were largely isolated during the period from 1986 to 2017 from southern provinces such as Malaga and Granada, and some were described earlier (López‐Herrera and Zea‐Bonilla, ; Pliego et al ., ; Arjona‐Girona and López‐Herrera, ). Sixteen Israeli isolates were largely isolated during a period of years 2011–2013 from apple and cherry trees in the Galilee and the Golan Heights in the northern part of Israel (Dafny Yelin et al ., ).…”

Section: Methodsmentioning

confidence: 99%

Novel, diverse RNA viruses from Mediterranean isolates of the phytopathogenic fungus, Rosellinia necatrix: insights into evolutionary biology of fungal viruses

Arjona-López

Telengech

Jamal

et al. 2018

Environmental Microbiology

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To reveal mycovirus diversity, we conducted a search of as-yet-unexplored Mediterranean isolates of the phytopathogenic ascomycete Rosellinia necatrix for virus infections. Of seventy-nine, eleven fungal isolates tested RNA virus-positive, with many showing coinfections, indicating a virus incidence of 14%, which is slightly lower than that (approximately 20%) previously reported for extensive surveys of over 1000 Japanese R. necatrix isolates. All viral sequences were fully or partially characterized by Sanger and next-generation sequencing. These sequences appear to represent isolates of various new species spanning at least 6 established or previously proposed families such as Partiti-, Hypo-, Megabirna-, Yado-kari-, Fusagra- and Fusarividae, as well as a newly proposed family, Megatotiviridae. This observation greatly expands the diversity of R. necatrix viruses, because no hypo-, fusagra- or megatotiviruses were previously reported from R. necatrix. The sequence analyses showed a rare horizontal gene transfer event of the 2A-like protease domain between a dsRNA (phlegivirus) and a positive-sense, single-stranded RNA virus (hypovirus). Moreover, many of the newly detected viruses showed the closest relation to viruses reported from fungi other than R. necatrix, such as Fusarium spp., which are sympatric to R. necatrix. These combined results imply horizontal virus transfer between these soil-inhabitant fungi.

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Section: Methodsmentioning

confidence: 99%

Novel, diverse RNA viruses from Mediterranean isolates of the phytopathogenic fungus, Rosellinia necatrix: insights into evolutionary biology of fungal viruses

Arjona-López

Telengech

Jamal

et al. 2018

Environmental Microbiology

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“…GARD analysis using AIC c score resulted in a possible breakpoint at position 501 (LHS P -value = 0.038). There is no correlation between the origin of the strains and the genetic identity (for details on the location of the trees see Arjona-Girona and López-Herrera, 2018 ). Besides, in each orchard and even in each tree, strains can belong to different clades.…”

Section: Resultsmentioning

confidence: 99%

“…Thirty-nine fungal isolates (20 Entoleuca sp. and 19 R. necatrix ) were collected from avocado escape trees of four orchards located in the Malaga province (Spain) spanning along a track of 35 km ( Arjona-Girona and López-Herrera, 2018 ). These plants were surrounded by white root rot symptomatic avocado trees.…”

Section: Methodsmentioning

confidence: 99%

“…Differentiation between R. necatrix and Entoleuca sp. was based on sequencing of the genomic ITS region amplified with ITS4 and ITS5 primers ( Arjona-Girona and López-Herrera, 2018 ).…”

Section: Methodsmentioning

confidence: 99%

“…Therefore, Entoleuca sp. has been recently proposed as a biocontrol agent of white root rot in avocado ( Arjona-Girona and López-Herrera, 2018 ). On the other hand, we found that Entoleuca sp.…”

Section: Introductionmentioning

confidence: 99%

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A Novel Hypovirus Species From Xylariaceae Fungi Infecting Avocado

et al. 2018

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The white rot root disease caused by Rosellinia necatrix is a major concern for avocado cultivation in Spain. Healthy escapes of avocado trees surrounded by diseased trees prompted us to hypothesize the presence of hypovirulent R. necatrix due to mycovirus infections. Recently, we reported the presence of another fungal species, Entoleuca sp., belonging to the Xylariaceae, that was also found in healthy avocado trees and frequently co-infecting the same roots than R. necatrix. We investigated the presence of mycoviruses that might explain the hypovirulence. For that, we performed deep sequencing of dsRNAs from two isolates of Entoleuca sp. that revealed the simultaneous infection of several mycoviruses, not described previously. In this work, we report a new member of the Hypoviridae, tentatively named Entoleuca hypovirus 1 (EnHV1). The complete genome sequence was obtained for two EnHV1 strains, which lengths resulted to be 14,958 and 14,984 nt, respectively, excluding the poly(A) tails. The genome shows two ORFs separated by a 32-nt inter-ORF, and both 5′- and 3′-UTRs longer than any other hypovirus reported to date. The analysis of virus-derived siRNA populations obtained from Entoleuca sp. demonstrated antiviral silencing activity in this fungus. We screened a collection of Entoleuca sp. and R. necatrix isolates and found that EnHV1 was present in both fungal species. A genetic population analysis of EnHV1 strains revealed the presence of two main clades, each of them including members from both Entoleuca sp. and R. necatrix, which suggests intra- and interspecific virus transmission in the field. Several attempts failed to cure Entoleuca sp. from EnHV1. However, all Entoleuca sp. isolates collected from avocado, whether harboring the virus or not, showed hypovirulence. Conversely, all R. necatrix isolates were pathogenic to that crop, regardless of being infected by EnHV1.

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