Analysis of the Fungal Diversity in Citrus Leaves with Greasy Spot Disease Symptoms

Abdelfattah, Ahmed; Cacciola, S. O.; Mosca, Saveria; Zappia, Rocco; Schena, Leonardo

doi:10.1007/s00248-016-0874-x

Cited by 29 publications

(20 citation statements)

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“…The consensus of the olive community composition described herein, including the proportion of the fungal taxa at all the taxonomical levels (from phyla to genera) is in strong agreement with the previous description of the olive fungal community; being dominated by fungal genera such as Aureobasidium , Cladosporium , and Alternaria (14). The stability of the olive fungal community in the investigated samples in the present and in a previous study (14), and how they differ remarkably from other hosts (21) (30) (21), confirms that the microbial community is determined primarily by its host identity. Interestingly, non-pathogenic fungal species such as Aureobasidium pullulans were largely prevalent in all localities.…”

Section: Discussionsupporting

confidence: 84%

Impact of Bactrocera oleae on the fungal microbiota of ripe olive drupes

Abdelfattah

Ruano-Rosa

Cacciola

et al. 2018

Preprint

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37 The olive fruit fly (OFF), Bactrocera oleae is the most devastating pest affecting olive fruit 38 worldwide. Previous investigations have addressed the fungal microbiome associated with olive 39 drupes or B. oleae, but the impact of the insect on fungal communities of olive fruit remains 40 undescribed. In the present work, the fungal microbiome of olive drupes, infested and non-infested 41 by the OFF, was investigated in four different localities and cultivars. Olive fruit fly infestations 42 caused a general reduction of the fungal diversity, a higher quantity of the total DNA and an 43 increase in taxa that remained unidentified or had unknown roles. The infestations led to imbalanced 44 fungal communities with the growth of taxa that are usually outcompeted. While it was difficult to 45 establish a cause-effect link between fly infestation and specific fungi, it is clear that the fly alters 46 the natural microbial balance, especially the low abundant taxa. On the other hand, the most 47 abundant ones, were not significantly influenced by the insect. In fact, despite the slight variation 48 between the sampling locations, Aureobasidium, Cladosporium, and Alternaria, were the dominant 49 genera, suggesting the existence of a typical olive fungal microbiome. 50 51 Keywords: Olea europaea, fungal microbiome, olive fruit fly, Bactrocera oleae, imbalanced 52 fungal communities, dysbiosis, metabarcoding analyses 53 Introduction 54 Olive (Olea europaea L.) is one of the most important cultivated crops on a global scale (1). The 55 countries of the coastal areas of the Mediterranean Basin represent the typical olive belt with more 56 than 10 million ha, accounting for about 80% of the world's total olive cultivation area (2). This 57 crop is threatened by several abiotic and biotic stresses mainly caused by insects, pathogens, and 58 nematodes (3-5). Among those, the olive fruit fly (OFF) Bactrocera oleae (Rossi) is considered the 59 most destructive key pest for olive production, and can be virtually found wherever Olea species 60 are present (6). Bactrocera oleae, in contrast to other Tephritidae Diptera, is strictly monophagous, 61 feeding exclusively on olive fruits, and has a unique ability to feed on unripe green fruits which 62 contain high levels of phenolic compounds such as oleuropein. This ability is attributed to the high 63 number of detoxifying genes activated during larvae feeding (7) as well as the presence of the 64 symbionts such as 'Candidatus Erwinia dacicola' in their gut (8). The microbiome of B. oleae has 65 been found to be essential for its survival in natural conditions and is likely to play an important 66 role on the longevity, competitiveness, and ability of the insect to cope with biotic stresses (9).67 Although the source of B. oleae microbiome is unknown, some evidence suggests a vertical 68 transmission from one generation to the next. Adult females of B. oleae, use their ovipositors to lay 98 fruits' mesocarp and exocarp were separated from the stone, which was discarded. Lyophili...

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Section: Discussionsupporting

confidence: 84%

Impact of Bactrocera oleae on the fungal microbiota of ripe olive drupes

Abdelfattah

Ruano-Rosa

Cacciola

et al. 2018

Preprint

Self Cite

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“…Interestingly, none of the detected sequences clustered with Z . citri-griseum or allied species previously associated with citrus greasy spot in other regions [ 12 ].…”

Section: Discussionmentioning

confidence: 99%

“…was associated with the disease [ 10 , 11 ]. Furthermore, recent metagenomic studies in Sicily indicated that the family Mycosphaerellaceae was the most abundant in leaves with greasy spot symptoms [ 12 ]. Symptoms of citrus greasy spot have also been observed in sweet orange in Egypt, but in this case the species Z .…”

Section: Introductionmentioning

confidence: 99%

Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain

et al. 2017

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Greasy spot of citrus, caused by Zasmidium citri-griseum (= Mycosphaerella citri), is widely distributed in the Caribbean Basin, inducing leaf spots, premature defoliation, and yield loss. Greasy spot-like symptoms were frequently observed in humid citrus-growing regions in Panama as well as in semi-arid areas in Spain, but disease aetiology was unknown. Citrus-growing areas in Panama and Spain were surveyed and isolates of Mycosphaerellaceae were obtained from citrus greasy spot lesions. A selection of isolates from Panama (n = 22) and Spain (n = 16) was assembled based on their geographical origin, citrus species, and affected tissue. The isolates were characterized based on multi-locus DNA (ITS and EF-1α) sequence analyses, morphology, growth at different temperatures, and independent pathogenicity tests on the citrus species most affected in each country. Reference isolates and sequences were also included in the analysis. Isolates from Panama were identified as Z. citri-griseum complex, and others from Spain attributed to Amycosphaerella africana. Isolates of the Z. citri-griseum complex had a significantly higher optimal growth temperature (26.8°C) than those of A. africana (19.3°C), which corresponded well with their actual biogeographical range. The isolates of the Z. citri-griseum complex from Panama induced typical greasy spot symptoms in ‘Valencia’ sweet orange plants and the inoculated fungi were reisolated. No symptoms were observed in plants of the ‘Ortanique’ tangor inoculated with A. africana. These results demonstrate the presence of citrus greasy spot, caused by Z. citri-griseum complex, in Panama whereas A. africana was associated with greasy spot-like symptoms in Spain.

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“…The analysis of the fungal community using an amplicon metagenomic approach has revealed that Mycosphaerellaceae were the dominant group of fungi, in both symptomatic and asymptomatic leaves, and were represented by the genera Ramularia, Mycosphaerella and Septoria, with about 44, 2.5 and 1.7% of the total detected sequences [39]. The most abundant sequence type was associated to Ramularia brunnea, a species originally described to cause leaf spot in a plant of the family Asteraceae.…”

Section: Citrus Pathologymentioning

confidence: 99%

Major and Emerging Fungal Diseases of Citrus in the Mediterranean Region

Khanchouch¹,

Pane²,

Chriki³

et al. 2017

Citrus Pathology

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This chapter deals with major endemic and emerging fungal diseases of citrus as well as with exotic fungal pathogens potentially harmful for citrus industry in the Mediterranean region, with particular emphasis on diseases reported in Italy and Maghreb countries. The aim is to provide an update of both the taxonomy of the causal agents and their ecology based on a molecular approach, as a preliminary step towards developing or upgrading integrated and sustainable disease management strategies. Potential or actual problems related to the intensification of new plantings, introduction of new citrus cultivars and substitution of sour orange with other rootstocks, globalization of commerce and climate changes are discussed. Fungal pathogens causing vascular, foliar, fruit, trunk and root diseases in commercial citrus orchards are reported, including Plenodomus tracheiphilus, Colletotrichum spp., Alternaria spp., Mycosphaerellaceae, Botryosphaeriaceae, Guignardia citricarpa and lignicolous basidiomycetes. Diseases caused by Phytophthora spp. (oomycetes) are also included as these pathogens have many biological, ecological and epidemiological features in common with the true fungi (eumycetes).

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Analysis of the Fungal Diversity in Citrus Leaves with Greasy Spot Disease Symptoms

Cited by 29 publications

References 50 publications

Impact of Bactrocera oleae on the fungal microbiota of ripe olive drupes

Impact of Bactrocera oleae on the fungal microbiota of ripe olive drupes

Characterization of Mycosphaerellaceae species associated with citrus greasy spot in Panama and Spain

Major and Emerging Fungal Diseases of Citrus in the Mediterranean Region

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