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Genetic diversity and population differentiation of the causal agent of citrus black spot in Brazil.

Wickert E, de Goes A, de Souza A, Lemos EG - ScientificWorldJournal (2012)

Bottom Line: This disease causes irreparable losses due to the premature falling of fruit, as well as its severe effects on the epidermis of ripe fruit that renders them unacceptable at the fresh fruit markets.The objective of this work was study the genetic diversity and population differentiation of G. citricarpa associated with four sweet orange varieties in two geographic locations using DNA sequence of ITS1-5.8S-ITS2 region from fungi isolates.If new and pathogenic fungi would become resistant to fungicides, the observed genetic structure could rapidly spread this new form from one population to others.

View Article: PubMed Central - PubMed

Affiliation: Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina-EPAGRI, Estação Experimental de Itajaí, Rodovia Antônio Heil 8400, Itaipava, 88318-112 Itajaí, SC, Brazil. esterwickert@epagri.sc.gov.br

ABSTRACT
One of the most important diseases that affect sweet orange orchards in Brazil is the Citrus Black Spot that is caused by the fungus Guignardia citricarpa. This disease causes irreparable losses due to the premature falling of fruit, as well as its severe effects on the epidermis of ripe fruit that renders them unacceptable at the fresh fruit markets. Despite the fact that the fungus and the disease are well studied, little is known about the genetic diversity and the structure of the fungi populations in Brazilian orchards. The objective of this work was study the genetic diversity and population differentiation of G. citricarpa associated with four sweet orange varieties in two geographic locations using DNA sequence of ITS1-5.8S-ITS2 region from fungi isolates. We observed that different populations are closely related and present little genetic structure according to varieties and geographic places with the highest genetic diversity distributed among isolates of the same populations. The same haplotypes were sampled in different populations from the same and different orange varieties and from similar and different origins. If new and pathogenic fungi would become resistant to fungicides, the observed genetic structure could rapidly spread this new form from one population to others.

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Related in: MedlinePlus

Aspects of G. citricarpa colony morphology in oatmeal medium (left), showing the yellow halo, characteristic for pathogenic isolates, and its aspect on PDA medium, without halo.
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fig1: Aspects of G. citricarpa colony morphology in oatmeal medium (left), showing the yellow halo, characteristic for pathogenic isolates, and its aspect on PDA medium, without halo.

Mentions: All 384 Guignardia isolates submitted to characterisation in oatmeal media showed a yellow halo around the colonies (Figure 1) that is indicative of the G. citricarpa species, pathogenic to citrus plants [2, 8]. This method thereby ensures that all isolates of this study effectively belong to the G. citricarpa species.


Genetic diversity and population differentiation of the causal agent of citrus black spot in Brazil.

Wickert E, de Goes A, de Souza A, Lemos EG - ScientificWorldJournal (2012)

Aspects of G. citricarpa colony morphology in oatmeal medium (left), showing the yellow halo, characteristic for pathogenic isolates, and its aspect on PDA medium, without halo.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3362019&req=5

fig1: Aspects of G. citricarpa colony morphology in oatmeal medium (left), showing the yellow halo, characteristic for pathogenic isolates, and its aspect on PDA medium, without halo.
Mentions: All 384 Guignardia isolates submitted to characterisation in oatmeal media showed a yellow halo around the colonies (Figure 1) that is indicative of the G. citricarpa species, pathogenic to citrus plants [2, 8]. This method thereby ensures that all isolates of this study effectively belong to the G. citricarpa species.

Bottom Line: This disease causes irreparable losses due to the premature falling of fruit, as well as its severe effects on the epidermis of ripe fruit that renders them unacceptable at the fresh fruit markets.The objective of this work was study the genetic diversity and population differentiation of G. citricarpa associated with four sweet orange varieties in two geographic locations using DNA sequence of ITS1-5.8S-ITS2 region from fungi isolates.If new and pathogenic fungi would become resistant to fungicides, the observed genetic structure could rapidly spread this new form from one population to others.

View Article: PubMed Central - PubMed

Affiliation: Empresa de Pesquisa Agropecuária e Extensão Rural de Santa Catarina-EPAGRI, Estação Experimental de Itajaí, Rodovia Antônio Heil 8400, Itaipava, 88318-112 Itajaí, SC, Brazil. esterwickert@epagri.sc.gov.br

ABSTRACT
One of the most important diseases that affect sweet orange orchards in Brazil is the Citrus Black Spot that is caused by the fungus Guignardia citricarpa. This disease causes irreparable losses due to the premature falling of fruit, as well as its severe effects on the epidermis of ripe fruit that renders them unacceptable at the fresh fruit markets. Despite the fact that the fungus and the disease are well studied, little is known about the genetic diversity and the structure of the fungi populations in Brazilian orchards. The objective of this work was study the genetic diversity and population differentiation of G. citricarpa associated with four sweet orange varieties in two geographic locations using DNA sequence of ITS1-5.8S-ITS2 region from fungi isolates. We observed that different populations are closely related and present little genetic structure according to varieties and geographic places with the highest genetic diversity distributed among isolates of the same populations. The same haplotypes were sampled in different populations from the same and different orange varieties and from similar and different origins. If new and pathogenic fungi would become resistant to fungicides, the observed genetic structure could rapidly spread this new form from one population to others.

Show MeSH
Related in: MedlinePlus