scholarly journals Evaluation of the Genetic Structure of Xylella fastidiosa Populations from Different Citrus sinensis Varieties

2002 ◽  
Vol 68 (8) ◽  
pp. 3731-3736 ◽  
Author(s):  
Helvécio Della Coletta-Filho ◽  
Marcos Antonio Machado
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Citrus Sinensis ◽  
Germ Plasm ◽  
Sweet Orange ◽  
Xylella Fastidiosa ◽  
Random Amplified Polymorphic Dna ◽  
Variable Number ◽  
Chlorosis Resistance ◽  
Northwest Region

ABSTRACT Xylella fastidiosa was isolated from sweet orange plants (Citrus sinensis) grown in two orchards in the northwest region of the Brazilian state of São Paulo. One orchard was part of a germ plasm field plot used for studies of citrus variegated chlorosis resistance, while the other was an orchard of C. sinensis cv. Pêra clones. These two collections of strains were genotypically characterized by using random amplified polymorphic DNA (RAPD) and variable number of tandem repeat (VNTR) markers. The genetic diversity (HT ) values of X. fastidiosa were similar for both sets of strains; however, HT RAPD values were substantially lower than HT VNTR values. The analysis of six strains per plant allowed us to identify up to three RAPD and five VNTR multilocus haplotypes colonizing one plant. Molecular analysis of variance was used to determine the extent to which population structure explained the genetic variation observed. The genetic variation observed in the X. fastidiosa strains was not related to or dependent on the different sweet orange varieties from which they had been obtained. A significant amount of the observed genetic variation could be explained by the variation between strains from different plants within the orchards and by the variation between strains within each plant. It appears, therefore, that the existence of different sweet orange varieties does not play a role in the population structure of X. fastidiosa. The consequences of these results for the management of sweet orange breeding strategies for citrus variegate chlorosis resistance are also discussed.

scholarly journals Populational fluctuation of vectors of Xylella fastidiosa, wells in sweet orange [Citrus sinensis (L.) Osbeck] varieties of northwest Paraná State, Brazil

2010 ◽  
Vol 53 (3) ◽  
pp. 549-554 ◽  
Author(s):  
Rúbia de Oliveira Molina ◽  
Aline Maria Orbolato Gonçalves ◽  
Carlos Alexandre Zanutto ◽  
William Mário de Carvalho Nunes
Keyword(s):  
Citrus Sinensis ◽  
Sweet Orange ◽  
Xylella Fastidiosa ◽  
Northwest Region

The aim of the present study was to assess the population flutuation of the sharpshooters species subfamily Cicadellinae belonging to the tribes Cicadellini and Proconiini, in sweet orange [Citrus sinensis( L). Osbeck] commercial orchards of the northwest region of Paraná State , Brazil. Samplings were carried out the employing every time 24 yellow sticky cards. Identification of the species showed that the most representative were Dilobopterus costalimai of the Cicadellini tribe and Acrogonia citrina of the Proconiini tribe.

Aspects of Xylella fastidiosa Xylem Vessel Colonization of Sweet Orange (Citrus sinensis (L. Osbeck) Cultivar "Péra", Revealed by Electron Microscopy.

2004 ◽  
Vol 10 (S02) ◽  
pp. 1452-1453 ◽  
Author(s):  
Eduardo Alves ◽  
Breno Leite
Keyword(s):  
Electron Microscopy ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Xylella Fastidiosa ◽  
Xylem Vessel

Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.

scholarly journals Genetic diversity and population structure of sweet orange [Citrus sinensis (L.) Osbeck] germplasm of India revealed by SSR and InDel markers

2022 ◽  
Author(s):  
Prasanth Tej Kumar Jagannadham ◽  
Thirugnanavel Anbalagan ◽  
Devendra Y Upadhyay ◽  
Snehal A. Kamde ◽  
Prafulla R. Jalamkar ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Polymorphic Information Content ◽  
Citrus Fruit ◽  
Molecular Data ◽  
Expected Heterozygosity ◽  
Indel Markers ◽  
Population Structure Analysis

Sweet orange (Citrus sinensis (L.) Osbeck) is an important commercial citrus fruit crop, cultivated in India and across the world. In India most of the cultivated sweet orange species were introduced varieties. In this study, we used two molecular markers, SSR and InDels, to understand the genetic diversity and population structure of seventy-two sweet orange genotypes. Genetic parameters consisted of a total number of alleles, a number of polymorphic alleles (effective alleles); genetic diversity (G.D.), expected heterozygosity (He), and the polymorphic information content (PIC) were calculated based on molecular data. Two dendrograms were constructed based on the InDels and SSR. In both the cases, they formed three major clusters showing various degrees of variations with respect to members of the clusters. Population structure analysis revealed the presence of two distinct subpopulations. Therefore, in order to address various challenges and develop sweet orange varieties with desirable traits, there is a need to broaden the genetic base of sweet orange through the intensive collection in the northeastern region. These results of intraspecific genetic variability of the collections will dictate the path for the sweet orange breeding and conservation programs in India.

scholarly journals Multiplication and Movement of a Citrus Strain of Xylella fastidiosa Within Sweet Orange

Plant Disease ◽  
2001 ◽  
Vol 85 (4) ◽  
pp. 382-386 ◽  
Author(s):  
R. P. P. Almeida ◽  
E. F. Pereira ◽  
A. H. Purcell ◽  
J. R. S. Lopes
Keyword(s):  
Citrus Sinensis ◽  
Sweet Orange ◽  
Xylella Fastidiosa ◽  
Population Estimates ◽  
Cell Populations ◽  
Systemic Movement ◽  
Foliar Symptoms ◽  
Inoculation Site ◽  
Citrus Groves ◽  
Leaf Veins

Populations of cultivable cells of a citrus variegated chlorosis (CVC) disease strain of Xylella fastidiosa in stems and leaf veins of sweet orange (Citrus sinensis (L.) Osbeck) seedlings were estimated by dilution plating at 1, 2, 4, 8, and 16 weeks after needle inoculation. Cell populations ranged from log 4 to log 5 CFU/g of tissue after 1 week and increased to log 5 to log 7 CFU/g (median log 6) after 8 to 16 weeks. Recovery of greater than log 5 CFU/g from stem nodes distal to the inoculation site indicated systemic movement of the bacteria. Foliar symptoms in inoculated seedlings first appeared after 8 weeks. Population estimates from leaf veins of CVC-affected trees in citrus groves were in the same range but slightly lower (average log 5.8 CFU/g). X. fastidiosa was isolated from citrus more efficiently in periwinkle wilt-GelRite (PWG) and periwinkle wilt (PW) media than in charcoal-yeast extract with ACES buffer (BCYE) medium The relatively lower populations of cultivable cells of X. fastidiosa in citrus with CVC symptoms, compared with those reported in grapevines with Pierce's disease, suggest that most cells of X. fastidiosa within symptomatic citrus may be dead, explaining in part the low rates of vector transmission from citrus to citrus.

scholarly journals Population Biology of Pseudoperonospora humuli in Oregon and Washington

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1283-1286 ◽  
Author(s):  
Hee Youn Chee ◽  
Mark E. Nelson ◽  
Gary G. Grove ◽  
Kenneth C. Eastwell ◽  
Stephen T. Kenny ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Population Biology ◽  
Random Amplified Polymorphic Dna ◽  
Dna Amplification ◽  
Pseudoperonospora Humuli ◽  
Band Profile ◽  
Geographic Regions ◽  
Unique Band

Pseudoperonospora humuli populations from Oregon and Washington were analyzed for genetic variation using random amplified polymorphic DNA (RAPD) and DNA amplification fingerprinting (DAF) markers. The genetic structure of the Oregon and Washington populations differed considerably. There was little genetic diversity in Washington, with only five RAPD and six DAF groups detected among 40 isolates tested. One genotype was predominant in Washing-ton. In contrast, 18 RAPD and 34 DAF groups were found among the 40 isolates tested from Oregon. No unique band profile associated with host cultivar was observed. It is suggested that the distinct difference in population structure between the two geographic regions might be due to climatic differences resulting in a higher frequency of sexual reproduction of P. humuli in Oregon than in Washington.

scholarly journals Citrus sinensis leaf petiole and blade colonization by Xylella fastidiosa: details of xylem vessel occlusion

2009 ◽  
Vol 66 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Eduardo Alves ◽  
Breno Leite ◽  
Sérgio Florentino Pascholati ◽  
Maria Lúcia Ishida ◽  
Peter Craig Andersen
Keyword(s):  
Electron Microscopy ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Xylella Fastidiosa ◽  
Amorphous Material ◽  
Infected Plant ◽  
Bacterial Cells ◽  
Vessel Occlusion ◽  
Leaf Petiole ◽  
Pit Membrane

Citrus variegated chlorosis (CVC), caused by Xylella fastidiosa, is an important disease of citrus in Brazil. X. fastidiosa is restricted to xylem vessels of plants and knowledge regarding xylem colonization is still limited. Our goal was to verify how this bacterium colonizes and spreads within xylem vessels of sweet orange Citrus sinensis cv. Pêra. Petioles and pieces of leaf blades from naturally infected plant exhibiting characteristic symptoms were prepared for light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and immunogold labeling (IGL). Petioles from healthy plants were used as control. IGL results, using an antibody against wall hemicelluloses, revealed that the pit membrane of vessels was altered. Bacterial cells were observed in the pit between adjacent vessels. Results support the contention that X. fastidiosa produces cellulases to reach adjacent vessels. SEM revealed that colonization of sweet orange started with X. fastidiosa cells attaching to the xylem wall, followed by an increase in the number of bacterial cells, the production of fibrous material, and finally vessel occlusion by biofilm composed of copious amounts of amorphous material, strands and cells. Phenolic materials, hyperplasia and hypertrophy were noticed in leaves with gummy material. Xylem vessels frequently contained an unknown needle-like, crystallized matter blocking the vessel.

scholarly journals Xylella fastidiosa disturbs nitrogen metabolism and causes a stress response in sweet orange Citrus sinensis cv. Pera

2007 ◽  
Vol 58 (11) ◽  
pp. 2733-2744 ◽  
Author(s):  
R. P. Purcino ◽  
C. L. Medina ◽  
D. M. de Souza ◽  
F. V. Winck ◽  
E. C. Machado ◽  
...  
Keyword(s):  
Stress Response ◽  
Nitrogen Metabolism ◽  
Citrus Sinensis ◽  
Sweet Orange ◽  
Xylella Fastidiosa

scholarly journals Geographical Genetic Structure of Xylella fastidiosa from Citrus in São Paulo State, Brazil

2003 ◽  
Vol 93 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Helvécio Della Coletta-Filho ◽  
Marcos Antonio Machado
Keyword(s):  
Genetic Structure ◽  
Genetic Differentiation ◽  
Xylella Fastidiosa ◽  
Random Amplified Polymorphic Dna ◽  
Variable Number Tandem Repeat ◽  
Geographic Region ◽  
Sao Paulo ◽  
Variable Number ◽  
São Paulo ◽  
Mean Values

A total of 360 Xylella fastidiosa strains were isolated from sweet orange (Citrus sinensis) cv. Pera plants growing in five geographic regions in the Brazilian state of São Paulo. The genetic variation of these strains was determined by 15 variable number tandem repeat (VNTR) and 58 random amplified polymorphic DNA (RAPD) markers. The mean values of genetic diversity (H) of X. fastidiosa strains within each geographic region determined by RAPD (HRAPD) were substantially lower than HVNTR values. HRAPD values ranged from 0.00 to 0.095, whereas the HVNTR values ranged from 0.024 to 0.285. A highly significant value of Nei's coefficient of gene differentiation (GST = 0.355; P = 0.000) was detected among all five populations. Analysis of the molecular variance (AMOVA) also revealed significant genetic differentiation among regions or populations ( φSTAT = 0.810; P< 0.001). In addition, genetic differentiation among subpopulations (plants) within the regions (φSTAT = 0.699; P < 0.001) and within each plant (φSTAT = 368; P < 0.001) were statistically significant. These high values of genetic differentiation among X. fastidiosa strains from different regions suggest a genetic structure according to region of host origin. However, no apparent correlation between genetic distance and region of origin of populations were supported statistically by Mantel analysis (r = 0.27; P = 0.22).

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