scholarly journals Phenotypic Characterization of Genetically Distinct Phytophthora cinnamomi Isolates from Avocado

2019 ◽  
Vol 109 (3) ◽  
pp. 384-394 ◽  
Author(s):  
Rodger J. Belisle ◽  
Brandon McKee ◽  
Wei Hao ◽  
Margaret Crowley ◽  
Mary Lu Arpaia ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mycelial Growth ◽  
Phytophthora Cinnamomi ◽  
Phenotypic Characterization ◽  
Breeding Programs ◽  
Fungicide Sensitivity ◽  
Phytophthora Root Rot ◽  
Mycelial Growth Rate ◽  
Potassium Phosphite

Phytophthora cinnamomi, the causal agent of Phytophthora root rot (PRR), is the most destructive disease of avocado worldwide. A previous study identified two genetically distinct clades of A2 mating type avocado isolates in California; however, the phenotypic variation among them was not assessed. This study described the phenotype of a subset of isolates from these groups regarding growth rate, growth temperature, virulence, and fungicide sensitivity. Isolates corresponding to the A2 clade I group exhibited higher mycelial growth rate and sensitivity to higher temperatures than other isolates. Among the fungicides tested, potassium phosphite had the highest 50% effective concentration for mycelial growth inhibition and oxathiapiprolin had the lowest. Mycelial growth rate and potassium phosphite sensitivity phenotypes correlate with specific groups of isolates, suggesting that these traits could be a group characteristic. Moreover, isolates that are more virulent in avocado and less sensitive to potassium phosphite were identified. A detached-leaf P. cinnamomi inoculation method using Nicotiana benthamiana was developed and validated, providing an alternative method for assessing the virulence of a large number of isolates. This information will help avocado PRR management and assist breeding programs for the selection of rootstocks resistant against a more diverse pathogen population.

scholarly journals Identification and characterization of pathogenic Pestalotiopsis species to pecan tree in Brazil

2014 ◽  
Vol 49 (6) ◽  
pp. 440-448 ◽  
Author(s):  
Marília Lazarotto ◽  
Marciéli Pitorini Bovolini ◽  
Marlove Fátima Brião Muniz ◽  
Ricardo Harakawa ◽  
Lia Rejane Silveira Reiniger ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mycelial Growth ◽  
Its Region ◽  
Morphological Characters ◽  
Morphological Characterization ◽  
Identification Methods ◽  
Initial Separation ◽  
Mycelial Growth Rate ◽  
Pathogenicity Tests

The objective of this work was to characterize and cluster isolates of Pestalotiopsis species and to identify those that are pathogenic to pecan, based on morphological and molecular characters. Pestalotiopsis spp. isolates were identified by sequencing the internal transcribed spacer (ITS) and β?tubulin regions. Identification methods were compared to indicate the key morphological characters for species characterization. Thirteen isolates were used for the pathogenicity tests. Morphological characterization was performed using the following variables: mycelial growth rate, sporulation, colony pigmentation, and conidial length and width. Ten pathogenic isolates were identified, three as -tubulin regions. Identification methods were compared to indicate the key morphological characters for species characterization. Thirteen isolates were used for the pathogenicity tests. Morphological characterization was performed using the following variables: mycelial growth rate, sporulation, colony pigmentation, and conidial length and width. Ten pathogenic isolates were identified, three as Pestalotiopsis clavispora and three as P. cocculi. The other isolates remained as an undefined species. The morphological characters were efficient for an initial separation of the isolates, which were grouped according to differences at species level, mainly colony diameter, which was identified as an important morphological describer. Beta-tubulin gene sequencing was less informative than the ITS region sequencing for species identification.

scholarly journals Morphology and mycelial growth rate of Pleurotus spp. strains from the Mexican mixtec region

2014 ◽  
Vol 45 (3) ◽  
pp. 861-872 ◽  
Author(s):  
P.C. Guadarrama-Mendoza ◽  
G. Valencia del Toro ◽  
R. Ramírez-Carrillo ◽  
F. Robles-Martínez ◽  
J. Yáñez-Fernández ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mycelial Growth ◽  
Mycelial Growth Rate

scholarly journals Phenotypic diversity and carcass quality of creole goats with genetic potential for resistance to infection caused by worm

2018 ◽  
Vol 53 (7) ◽  
pp. 849-857
Author(s):  
Vanessa dos Santos Neri ◽  
José Lindenberg Rocha Sarmento ◽  
Laylson da Silva Borges ◽  
Tatiana Saraiva Torres ◽  
Luciano Silva Sena ◽  
...  
Keyword(s):  
Body Weight ◽  
Phenotypic Diversity ◽  
Phenotypic Characterization ◽  
Carcass Quality ◽  
Breeding Programs ◽  
Genetic Groups ◽  
Genetic Potential ◽  
Resistance To Infection

Abstract: The objective of this work was to phenotypically characterize creole goats of the Moxotó, Azul, Canindé, Repartida, Marota, and Graúna breeds, comparing them with the Boer, Anglo Nubian, and Alpine exotic breeds, to identify the genetic groups of greater potential for carcass quality and resistance to infection caused by worm. Data on morphometric measurements were obtained for the count of worm eggs in grams of feces (WEGF), Famacha score, carcass measurements, and body weight from 308 animals, in a farm in the state of Piauí, Brazil. Repartida goats showed the highest average for wither height (61.55 cm) and rump height (62.16 cm), and Moxotó goats had the greatest ear length (13.45 cm). The Moxotó breed showed the highest means for carcass and body weight. The lowest average for body weight was observed in Azul goats (24.35 kg), and the lowest WEGF was detected in Repartida goats (200 eggs per gram of feces). The average Famacha score was 2.77. Average linkage was the method that best summarized the information on the morphometric and carcass data. The use of morphometric and carcass measurements provides satisfactory results in the phenotypic characterization of the animals. The Brazilian creole goats, which are considered resistant to worm infection and show high-quality carcass traits, may be indicated for conservation and genetic breeding programs.

scholarly journals Characterization and fungicides sensitivity of Phytophthora cinnamomi isolates causing avocado root rot in Zitácuaro, Michoacán

2021 ◽  
Vol 40 (1) ◽  
Author(s):  
Alejandra Mondragón-Flores ◽  
Patricia Manosalva ◽  
Salvador Ochoa-Ascencio ◽  
Marlene Díaz-Celaya ◽  
Gerardo Rodríguez-Alvarado ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mating Type ◽  
Root Rot ◽  
Phytophthora Cinnamomi ◽  
Potassium Phosphite ◽  
Pathogenicity Tests

<em>Phytophthora cinnamomi</em> is the pathogen most frequently associated with avocado root rot. In Zitácuaro, Michoacán, production has increased by 19.8%; however, there are no studies of root rot in this area. The objective of the study was to characterize the isolates obtained from avocado roots and assess the sensitivity to fungicides. Samples from 5 avocado orchards were collected, sampling 5 trees per orchard (a total of 25 samples). The samples isolated were characterized morphological and molecularly. Mating type was analyzed using reference isolates of<em> P. cinnamomi</em> A1 (isolate from camelia) and A2 (isolate from avocado). To confirm the pathogenicity, tests were performed on avocado fruits with the isolates. The sensitivity of 15 isolates to potassium phosphite and to metalaxyl-M at different concentrations was evaluated<em> in vitro</em>. In a subgroup of six isolates, it was evaluated whether there was a relationship between growth rate and potassium phosphite sensitivity. Fifteen isolates were obtained with coenocytic coraloid mycelium, chlamydospores, sporangia without papilla, ovoid to ellipsoid, with internal proliferation, heterothallic with mating type A2, with amphigynous antheridia and plerotic oospores, characteristics consistent with <em>P. cinnamomi</em>. The inoculated isolates were pathogenic on avocado fruits. The isolates were more sensitive to potassium phosphite than to metalaxyl-M, with mean EC50 values of 24.62 and 0.215 ?g mL-1 of i.a., respectively. No relationship was observed between growth rate and potassium phosphite sensitivity. It is necessary to obtain a greater number of<em> P. cinnamomi</em> isolates for virulence studies.

scholarly journals Antagonism of Plant Pathogens by Calotropis procera

2021 ◽  
Vol 13 (4) ◽  
pp. 120
Author(s):  
Karla Danielle Nogueira Cardoso ◽  
Maria Josiane Martins ◽  
Thaisa Aparecida Neres de Souza ◽  
Isabelle Carolyne Cardoso ◽  
Patrícia Nirlane da Costa Souza ◽  
...  
Keyword(s):  
Growth Rate ◽  
Aqueous Extract ◽  
Mycelial Growth ◽  
Plant Pathogens ◽  
Calotropis Procera ◽  
Mycelial Growth Rate ◽  
Vitro Effect ◽  
Fungal Colony

Phomopsis sojae and Sclerotinia sclerotiorum are responsible for stem and pod dryness and white mold in soybean. These pathologies directly affect the quality of seeds/grains and compromise the entire plant. The use of extracts from different plants has been the subject of research for the control of several phytopathogens. Calotropis procera is among botanical species that synthesize efficient compounds for biocontrol. In this context, the aim of this study was to evaluate the in vitro effect of C. procera aqueous extract on P. sojae and S. sclerotiorum. The experiment was carried out in completely randomized blocks in a 2 &times; 5 factorial scheme (two fungi and five extract concentrations 0%, 5%, 10%, 15% and 20%) with 4 replicates. C. procera aqueous extract concentrations were added to Petri dishes containing PDA. After 48 hours, the mycelial growth rate was evaluated. After seven days of incubation, the fungal colony area, sporulation, and germination of P. sojae and S. sclerotiorum were evaluated. There was significant interaction between fungi &times; extract concentrations (p &lt; 0.05) for all variables analyzed. The mycelial growth rate of P. sojae was lower than that of S. sclerotiorum. The diameter of the P. sojae fungal colony was smaller than that of S. sclerotiorum when concentrations of 5%, 10% and 15% were used. As the extract concentration increased, fungi sporulation and germination reduced.

scholarly journals Mycelial inhibition of Trichoderma spp. isolated from the cultivation of Pleurotus ostreatus with an extract of Pycnoporus sp.

2020 ◽  
Author(s):  
Anaid Talavera-Ortiz ◽  
Priscila Chaverri ◽  
Gerardo Diaz-Godinez ◽  
Ma de Lourdes Acosta-Urdapilleta ◽  
Elba Villegas ◽  
...  
Keyword(s):  
Growth Rate ◽  
Pleurotus Ostreatus ◽  
Mycelial Growth ◽  
Viral Diseases ◽  
Human Consumption ◽  
Edible Fungi ◽  
Lignocellulosic Substrate ◽  
Trichoderma Spp ◽  
Mycelial Growth Rate ◽  
The One

Abstract:Background and Aims: The production of edible fungi is affected by bacterial, fungal and viral diseases, which very often cause large losses. In the productionof mushrooms of the genus Pleurotus, the fungi of Trichoderma spp. represent a serious problem of contamination and although there are some chemical compoundsthat control the infection, they are not entirely safe for human consumption. As a consequence, alternatives are being searched for through biotechnology,such as the one presented in this paper.Methods: Strains of fungi of the genus Trichoderma were isolated from the substrate where Pleurotus ostreatus was being cultivated. These were identifiedmorphologically and molecularly, followed by tests to inhibit the growth of Trichoderma strains in both agar and wheat straw, using a cetonic extract of thedehydrated fruiting body of Pycnoporus sp.Key results: Two strains of Trichoderma (T. pleuroti and T. atrobrunneum, belonging to the clade of T. harzianum) were isolated from infected substrate obtainedin production modules of Pleurotus ostreatus located in Tlaquitenango and Cuernavaca, in the state of Morelos, Mexico. The effect of a cetonic extract of thefruiting body of Pycnoporus sp. on the mycelial growth of the isolated strains of Trichoderma was also evaluated, observing decrease in mycelial growth rate inPetri dish up to 72% and on lignocellulosic substrate both mycelial growth and sporulation were delayed up to 10 days.Conclusions: The extract of Pycnoporus sp. could be an alternative to control the infection by Trichoderma spp. in mushroom cultures of the genus Pleurotus.Key words: disease control, edible mushrooms, lignocellulosic substrate. 

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