scholarly journals Uredospore germination of Hemileia vastatrix and its inhibition by the effect of plant extracts in vitro

2021 ◽  
Vol 48 (2) ◽  
pp. 108-117
Author(s):  
Miguel A. Morales-Antonio ◽  
◽  
Gisela M. Santiago-Martínez ◽  
Alfonso Vásquez-López ◽  
Gerardo Rodríguez-Ortiz ◽  
...  

Coffee leaf rust, caused by Hemileia vastatrix, is the most important disease of coffee (Coffea arabica L.) in Mexico. It causes production losses of up to 40% and leads to the use of considerable volumes of synthetic fungicides. The main goals of this research were to identify the temperature, pH, incubation time, and luminosity required for in vitro germination of H. vastatrix uredospores and to evaluate the effect of plant extracts on their germination. Uredospores from coffee plants (var. Caturra) grown in the state of Oaxaca, Mexico, were collected and subjected to treatments consisting of combined levels of T°, pH, and incubation time. The treatments were evaluated in darkness and under low-intensity white light (15 W). Uredospore germination occurred in the absence and presence of light. The highest percentage of uredospore germination was 44.95%, which occurred at pH 5.7, between 18 and 24 °C, and with an incubation time of 24 h. The effect of 30 plant extracts was evaluated in terms of inhibition of uredospore germination. The acetone and ethanol extracts of Tribulus terrestris, Datura ferox, Mansoa alliacea, Ricinus communis, and Acacia farnesiana inhibited 100% of uredospore germination. Thus, plant extracts may contribute to the integrated disease management of coffee leaf rust.

2021 ◽  
Vol 25 (05) ◽  
pp. 1075-1084
Author(s):  
Anayancy Lam-Gutiérrez

Hemileia vastatrix is a fungus associated with coffee leaf rust, the most destructive disease of Coffea arabica. The objective of this work was to evaluate the antifungal activity of alcoholic extracts from roots of Baccharis salicina and to determine the metabolites present in these fractions. Antifungal activity was evaluated under in vitro conditions by monitoring the germination ability of H. vastatrix, the coffee leaf rust pathogen. In order to determine the presence of metabolites, chemical characterization of fractions obtained from methanolic root extracts was performed with help of an untargeted metabolomic approach and by using high-resolution mass spectrometry (MS) and MS2 based on direct-injection electrospray mass spectrometry (DIESI-MS) and hierarchical cluster analysis (HCA). Germination percentage was evaluated by leaves fixation technique. The MEBs significantly decreased the percentage of germination of H. vastatrix to levels below 5% as the dose increased. The multivariable analysis confirmed that the distribution of three fractions of methanolic extracts belonged to polyketides, organoheterocyclic compounds, fatty acyls, prenol-lipids, organo-oxygen and farnesene classes. This report comprises the first study of the metabolomic profile and biological activity study of roots from B. salicina against coffee leaf rust pathogen H. vastatrix. © 2021 Friends Science Publishers


IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adans A. Colmán ◽  
Harry C. Evans ◽  
Sara S. Salcedo-Sarmiento ◽  
Uwe Braun ◽  
Kifle Belachew-Bekele ◽  
...  

AbstractDigitopodium hemileiae was described originally in 1930 as Cladosporium hemileiae; growing as a mycoparasite of the coffee leaf rust (CLR), Hemileia vastatrix, in a sample of diseased leaves of Coffea canephora collected in the Democratic Republic of Congo. No cultures from this material exist. More recently, the type material was re-examined and, based on morphological features, considered to be incorrectly placed in Cladosporium. The new genus Digitopodium was erected to accommodate this species. Interest in fungal antagonists of H. vastarix, as potential biocontrol agents of CLR, led to comprehensive surveys for mycoparasites, both in the African centre of origin of the rust, as well as in its South American exotic range. Among the rust specimens from Ethiopia, one was found to be colonized by a fungus congeneric with, and similar to, D. hemileiae. Pure cultures obtained from the Ethiopian material enabled a molecular study and for its phylogenetic position to be elucidated, based on DNA sequence data from the ITS and LSU regions. Molecular data showed that two members of the recently erected genus Hyalocladosporiella (Herpotrichiellaceae: Chaetothyriales) are congeneric with Digitopodium from Ethiopia and morphologically similar to both D. hemileiae and the two Ethiopian isolates. These isolates were found to be morphologically and genetically identical to H. tectonae, described previously from Brazil. Thus, species of Hyalocladosporiella are re-allocated to Digitopodium here; including D. tectonae, and a novel species, D. canescens, recently found in Brazil growing as a mycoparasite of Puccinia thaliae. The potential use of D. hemileiae and D. tectonae for classical biological control of CLR is discussed.


2021 ◽  
Vol 748 (1) ◽  
pp. 012002
Author(s):  
Sabam Malau ◽  
Albiner Siagian ◽  
Maria Rumondang Sihotang

Abstract Coffee is now experiencing a serious threat from fungus Hemileia vastatrix which caused epidemic of rust disease in America, Africa, and Asia. As solution, the use of resistant cultivars is the best way. However, interaction between genotype and environment can change the rank of genotypes that shows instability of these genotypes against leaf rust. Purpose of this research was to study stability of genotypes of Arabica coffee against coffee leaf rust. A field experiment was arranged as factorial randomized complete block design with 2 factors (genotypes and climate zones) with three replication. The observed parameters were branch rust incidence, leaf rust incidence, and leaf rust severity. This research result showed significant genotype x environment interaction in all variables. Length of dry season is the most important factor affecting coffee leaf rust because it had the highest correlation coefficient with leaf rust severity (r = 0.662**). Less length of dry season should be the first criteria for selection of coffee farms. The most desired genotype was G7 which performed low leaf rust severity (7.71%) and had a stable resistance indicated by the same leaf rust severity in all environments and 6 SMg. Due to the significant interaction between genotypes and the environment, the genotype to be planted in a region must be tested in that region first.


Botany ◽  
2010 ◽  
Vol 88 (7) ◽  
pp. 621-629 ◽  
Author(s):  
Helena Gil Azinheira ◽  
Maria do Céu Silva ◽  
Pedro Talhinhas ◽  
Clara Medeira ◽  
Isabel Maia ◽  
...  

Leaf rust, caused by Hemileia vastatrix Berk & Broome, is the most destructive fungal disease of coffee. In the absence of a suitable gene validation system in coffee, the objective of this study was to investigate whether the model plant Arabidopsis thaliana (L.) Heynh. may be used as a heterologous system for the molecular dissection of coffee responses to leaf rust. Histological examination of A. thaliana (Col-0) leaves inoculated with H. vastatrix (race II) showed that by 24 h after inoculation (hai), H. vastatrix uredospores differentiated appressoria and penetrated the stomata, but failed to form haustoria. Arabidopsis thaliana cellular resistance responses included hypersensitive-like response (HR) of stomata guard cells together with accumulation of phenolic compounds and callose deposition in walls of epidermal and mesophyll cells. Results indicate that H. vastatrix infection triggered the induction of a set of defence-related genes peaking at 18 and 42 hai. The non-host HR triggered by H. vastatrix in the model plant A. thaliana makes it usable to infer the function of coffee genes involved in pre-haustorial rust resistance.


2017 ◽  
Vol 14 (6) ◽  
pp. 1-8
Author(s):  
R Mudyiwa ◽  
N Mwatsiya ◽  
B Manenji ◽  
P Chidoko ◽  
C Mahoya

2017 ◽  
Vol 2 (3) ◽  
pp. 157-163
Author(s):  
Shivani Ghildiyal ◽  
Apurva Joshi ◽  
Vinod K Joshi

ABSTRACT Introduction Laghupanchamula is a compound formulation prepared by combinations of roots of five herbs. Two variants of Laghupanchamula have been described in Ayurvedic classics where beside four common herbs fifth one is either Gokshura (Tribulus terrestris L.) or Eranda (Ricinus communis L.). The objective of the study is to make comparison between two variants of Laghupanchmula with respect to important group of phytochemicals and antioxidant activity to corroborate the science behind their therapeutic utility. Materials and methods Standard methods have been followed for quantitative determination of total quantity of phenols, tannins, flavonoids, and flavonols, and in vitro antioxidant activity in variants of Laghupanchmula formulations. Qualitative high-performance liquid chromatography (HPLC) analysis has also been performed to establish presence/absence of important chemical constituents in formulations. Results Additional quantity of phenols, tannins, flavonoids, and flavonols has been observed in Laghupanchamula variant containing Eranda than the variant containing Gokshura. Greater antioxidant activity has also been found in formulation containing Eranda. The HPLC analysis revealed the presence of shikimic acid, gallic acid, catechin in both formulations, but rutin has been found only in formulation containing Eranda. Conclusion From the results of experiments it has been observed that the formulation containing Eranda has more antioxidant activity as it contains more quantities of phenol, tannins, flavonoids, and flavonols than the formulation containing Gokshura. How to cite this article Ghildiyal S, Joshi A, Joshi VK. Comparative Study on Two Variants of Laghupanchamula (A Compound Ayurvedic Formulation) for Important Groups of Phytochemicals and Antioxidant Activity. J Drug Res Ayurvedic Sci 2017;2(3):157-163.


Allergy ◽  
2001 ◽  
Vol 56 (7) ◽  
pp. 684-687 ◽  
Author(s):  
M. A. Croce Portocarrero ◽  
E. Rosa da Costa Manso ◽  
W. Gambale ◽  
L. Takayama ◽  
C. E. Oliveira Andrade ◽  
...  

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Ano Wariyo ◽  
Habtamu Gebreselassie ◽  
Wondmagegnehu Gerbatsedik ◽  
Kifle Belachew

Coffee is the most important and second traded commodity next to oil in the world. In Ethiopia, coffee leaf rust caused by Hemileia vastatrix is one of the third most economically important diseases of Coffee Arabica. The current status of coffee leaf rust was intensively assessed and examined in 189 sample coffee farms from six districts across major coffee growing areas of the Southern Ethiopia. At each farm, ten randomly selected trees on a diagonal transect across the farm were assessed for disease incidence and severity. The survey data showed that coffee leaf rust was present in all assessed district varying in magnitude and extent of damage. The highest overall mean of rust incidence (38.6%) and severity (13.80%) was recorded at Dilla zuria while the lowest incidence (10.52%) and severity (1.38%) was at Yergachaffee district. The highest altitude range was obtained at Yergachaffee (1838-2056) while the lowest was at Dilla zuria (1434-1825) district. Overall mean severity and incidence result indicate that, there was statistical (p = 0.058 for severity, p = 0.044 for incidence) and negative correlation between intensity and altitude (severity, r= -0.80 and incidence, r= -0.82). The linear regression equation of severity and incidence obtained from the data was Y= -0.036X+73.16 and Y = -0.074X +158.9 (where Y= percentage CLR severity and incidence, respectively and X= altitude). This regression equation implies that, in higher elevation areas the rust intensity was low as compare to the lower elevation. Finally, the disease was remarkably increasing from time to time in all assessed coffee farms. Therefore, appropriate measurement like farmers’ awareness creation and training on how to control disease as well as appropriate agronomic managements has to be seriously undertaken. In addition, development of coffee leaf rust resistant varieties to southern Ethiopia through resistant breeding has to be set high priority.


Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1763
Author(s):  
Dênia Pires de Almeida ◽  
Eveline Teixeira Caixeta ◽  
Karoliny Ferreira Moreira ◽  
Antonio Carlos Baião de Oliveira ◽  
Kátia Nogueira Pestana de Freitas ◽  
...  

The use of resistant cultivars is the most effective strategy for controlling coffee leaf rust caused by the fungus Hemileia vastatrix. To assist the development of such cultivars, amplified fragment-length polymorphism (AFLP) markers linked to two loci of coffee resistance to races I and II as well as pathotype 001 of H. vastatrix were converted to sequence-characterized amplified region (SCAR) and cleaved amplified polymorphic site (CAPS) markers. In total, 2 SCAR markers and 1 CAPS marker were validated in resistant and susceptible parents as well as in 247 individuals from the F2 population. The efficiency of these markers for marker-assisted selection (MAS) was evaluated in F2:3 and backcross (BCrs2) populations genotyped with the developed markers and phenotyped with race II of H. vastatrix. The markers showed 90% efficiency in MAS. Therefore, the developed markers, together with molecular markers associated with other rust resistance genes, were used for F3:4 and BCrs3 coffee selection. The selected plants were analyzed using two markers associated with coffee berry disease (CBD) resistance, aiming for preventive breeding. MAS of F3:4 and BCrs3 individuals with all resistance loci was feasible. Our phenotypic and genotypic approaches are useful for the development of coffee genotypes with multiple genes conferring resistance to coffee leaf rust and CBD.


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