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In Vitro and In Vivo Tests for Parasitism of Verticillium psalliotae Treschow on Hemileia Vastatrix BERK. and BR.
Mahfud, M. C.,Mior Ahmad, Z. A.,Meon, S.,Kadir, J.
Malaysian Journal of Microbiology , 2006,
Abstract: The fungus Verticillium psalliotae Treschow is known to grow on the rust sori masses of Hemileia vastatrix in coffee plantings in Malaysia. However, published reports on this parasite or other biocontrol organisms present naturally in the coffee ecosystems in Malaysia are lacking. In vitro and in vivo studies were conducted to elucidate evidence of parasitism of V. psalliotae on H. vastatrix. The host-mycoparasite interaction conducted in vitro resulted a significant reduction in germination of Hemileia uredespores and an increase in germination of Verticillium conidia. A significant reduction in leaf rust severity by the presence of V. psalliotae, particularly when V. psalliotae was applied 24 hours before the inoculation of H. vastatrix, demonstrated an evidence parasitism in vivo. The evidences were supported by SEM observation of penetration and damage to Hemileia uredospores by hyphae of V. psalliotae.
SELECCIóN in vitro DE AISLAMIENTOS PROMISORIOS DE Lecanicillium lecanii (ZARE Y GAMS) PARA LA LUCHA BIOLóGICA DE Hemileia vastatrix (BERK. et Br.)
González,E; Moraima,Surís;
Revista de Protecci?3n Vegetal , 2007,
Abstract: the heuristic method determining the weight of the biological and physiological values of each isolate was used to select promissory strains of lecanicillium lecanii (zare and gams) as biological control agents. the target pest was hemileia vastatrix (berk. et br.) causal agent of coffee rust. this novel method in this type of study permitted the selection of v1-01 as the isolate with the best attributes according to its mycelium growth on different culture media at the temperature and relative humidity values studied, better sporulation on solid media, higher percentages of parasitism and deformation of the phytopathogen uredospores resulting successful as a tool of analysis for selection.
Produtividade e resistência à ferrugem do cafeeiro (Hemileia vastatrix BERK. ET BR.) de progênies F5 de catuí amarelo com o híbrido de timor
Miranda, José Messias;Perecin, Dilermando;Pereira, Antonio Alves;
Ciência e Agrotecnologia , 2005, DOI: 10.1590/S1413-70542005000600013
Abstract: eighteen progenies in the f5 generation of the h 419 hybrid were studied, proceeding from the crossing between the híbrido detimor (ufv 445-46) and the iac 30 catuaí amarelo (ufv 2143), 5 progenies in the f5 generation of the h 516 hybrid, proceeding from the crossing between the híbrido detimor (ufv 446-08) and the iac 86 catuaí amarelo (ufv 2154) and the iac 44 the red catuaí (ufv 2144) as control, with and without rust control. regarding the production of cherry coffee by plant and with the rust attack, the h419-3-1-1-14 and the h516-2-1-1-18, progenies were the ones that showed greater productivity and rust resistance (grade 0), followed by the h419-6-3-6-12, but with partial rust resistance . these progenies were, also, the ones that showed greater length of the plagiotrophycal spreads, where influenciated in 37.73% (r2) at production of cherry coffee by plant. the plagiotrophycal spread's length, fust diameter and plants height were the most correlated attributes r = 0.5977, r = 0.3316 and r = 0.2848, p < 0.01 respectively, with these progenies productivity, according results obtained by dhaliwal (1968). regarding to the hemileia vastatrix berk. et br. fungus resistance, the progenies showed herdability on the wide-high way (ha2 = 0,80 between and ha2 = 0,96 between and inside the progenies), pointing them as resistant and with a high genetic variability for selection of resistant material to the coffee rust.
Avalia??o e sele??o de progênies F3 de cafeeiros de porte baixo com o gene SH3 de resistência a Hemileia vastatrix Berk. et Br.
Concei??o, Albano Silva da;Fazuoli, Luiz Carlos;Braghini, Masako Toma;
Bragantia , 2005, DOI: 10.1590/S0006-87052005000400004
Abstract: the present work evaluated 36 arabic coffee (coffea arabica l.) f3 progenies, originated from crosses among cultivars catuaí vermelho iac 46 and catuaí vermelho iac 81 and access iac 1110 (ba-10). this last cultivar came from india and exhibits sh2 and sh3 rust resistance genes. the experiment was installed in 1988 at the experimental center of the agronomic institute (iac/apta), in campinas, using random blocks design with six repetitions and two plants per plot. field evaluations included yield (average of seven annual harvests), vegetative vigor, resistance to leaf rust, plant size, color of young leaves and complete fruit maturation period. based on these evaluations, plants exhibiting high yield, good vegetative vigor, low height, and resistance to the leaf rust agent hemileia vastatrix were selected. fruit yield of selected plants was calculated and seeds were characterized according to type (flat, peaberry and elephant), outturn and grain size. a total of 11 optimal f3 progenies were identified as rust resistant. by further classifications, 39 plants out from these progenies were selected, along with 15 plants from other 25 evaluated progenies. laboratory analyses lead to a final selection of 18 coffee trees, all exhibiting leaf rust resistance, high yield and low height. also, f4 progenies of selected plants had been evaluated regarding height and leaf rust resistance, at seedling stage, in greenhouse conditions. eighteen plants were selected for further analysis and move forward from f3 to f4 generation in the coffee breeding program developed by iac.
Cryptosexuality and the Genetic Diversity Paradox in Coffee Rust, Hemileia vastatrix  [PDF]
Carlos Roberto Carvalho, Ronaldo C. Fernandes, Guilherme Mendes Almeida Carvalho, Robert W. Barreto, Harry C. Evans
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026387
Abstract: Background Despite the fact that coffee rust was first investigated scientifically more than a century ago, and that the disease is one of the major constraints to coffee production - constantly changing the socio-economic and historical landscape of the crop - critical aspects of the life cycle of the pathogen, Hemileia vastatrix, remain unclear. The asexual urediniospores are regarded as the only functional propagule: theoretically, making H. vastatrix a clonal species. However, the well-documented emergence of new rust pathotypes and the breakdown in genetic resistance of coffee cultivars, present a paradox. Methods and Results Here, using computer-assisted DNA image cytometry, following a modified nuclear stoichiometric staining technique with Feulgen, we show that meiosis occurs within the urediniospores. Stages of spore development were categorised based on morphology, from the spore-mother cell through to the germinating spore, and the relative nuclear DNA content was quantified statistically at each stage. Conclusions Hidden sexual reproduction disguised within the asexual spore (cryptosexuality) could explain why new physiological races have arisen so often and so quickly in Hemileia vastatrix. This could have considerable implications for coffee breeding strategies and may be a common event in rust fungi, especially in related genera occupying the same basal phylogenetic lineages.
Confirmation of the occurrence of teliospores of Hemileia vastatrix in Brazil with observations on their mode of germination
Fernandes, Ronaldo de Castro;Evans, Harry Charles;Barreto, Robert W.;
Tropical Plant Pathology , 2009, DOI: 10.1590/S1982-56762009000200005
Abstract: the occurrence of teliospores of hemileia vastatrix in brazilis confirmed for the first time and clearly documented under light microscopy and sem. additionally, voucher specimens of leaves containing sori with germinated and non-germinated teliospores were deposited in a local herbarium (herbário vic). the previous publication claiming to provide an account of the occurrence of teliospores of h. vastatrix in brazil did not include appropriate images or an indication of voucher specimens. observations during 2006, at a site in the zona da mata coffee-growing region of minas gerais, brazil, revealed the presence of teliospores during the winter months (july-september), probably triggered by the fall in temperature and decreasing rainfall immediately prior to and during this period. a significant proportion of these teliospores exhibited abnormal germination: the number of promycelial cells varying from three to seven, with or without the production of sterigmata. basidiospores were variable in size and shape, possibly indicating genetic instability, and this is discussed in relation to the life-cycle of coffee leaf rust.
Additional physiological races of coffee leaf rust (Hemileia vastatrix) identified in Kenya
Elijah K. Gichuru,John M. Ithiru,Maria C. Silva,Ana P. Pereira
Tropical Plant Pathology , 2012, DOI: 10.1590/s1982-56762012000600008
Abstract: Coffee leaf rust (CLR), caused by the fungus Hemileia vastatrix, is among the most important diseases affecting coffee all over the world. In Kenya, it is currently the second most important disease, and breeding coffee to obtain new resistant cultivars has been a priority. Over time, new rust pathogenic races able to infect hitherto resistant coffee genotypes have been registered. To date, 49 races of the pathogen have been characterized all over the world. The most recent races to be characterized are able to infect derivatives of Timor Hybrid (HDT), which is a major source of resistance in breeding programs. This work aimed to identify new races of the pathogen in Kenya, emphasizing infected leaves sampled from CLR resistant varieties and breeding lines collected from two sites (Ruiru and Koru). Twenty-four samples were characterized, out of which 22 samples corresponded to new races of the pathogen. A total of six new races (III, XVII, XXIII, XXXVI, XLI and XLII) were characterized, revealing three new virulence genes (v1, v7, v8) and possibly a fourth virulence gene, the v9. This finding represents a serious threat to coffee production and also a challenge to coffee breeding programs that are in progress in Kenya.
Estudos preliminares sobre as invertases de cafeeiros atacados por Hemileia vastatrix
Carvalho, Paulo de Campos Torres de;
Anais da Escola Superior de Agricultura Luiz de Queiroz , 1972, DOI: 10.1590/S0071-12761972000100015
Abstract: the present research, considered exploratory by the author, was dons in order to study leaf invertases of two coffee varieties, geisha (sh1sh5) and kent sh2sh5) inoculated with races iii (v1v5) and xxiv (v2v4) of hemileia vastatrix. the geisha coffee is susceptible to race iii and resistant to race xxiv, while kent coffee has opposite reactions. in each pair of leaves, one was inoculated and the other was kept as control. determinations of the invertases were made at 6 and 16 days after inoculation. the preliminary results showed that in the susceptible combinations there was no changes in the invertases, that were the same as in the healthy plants, with the maximum of activity at ph 4.5. in the resistant combinations, however, it was found an "acid invertase ph 4.0" on the 6th day after inoculations. this invertase was absent in both healthy and infected plants of the same varieties. the occurrence on the "acid invertase ph 4.0" is related to the decrease in the sucrose content of the leaves. the author suggest three hipothesis that could explain a relation of this "acid invertase ph 4.0" with the coffee rust pathogenesis. these hipothesis, which could occur alone or simultaneously are: 1) the sucrose would be deviated to the formation of defense substances, such as phenols, phytoalexins and others. 2) the sucrose would be deviated to others parts of the plant, in 2l physiological process similar to that of the leaves in senescence. 3) there would be an increase in the respiration and metabolism of the infected tissues, with the implicit consumption of the stored energy.
Efeito de alta temperatura no desenvolvimento de Hemileia vastatrix em cafeeiro suscetível
Ribeiro, Ivan José Antunes;Monaco, Lourival Carmo;Tisseli Filho, Otávio;Sugimori, Mauro Hideo;
Bragantia , 1978, DOI: 10.1590/S0006-87051978000100002
Abstract: the development of rust epidemics in tropical conditions of brazil has been different than previously expected. despite of high humidity the development is reduced to a minimum during the summer. high temperature was assumed to have a detrimental effect on the rust development. this paper reports the results of a study concerning the effect of high temperature on hemileia vastatrix development. temperature treatment of inoculated young plants at 400c for 4 hours in 4 consecutive days was sufficient to prevent rust development. the curative effect was permanent indicating that the fungus was destroyed inside the plant tissue. practical implications of such results are considered.
Chlorogenic acid levels in leaves of coffee plants supplied with silicon and infected by Hemileia vastatrix
Rodrigues, Fabrício A.;Carré-Missio, Vivian;Jham, Gulab N.;Berhow, Mark;Schurt, Daniel A.;
Tropical Plant Pathology , 2011, DOI: 10.1590/S1982-56762011000600010
Abstract: rust, caused by hemileia vastatrix, is the main disease that decreases coffee production in brazil. new and enhanced methods to reduce rust intensity that can be integrated with modern genetic and chemical approaches need to be investigated. considering that many plant species supplied with silicon (si) show increased resistance to several pathogens, this study examined the possible effect of this element in increasing chlorogenic acid (ca) concentrations in coffee leaves and, consequently, increasing the level of resistance to rust. plants (cv. "catuaí vermelho iac 44") were inoculated with h. vastatrix after growing for 35 days in a hydroponic culture amended with 0 (-si) or 2 (+si) mm si. concentration of si in leaf tissues was of 0.36 and 0.42 dag/kg for -si and +si treatments, respectively, but without a statistically significant difference. the area under rust progress curve was 154.5 and 119.4 for -si and +si treatments, respectively, but without significant statistical difference. for non-inoculated plants, the concentrations of total ca and caffeoyl-quinic acid (cqa)compounds (dicqa) were similar between -si and +si treatments. even though there was an increase of 236.4 and 257.1%, respectively, for total ca and dicqa for +si when compared to -si treatment at 30 days after inoculation with h. vastatrix, reduction on rust severity was not obtained once the fungus had already colonized the leaf tissues. therefore, regardless of the increase in the concentrations of chlorogenic acid on leaves, coffee resistance to h. vastatrix infection was not potentialized by si.
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