In this study, a survey of physiological races of Hemileia vastatrix was carried out on 34 coffee leaf rust populations collected at several coffee genotypes in Brazil. After the inoculation on leaf disc of coffee differential clones, the races I, II, III, XIII, XVII and XXXVII were characterised. This is the first report of race XXXVII on Coffea arabica in Brazil, which shows the evolutionary potential of H. vastatrix. The emergence of complex races like XXXVII represents a challenge for breeders in the development of resistant cultivars

CABRAL, P G. C.

CAIXETA, E. T.

CAPUCHO, A. S.

LELIS, T. P.

ZAMBOLIM, E. M.

ZAMBOLIM, L.

In this study, a survey of physiological races of Hemileia vastatrix was carried out on 34 coffee leaf rust populations collected at several coffee genotypes in Brazil. After the inoculation on leaf disc of coffee differential clones, the races I, II, III, XIII, XVII and XXXVII were characterised. This is the first report of race XXXVII on Coffea arabica in Brazil, which shows the evolutionary potential of H. vastatrix. The emergence of complex races like XXXVII represents a challenge for breeders in the development of resistant cultivars.Made available in DSpace on 2011-04-09T22:28:02Z (GMT). No. of bitstreams: 1
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Identification of a new race of Hemileia vastratix in Brazil.

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Identiﬁcation of a new race of Hemileia vastatrix in BrazilP. G. C. CabralA, E. M. ZambolimA, L. ZambolimA,C, T. P. LelisA, A. S. CapuchoA and E. T. CaixetaBADepartamento de Fitopatologia, Universidade Federal de Vic¸osa, 36570-000, Vic¸osa, M.G., Brazil.BEmbrapa Café, Parque Estac¸ão Biológica, Av. W3 Norte, 70770-901, Brasília, D.F., Brazil.CCorresponding author. Email: zambolim@ufv.brAbstract. In this study, a survey of physiological races of Hemileia vastatrix was carried out on 34 coffee leaf rustpopulations collected at several coffee genotypes in Brazil. After the inoculation on leaf disc of coffee differential clones, theraces I, II, III, XIII, XVII andXXXVIIwere characterised. This is theﬁrst report of raceXXXVII onCoffea arabica inBrazil,which shows the evolutionary potential ofH. vastatrix. The emergence of complex races likeXXXVII represents a challengefor breeders in the development of resistant cultivars.Coffee leaf rust caused by Hemileia vastatrix Berk. et Br. is themost devastating disease onCoffea arabica in Brazil. The fungusis largely distributed in all the coffee-growing areas of thecountry, causing losses between 10%and 40% (Silva et al. 2006).The development of coffee varieties with durable resistance tocoffee leaf rust has been a challenge due to the great geneticvariability ofH. vastatrix populations. In the pathosystem coffeeversus coffee leaf rust, 45 pathogenic races of H. vastatrix weredescribed in the world (Várzea and Marques 2005). In Brazil,previous studies differentiated 14 races identiﬁed as I, II, III, VII,X, XIII, XV, XVI, XVII, XXI, XXII, XXIII, XXIV, XXV orXXXI. The race II is the most widely distributed in Brazil(Zambolim et al. 2005). Considering that no other studies havebeen carried out in the country since 2002 and the loss ofresistance in some improved commercial coffee varieties, thissurvey aimed to identify the current physiological races ofH. vastatrix occurring in Brazil.This survey analysed 34 populations of H. vastatrix collectedfrom diseased leaves of Coffea arabica, C. canephora andinterspeciﬁc hybrids in the States of Minas Gerais, EspíritoSanto and São Paulo, which represents the main production areaof commercial coffee in Brazil. The urediniospores ofH. vastatrixwere collected from the infected leaves with a gelatin capsule andstored inside glass ampoules sealed with cotton. The ampouleswere maintained inside a desiccator contained a sulfuric acidsolution (density of 1.8 and concentration of 32.6%) to maintainthe relative humidity around 50% at 5C (Zambolim and Chaves1974). Each samplewas inoculated in the susceptible plantsCatuaíVermelho (Coffea arabica) or in the clone 02 ofCoffea canephorain order to obtain the amount of urediniospores necessary forphysiological race differentiation. Only urediniospores with aviability superior to 30% were considered appropriate for theinoculation tests (Capucho et al. 2009). The inoculations in thedifferential cloneswere done according to a leaf discmethodology(Eskes 1982) with modiﬁcations. Urediniospores from each of34 H. vastatrix populations were individually inoculated with acamelhair brush over the abaxial surface of nine leaf discs of eachcoffee differential clone. Each set of inoculated leaf discs perclone was then transferred to a polystyrene box (11 11 3 cm)containing a nylon and foam fabric saturated with water. The leafdiscs were then sprayed with distilled water to maintain themoisture around 100% (Fig. 1). The gerbox containing the leafdiscs were closed and stored in the dark for 48 h at 24C, and thentransferred to a chamber under controlled temperature and lightconditions (22C, 12 h ﬂuorescent light). After this period theinoculated leaf discs were cleaned with sterilised cotton toeliminate non-germinated urediniospores and hyperparasiticcontaminants (Capucho et al. 2009).The characterisation of the physiological races present inthe 34 populations of H. vastatrix was done based on thereadings of the phenotypic expression (absence or presence ofurediniospores) on the inoculated coffee leaf discs of thedifferential clones (Fig. 1). The evaluation started when theﬁrst urediniospores formed on the abaxial surface of the leaveson the susceptible controls (Catuaí Vermelho and clone 02 ofC. canephora). Four evaluations were carried out at 7-dayintervals and the recorded results were compared with the datadescribed in the literature (Várzea and Marques 2005).In the 34 evaluated populations the races I, II, III, XIII, XVIIand XXXVII were identiﬁed (Table 1). Race I was characterisedin ﬁve populations. Race II was predominantly found in 65% ofthe evaluated samples. Race IIIwas identiﬁed in four samples andraces XIII, XVII, XXXVII in one sample each.This is the ﬁrst report of the occurrence of race XXXVII inBrazil. This complex race was identiﬁed in a sample collected atMinas Gerais State in a growing C. arabica Catuaí Vermelhoﬁeld located at 1137m altitude, 1940091 S and 4613058W. Thisﬁnd is of extreme importance due to the potential of this race toinfect all the coffee rust-resistant varieties available to theproducers in Brazil. This race has ﬁve virulence genes in itsgenetic constitution (v2,5,6,7,9) able to infect the differentiators ofﬁve physiologic groups of Coffea: groups D, E, R, 1 and 3.CSIRO PUBLISHINGwww.publish.csiro.au/journals/apdn Australasian Plant Disease Notes, 2009, 4, 129–130 Australasian Plant Pathology Society 2009 10.1071/DN09052 1833-928X/09/010129Therefore, it is of great importance to study how this race isdisseminated and its capability to cause an epidemic in thecountry.AcknowledgementsThe authors acknowledge the Fundac¸ão de Amparo à Pesquisa do Estadode Minas Gerais (FAPEMIG), Consórcio Brasileiro de Pesquisa eDesenvolvimento do Café (CBP&D), Conselho Nacional deDesenvolvimento Cientíﬁco e Tecnológico (CNPq) and Ministério daAgricultura Pecuária e Abastecimento (MAPA) for providing ﬁnancialsupport. P.G.C. Cabral and A.S. Capucho acknowledge the ConselhoNacional de Desenvolvimento Cientíﬁco e Tecnológico – CNPq forproviding the student grant.ReferencesCapucho AS, Caixeta ET, Zambolim EM, Zambolim L (2009) Heranc¸a daresistência do Híbrido de Timor UFV 443–03 à ferrugem-do-cafeeiro.Pesquisa Agropecuaria Brasileira 44, 276–282. doi: 10.1590/S0100-204X2009000300009Eskes AB (1982) The use of leaf disk inoculations in assessing resistanceto coffee leaf rust (Hemileia vastatrix). Netherlands Journal of PlantPathology 88, 127–141. doi: 10.1007/BF01977270Silva MDC, Várzea VMP, Guimarães LG, Azinheira HG, Fernandez D,Petitot AS, Bertrand B, Lashermes P, Nicole M (2006) Coffee resistanceto the main diseases: leaf rust and coffee berry disease. BrazilianJournal of Plant Physiology 18, 119–147. doi: 10.1590/S1677-04202006000100010Várzea VMP, Marques DV (2005) Population variability of Hemileiavastatrix vs. coffee durable resistance. In, ‘Durable Resistance toCoffee Leaf Rust’ (Eds L Zambolim, EM Zambolim, VMP Várzea).pp. 53–74. (Vicosa: Universidade Federal de Vic¸osa).Zambolim L, Chaves GM (1974) Efeito de baixas temperaturas e do binômiotemperatura-umidade relativa sobre a viabilidade dos uredosporosde Hemileia vastatrix Berk. et Br. e Uromyces phaseolityca Arth.Experientiae 17, 151–184.Zambolim L, Zambolim EM, Várzea VMP (2005) Durable resistance tocoffee leaf rust. (Vic¸osa: UFV; Oeiras: CIFC) 450 pp.Manuscript received 12 November 2009, accepted 23 November 2009(A) (B) (C)Fig. 1. Scheme showing the inoculationofHemileia vastatrixusing the leaf discmethod. (A) spreadof urediniospores in the leaf discwith the help of a camelhairbrush; (B) abaxial water-spraying of the leaf discs after inoculation; (C) urediniospores on abaxial epidermis of the susceptible cv. Catuaí.Table 1. Physiological races of Hemileia vastatrix identiﬁed by coffeedifferential clonesNumber of isolatesevaluatedGenes of thepathogenRaceidentiﬁed5 v 2,5 I22 v 5 II4 v 1,5 III1 v 5,? XIII1 v 1,2,5 XVII1 v 2,5,6,7,9 XXXVII130 Australasian Plant Disease Notes P. G. C. Cabral et al.http://www.publish.csiro.au/journals/apdn

Identification of a new race of Hemileia vastatrix in Brazil.

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Identification of a new race of Hemileia vastratix in Brazil.

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Repository Open Access to Scientific Information from Embrapa