Cytological Studies on Germinating Teliospores of<i>Hemileia Vastatrix</i>

Chinnappa, C. C.; Sreenivasan, M. S.

doi:10.1080/00087114.1965.10796194

Cited by 9 publications

(10 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Urediniospores are dikaryotic and represent the asexual cycle, re‐infecting the leaves whenever environmental conditions are favourable. Teliospores occur rarely and germinate in situ , producing a promycelium from which four basidiospores are formed (Chinnappa and Sreenivasan, ; Coutinho et al ., ; Fernandes RC et al ., ; Rodrigues et al ., ). Basidiospores cannot infect coffee, but no other host plant has been identified (Kushalappa and Eskes, ; Rodrigues et al ., ).…”

Section: Life Cycle and Infection Processmentioning

confidence: 99%

The coffee leaf rust pathogen Hemileia vastatrix: one and a half centuries around the tropics

Talhinhas

Batista

Diniz

et al. 2017

Molecular Plant Pathology

191

View full text Add to dashboard Cite

Although exhibiting limited genetic polymorphism, the very large genome of H. vastatrix (c. 797 Mbp) conceals great pathological diversity, with more than 50 physiological races. Gene expression studies have revealed a very precocious activation of signalling pathways and production of putative effectors, suggesting that the plant-fungus dialogue starts as early as at the germ tube stage, and have provided clues for the identification of avr genes.

show abstract

Section: Life Cycle and Infection Processmentioning

confidence: 99%

The coffee leaf rust pathogen Hemileia vastatrix: one and a half centuries around the tropics

Talhinhas

Batista

Diniz

et al. 2017

Molecular Plant Pathology

191

View full text Add to dashboard Cite

show abstract

“…Cytological evidence indicates the occurrence of karyogamy and meiosis in asexual spores. However, most researchers ignore the hypothesis of genetic recombination (Chinnappa and Sreenivasan 1965;Rajendren 1967). Genetic abnormalities in the urediniospores were first noted by Rajendren (1967), who described the occurrence of karyogamy and meiosis within these supposed asexual spores based on cytological evidence.…”

Section: Pathogen Biology and Genetic Variabilitymentioning

confidence: 99%

Current status and management of coffee leaf rust in Brazil

Zambolim

2016

Trop. plant pathol.

163

179

View full text Add to dashboard Cite

In Brazil, coffee leaf rust, a fungal disease caused by Hemileia vastatrix Berk. et Br., was first detected in Coffea arabica in January 1970, in the southern region of Bahia state. Today, the disease is present in virtually all arabica and conilon (Coffea canephora) coffee-growing areas of Brazil, and continues to threaten coffee production with losses that range from 30 to 50 %. The disease is usually less severe at elevations above 1,200 m, where the environment is less conducive for the rust. Disease risk is increased in arabica coffee compared to conilon, and lower production is expected in the year following an epidemic due to early defoliation and drying of branches. Several varieties were developed in the country using sources of resistance from germplasm collections in Portugal. However, very few are completely resistant, instead exhibiting various levels of partial resistance. The disease is currently managed through the use of protectant and systemic fungicides including copper, triazoles and strobilurins that should be applied following rules of decision that vary according to the risk scenario. A review of the biology and epidemiology of coffee rust in Brazil is presented and the best management practices for controlling the disease based on advances in breeding for resistance and crop protection are discussed.

show abstract

“…(Asclepiadaceae), in Australia [31] . For both species, this is reflected in abnormal germination and asynchronous nuclear events not only in the true teliospores [18] , [19] , [25] , [27] , but also in the urediniospores on rare occasions [19] , [23] , [32] . It has now been shown that the main coffee species of commerce, Coffea arabica L., is an allotetraploid of recent hybrid origin, with two East African lowland forest species - C. canephora Pierre ex A. Froehner and C. eugenioides S. Moore - as the progenitors [33] .…”

Section: Resultsmentioning

confidence: 99%

“…He termed these “uredinioid teliospores”, but, subsequently, this nuclear process was disputed [18], and it has been ignored since, within the context of coffee rust research. However, a similar nuclear behaviour in the urediniospores of a related rust fungus, Maravalia cryptostegiae (Cummins) Y. Ono, has also been reported more recently [19].…”

Section: Introductionmentioning

confidence: 99%

“…Genetic abnormalities in the urediniospores were first noted by Rajendren [16] , [17] , who described the occurrence of karyogamy and meiosis within these supposed asexual spores, based on cytological evidence. He termed these “uredinioid teliospores”, but, subsequently, this nuclear process was disputed [18] , and it has been ignored since, within the context of coffee rust research. However, a similar nuclear behaviour in the urediniospores of a related rust fungus, Maravalia cryptostegiae (Cummins) Y. Ono, has also been reported more recently [19] .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cryptosexuality and the Genetic Diversity Paradox in Coffee Rust, Hemileia vastatrix

et al. 2011

View full text Add to dashboard Cite

BackgroundDespite 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 ResultsHere, 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.ConclusionsHidden 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.

show abstract

Cytological Studies on Germinating Teliospores ofHemileia Vastatrix

Cited by 9 publications

References 7 publications

The coffee leaf rust pathogen Hemileia vastatrix: one and a half centuries around the tropics

The coffee leaf rust pathogen Hemileia vastatrix: one and a half centuries around the tropics

Current status and management of coffee leaf rust in Brazil

Cryptosexuality and the Genetic Diversity Paradox in Coffee Rust, Hemileia vastatrix

Contact Info

Product

Resources

About