Development of infection structures by Hemileia vastatrix in resistant and susceptible selections of Coffea and in Phaseolus vulgaris

1993 ◽  
Vol 71 (8) ◽  
pp. 1001-1008 ◽  
Author(s):  
T. A. Coutinho ◽  
F. H. J. Rijkenberg ◽  
M. A. J. van Asch
Keyword(s):  
Phaseolus Vulgaris ◽  
Primary Infection ◽  
Intercellular Spaces ◽  
Hemileia Vastatrix ◽  
Mesophyll Cells ◽  
Sequence Of Events ◽  
Successful Infection ◽  
Coffee Leaf Rust ◽  
Subsidiary Cells ◽  
Mother Cells

The sequence of events leading to successful infection of Coffea by Hemileia vastatrix, following the formation of an appressorium over a stoma, was investigated using scanning electron microscopy. In the host, Coffea arabica, a torpedoshaped substomatal vesicle initial develops bilaterally from the apex of the infection wedge, while in the nonhost, Phaseolus vulgaris, the infection wedge protrudes into the substomatal chamber. The substomatal vesicle in both host and nonhost, at 48 h postinoculation, is anchor shaped. Haustorial mother cells are formed on stubby primary infection hyphae that curve back onto subsidiary cells. No differences in appearance of these structures were noted between resistant and susceptible coffee selections. A much-branched mycelium ramifies through the intercellular spaces of the mesophyll cells 96 h postinoculation in the host. In bean, the SSV began to collapse 48 h postinoculation. Key words: coffee leaf rust, infection, penetration, Coffea, appressorium, substomatal vesicle.

Non-host resistance responses of Arabidopsis thaliana to the coffee leaf rust fungus (Hemileia vastatrix)

Botany ◽  
2010 ◽  
Vol 88 (7) ◽  
pp. 621-629 ◽  
Author(s):  
Helena Gil Azinheira ◽  
Maria do Céu Silva ◽  
Pedro Talhinhas ◽  
Clara Medeira ◽  
Isabel Maia ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Leaf Rust ◽  
Rust Fungus ◽  
Hemileia Vastatrix ◽  
Callose Deposition ◽  
Mesophyll Cells ◽  
Model Plant ◽  
Heterologous System ◽  
Coffee Leaf Rust ◽  
Model Plant Arabidopsis Thaliana

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.

Presymptomatic multiplication of Xanthomonas campestris pv. vesicatoria on the surface of pepper leaves

1982 ◽  
Vol 60 (7) ◽  
pp. 1041-1045 ◽  
Author(s):  
Edna Sharon ◽  
Yoav Bashan ◽  
Yaacov Okon ◽  
Yigal Henis
Keyword(s):  
Primary Infection ◽  
Xanthomonas Campestris ◽  
Leaf Surface ◽  
Necrotic Tissue ◽  
Intercellular Spaces ◽  
Mesophyll Cells ◽  
Pepper Leaves ◽  
Electron And Light Microscopy ◽  
Xanthomonas Vesicatoria ◽  
Scanning Electron

Xanthomonas vesicatoria infection of pepper leaves was monitored by scanning electron and light microscopy. During incubation the bacteria became located in the intercellular spaces between the mesophyll cells. The primary infection sites were the vein areas. Xanthomonas vesicatoria reach high population levels on the leaf surface but usually not in the stomata. Necrosis was first observed microscopically 120 h after inoculation near the leaf veins. Bacteria were detected in infected tissue but not in necrotic tissue.

scholarly journals New species and records of Trichoderma isolated as mycoparasites and endophytes from cultivated and wild coffee in Africa

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María del Carmen H. Rodríguez ◽  
Harry C. Evans ◽  
Lucas M. de Abreu ◽  
Davi M. de Macedo ◽  
Miraine K. Ndacnou ◽  
...  
Keyword(s):  
New Species ◽  
Cloud Forest ◽  
Elongation Factor ◽  
Classical Biological Control ◽  
Hemileia Vastatrix ◽  
Translation Elongation ◽  
Coffee Leaf Rust ◽  
Novel Taxa ◽  
Coffee Plants ◽  
Wild Coffee

AbstractA survey for species of the genus Trichoderma occurring as endophytes of Coffea, and as mycoparasites of coffee rusts (Hemileia), was undertaken in Africa; concentrating on Cameroon and Ethiopia. Ninety-four isolates of Trichoderma were obtained during this study: 76 as endophytes of healthy leaves, stems and berries and, 18 directly from colonized rust pustules. A phylogenetic analysis of all isolates used a combination of three genes: translation elongation factor-1α (tef1), rpb2 and cal for selected isolates. GCPSR criteria were used for the recognition of species; supported by morphological and cultural characters. The results reveal a previously unrecorded diversity of Trichoderma species endophytic in both wild and cultivated Coffea, and mycoparasitic on Hemileia rusts. Sixteen species were delimited, including four novel taxa which are described herein: T. botryosum, T. caeruloviride, T. lentissimum and T. pseudopyramidale. Two of these new species, T. botryosum and T. pseudopyramidale, constituted over 60% of the total isolations, predominantly from wild C. arabica in Ethiopian cloud forest. In sharp contrast, not a single isolate of Trichoderma was obtained using the same isolation protocol during a survey of coffee in four Brazilian states, suggesting the existence of a ‘Trichoderma void’ in the endophyte mycobiota of coffee outside of Africa. The potential use of these African Trichoderma isolates in classical biological control, either as endophytic bodyguards—to protect coffee plants from Hemileia vastatrix, the fungus causing coffee leaf rust (CLR)—or to reduce its impact through mycoparasitism, is discussed, with reference to the on-going CLR crisis in Central America.

scholarly journals Comparative Study on Gas Exchange, Water Relations and Leaf Anatomy of Two Olive Cultivars Grown under Well-Irrigated and Drought Conditions

1999 ◽  
Vol 54 (9-10) ◽  
pp. 688-692 ◽  
Author(s):  
Konstantinos Chartzoulakis ◽  
Angelos Patakas ◽  
Artemis Bosabalidis
Keyword(s):  
Gas Exchange ◽  
Water Relations ◽  
Volume Fraction ◽  
Spongy Parenchyma ◽  
Intercellular Spaces ◽  
Palisade Parenchyma ◽  
Mesophyll Cells ◽  
Olive Cultivars ◽  
Olea Europea ◽  
Leaf Anatomical Characteristics

The effect of water stress on gas exchange, water relations and leaf anatomical characteristics have been studied in two olive cultivars (Olea europea, L. cv. ‘Koroneiki’ and cv. ‚Mastoidis’). Photosynthetic rate as well as stomatal conductance were decreased in stressed plants. Osmotic potential (π) declined rapidly in stressed plants indicating their ability for osmoregulation. Bulk modulus of elasticity (ε) was significantly higher in stressed compared to well irrigated plants. The volume fraction of intercellular spaces of the upper palisade parenchyma, the spongy parenchyma as well as the lower palisade parenchyma were significantly lower in stressed compared to well irrigated plants. On the other hand, the density of mesophyll cells in the upper palisade parenchyma, spongy parenchyma and lower palisade parenchyma increased significantly in stressed plants

scholarly journals A fungus-eat-fungus world: Digitopodium, with particular reference to mycoparasites of the coffee leaf rust, Hemileia vastatrix

IMA Fungus ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Adans A. Colmán ◽  
Harry C. Evans ◽  
Sara S. Salcedo-Sarmiento ◽  
Uwe Braun ◽  
Kifle Belachew-Bekele ◽  
...  
Keyword(s):  
Leaf Rust ◽  
Democratic Republic Of Congo ◽  
Sequence Data ◽  
Molecular Study ◽  
Classical Biological Control ◽  
Coffea Canephora ◽  
Molecular Data ◽  
Phylogenetic Position ◽  
Hemileia Vastatrix ◽  
Coffee Leaf Rust

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.

scholarly journals PERKECAMBAHAN UREDOSPORA HEMILEIA VASTATRIX PADA EKSTRAK RIMPANG JAHE DAN KUNYIT SERTA DAUN CENGKEH DAN SIRIH

2006 ◽  
Vol 6 (1) ◽  
pp. 52-58
Author(s):  
Cipta Ginting
Keyword(s):  
Block Design ◽  
Water Extract ◽  
Piper Betle ◽  
Distilled Water ◽  
Control Methods ◽  
Hemileia Vastatrix ◽  
Coffee Leaf Rust ◽  
Randomized Complete Block Design ◽  
Test Treatments ◽  
Germ Tubes

Germination of Hemileia vastatrix uredospores on crude water extracts of zinger and turmeric rhizome and clove and Piper betle leaves.  Coffee leaf rust caused by H. vastatrix especially on Arabica coffee is one of most important diseases in coffee and conventional control methods of leaf coffee rust is still unsatisfactory.  The objective of this study was to determine the effect of crude water extract on the germination of H. vastatrix uredospores.  The study was conducted from January to September 2004 in the Laboratory of Plant Pathology at Unila.  In each test, treatments were arranged in a randomized complete block design with four replications.  Crude water extract was prepared by homogenizing 100 g of material in 100 ml sterilized distilled water.  After being passed through four layers of sterilized cheesecloth, the mixture was defined as the aliquot (100% extract) and dilutions were made with sterile distilled water to obtain concentrations of 2.5 to 10%.  Each of four materials (zinger, turmeric, clove, and Piper betle) was tested separately in five aliquot concentration levels.  One ml of each extract was mixed with 0.25 ml of uredospora suspension (4 x 105 per ml), and 0.2 ml of the mixture was incubated.  The variable was germinated uredospora (%) that was determined under a mikroscope.  The results show that significant reduction in spore germination occurred by  turmeric, clove, and P. betle extracts at > 2.5% and by zinger extract at > 5%.  Some uredospora exposed to plant extract germinated abnormally:  germ tubes shorten, swollen, or malform.

scholarly journals Stability of Arabica coffee genotype (Coffea arabica L.) against leaf rust (Hemileia vastatrix)

2021 ◽  
Vol 748 (1) ◽  
pp. 012002
Author(s):  
Sabam Malau ◽  
Albiner Siagian ◽  
Maria Rumondang Sihotang
Keyword(s):  
Leaf Rust ◽  
Block Design ◽  
Research Result ◽  
Dry Season ◽  
Environment Interaction ◽  
Rust Disease ◽  
Hemileia Vastatrix ◽  
Arabica Coffee ◽  
Coffee Leaf Rust ◽  
Rust Severity

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.

Cytological responses induced by five phytopathogenic fungi in a nonhost plant, Phaseolus vulgaris

1986 ◽  
Vol 64 (3) ◽  
pp. 648-657 ◽  
Author(s):  
Myriam R. Fernandez ◽  
Michèle C. Heath
Keyword(s):  
Phenolic Compounds ◽  
Phaseolus Vulgaris ◽  
Fungal Growth ◽  
Phytopathogenic Fungi ◽  
French Bean ◽  
Mesophyll Cells ◽  
Fresh Tissue ◽  
Susceptible Host ◽  
Nonhost Plant ◽  
Blue Reaction

Responses of the French bean plant (Phaseolus vulgaris L. cv. Pinto) to the nonpathogenic fungi Helminthosporium maydis Nisikado and Miyake (perfect stage Cochliobolus heterostrophus (Drechsler) Drechsler), Stemphylium sarcinaeforme (Cav.) Wiltish., S. botryosum Wallr., Cladosporium fulvum Cooke, and Uromyces vignae Barcl. were examined by cytological and histochemical techniques. All fungi penetrated bean leaves through stomata, and elicited similar modifications in guard and mesophyll cells. Responses involving cell contents were collapse, browning, autofluorescence, and a toluidine blue reaction indicative of the presence of phenolic compounds. Responses associated with cell walls were yellowing, autofluorescence, staining for phenolic compounds, and deposition of callose and of noncallosic, refractive material. In some of the interactions, decolorization and clearing of the tissue for light microscopy induced changes in the frequencies of autofluorescence of cell contents and walls when compared with those observed in fresh tissue. Despite the general similarity of responses elicited by each fungus, striking variations were found among fungi in the percentage of infection sites showing a particular response. For some responses, this variation seemed to be related to the type of interaction each of the fungi has with its susceptible host. It is suggested that even in nonhost plants, the nature and activities of the fungus determine the frequency and extent of the plant's responses. Also, it seems unlikely that all of these responses are involved in the cessation of fungal growth.

Evaluation of Different Botanicals for the Control of Coffee Leaf Rust (Hemileia vastatrix Berkeley and Broome)

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