Increased papilla formation, a major factor of induced resistance in the barley – Erysiphe graminis f.sp. hordei system

1986 ◽  
Vol 64 (10) ◽  
pp. 2178-2181 ◽  
Author(s):  
N. Sahashi ◽  
J. Shishiyama
Keyword(s):  
Leaf Surface ◽  
Specific Resistance ◽  
Hyphal Growth ◽  
Cellular Responses ◽  
Erysiphe Graminis ◽  
Powdery Mildew Fungus ◽  
Challenge Inoculation ◽  
Barley Cultivars ◽  
Abaxial Leaf Surface ◽  
Papilla Formation

Using two barley cultivars, 'Hanna' and 'Russian No. 12', resistance to Erysiphe graminis DC. f.sp. hordei Em. Marchal induced by preliminary inoculation with a compatible or an incompatible race of the powdery mildew fungus was examined with respect to cellular responses. When the primary leaves of barley seedlings were preliminarily inoculated with a compatible or an incompatible race on the abaxial leaf surface, they became resistant to the disease caused by challenge inoculation with the same pathogen on the adaxial surface. The resistance induced was expressed as decrease of fungal penetration and restriction of hyphal growth. These phenomena seemed to be attributable to the increase of papillae or papillalike structures which do not seem to be responsible for the race-specific resistance. On the basis of these results, it is suggested that the resistance induced may be different from race-specific resistance.

The role of the abaxial leaf surface waxes of Lolium spp. in resistance to Erysiphe graminis

1990 ◽  
Vol 39 (4) ◽  
pp. 573-583 ◽  
Author(s):  
T. L. W. CARVER ◽  
B. J. THOMAS ◽  
S. M. INGERSON-MORRIS ◽  
H.W. RODERICK
Keyword(s):  
Leaf Surface ◽  
Erysiphe Graminis ◽  
Abaxial Leaf Surface ◽  
Surface Waxes

scholarly journals Pathogenicity of a Novel Biotype of Limonomyces roseipellis in Tall Fescue

Plant Disease ◽  
2003 ◽  
Vol 87 (9) ◽  
pp. 1031-1036 ◽  
Author(s):  
L. L. Burpee ◽  
C. W. Mims ◽  
L. P. Tredway ◽  
J. Bae ◽  
G. Jung
Keyword(s):  
Dna Sequences ◽  
Tall Fescue ◽  
Leaf Surface ◽  
Controlled Environment ◽  
Binucleate Cells ◽  
Foliar Blight ◽  
Abaxial Leaf Surface ◽  
Leaf Surfaces ◽  
Leaf Tissues ◽  
Papilla Formation

An unusual and undescribed foliar blight of tall fescue was observed in a home lawn and in turf grass research plots near Griffin, GA in May and June, 2000 and 2001. Isolation from lesions yielded mycelium of a basidiomycete with hyphal characteristics (binucleate cells, absence of clamp connections) associated with Laetisaria and Limonomyces spp. Isolates from blighted tall fescue and an isolate of Limonomyces roseipellis formed a clade distinct from isolates of Laetisaria fuciformis based on ribosomal DNA sequences. These data, in conjunction with cultural morphology, indicate that the basidiomycete from tall fescue represents a biotype of Limonomyces roseipellis that lacks clamp connections. In a controlled environment, isolates of the biotype induced foliar blight in the fescue cvs. Kentucky 31 and Rebel III. Histological observations revealed that the fungus colonized leaf surfaces as branched hyphae and aggregated hyphal strands. Penetration occurred via stomatal pores on the abaxial leaf surface. Colonization of leaf tissues was inter- and intracellular, with no evidence of papilla formation in response to invading hyphae. The name “cream leaf blight” is proposed for this new disease of tall fescue.

Picking sides: feeding on the abaxial leaf surface is costly for caterpillars

Planta ◽  
2021 ◽  
Vol 253 (4) ◽  
Author(s):  
Sakshi Watts ◽  
Rupesh Kariyat
Keyword(s):  
Leaf Surface ◽  
Abaxial Leaf Surface

scholarly journals Identification of Race-Specific Resistance in North American Vitis spp. Limiting Erysiphe necator Hyphal Growth

2012 ◽  
Vol 102 (1) ◽  
pp. 83-93 ◽  
Author(s):  
David W. Ramming ◽  
Franka Gabler ◽  
Joseph L. Smilanick ◽  
Dennis A. Margosan ◽  
Molly Cadle-Davidson ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Resistance Genes ◽  
Specific Resistance ◽  
Hyphal Growth ◽  
Resistance Mechanisms ◽  
Hybrid Breeding ◽  
Erysiphe Necator ◽  
Vitis Rotundifolia ◽  
Resistance Sources

Race-specific resistance against powdery mildews is well documented in small grains but, in other crops such as grapevine, controlled analysis of host–pathogen interactions on resistant plants is uncommon. In the current study, we attempted to confirm powdery mildew resistance phenotypes through vineyard, greenhouse, and in vitro inoculations for test cross-mapping populations for two resistance sources: (i) a complex hybrid breeding line, ‘Bloodworth 81-107-11', of at least Vitis rotundifolia, V. vinifera, V. berlandieri, V. rupestris, V. labrusca, and V. aestivalis background; and (ii) Vitis hybrid ‘Tamiami’ of V. aestivalis and V. vinifera origin. Statistical analysis of vineyard resistance data suggested the segregation of two and three race-specific resistance genes from the two sources, respectively. However, in each population, some resistant progeny were susceptible in greenhouse or in vitro screens, which suggested the presence of Erysiphe necator isolates virulent on progeny segregating for one or more resistance genes. Controlled inoculation of resistant and susceptible progeny with a diverse set of E. necator isolates clearly demonstrated the presence of fungal races differentially interacting with race-specific resistance genes, providing proof of race specificity in the grape powdery mildew pathosystem. Consistent with known race-specific resistance mechanisms, both resistance sources were characterized by programmed cell death of host epidermal cells under appressoria, which arrested or slowed hyphal growth; this response was also accompanied by collapse of conidia, germ tubes, appressoria, and secondary hyphae. The observation of prevalent isolates virulent on progeny with multiple race-specific resistance genes before resistance gene deployment has implications for grape breeding strategies. We suggest that grape breeders should characterize the mechanisms of resistance and pyramid multiple resistance genes with different mechanisms for improved durability.

Cryptic speciation in the herbaceous bamboo genus Piresia (Poaceae, Olyreae)

2019 ◽  
Author(s):  
Maria L Silveira de Carvalho ◽  
Izabela S D de Jesus ◽  
Rilquer M da Silva ◽  
Kelly R B Leite ◽  
Alessandra S Schnadelbach ◽  
...  
Keyword(s):  
New Species ◽  
Atlantic Forest ◽  
Leaf Surface ◽  
Conservation Status ◽  
Integrative Approach ◽  
Niche Modelling ◽  
The North ◽  
Abaxial Leaf Surface ◽  
Herbaceous Bamboos ◽  
North Eastern

Abstract Piresia, a small genus of herbaceous bamboos, has a geographical disjunction between the Caribbean and northern/western South America and the north-eastern Atlantic Forest in Brazil. Piresia leptophylla is reported from western Amazonia (WA) and the north-eastern Atlantic Forest (NAF), but its occurrence in western Amazonia is questionable. Using an integrative approach, we combined traditional morphological analysis, anatomy and niche modelling. The results revealed few macromorphological differences between WA and NAF specimens (only plant height, leaf length, lodicule dimensions, shape and position), contrasting with consistent differences in leaf anatomy (macrohairs and cruciform silica bodies in the costal zone of the adaxial/abaxial leaf surfaces, crenate silica bodies on the abaxial leaf surface, lack of panicoid hairs on the abaxial leaf surface, bicellular microhairs and lobed papillae over the abaxial leaf surface, and sparse but elongated fusoid cells in the mesophyll of WA specimens) and in niche patterns. The anatomical/micromorphological characters suggest environmental adaptations to the Amazonian and ‘restinga’ forests, respectively. We therefore propose the segregation of the WA populations into a new species, Piresia tenella sp. nov. We provide a formal description, photographs, a line illustration, a distribution map and discussion of the conservation status for the new species.

scholarly journals Adjuvant Effects on Imazethapyr, 2,4-D and Picloram Absorption by Leafy Spurge (Euphorbia esula)

Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 469-475 ◽  
Author(s):  
W. Mack Thompson ◽  
Scott J. Nissen ◽  
Robert A. Masters
Keyword(s):  
Ammonium Nitrate ◽  
Ammonium Sulfate ◽  
Seed Oil ◽  
Leaf Surface ◽  
Leafy Spurge ◽  
Cuticular Waxes ◽  
Adaxial Leaf Surface ◽  
Abaxial Leaf Surface ◽  
Urea Ammonium Nitrate ◽  
Adjuvant Effects

Laboratory experiments were conducted to identify adjuvants that improve absorption of imazethapyr, 2,4-D amine, and picloram by leafy spurge. Adjuvants (0.25% v/v) included crop oil concentrate (COC), methylated seed oil (MSO), nonionic surfactant (NIS), organosilicones (Silwet L-77®, Sylgard® 309, Silwet® 408), 3:1 mixtures of acetylinic diol ethoxylates (ADE40, ADE65, ADE85) with Silwet L-77, ammonium sulfate (2.5 kg ha−1), and 28% urea ammonium nitrate (UAN, 2.5% v/v). Adjuvants were combined with14C-herbicide and commercially formulated herbicide product. Leaves were harvested 2 DAT, rinsed with 10% aqueous methanol to remove surface deposits of herbicide, and dipped in 9:1 hexane:acetone to solubilize cuticular waxes. Imazethapyr absorption increased by 38 to 68% when UAN was combined with COC, NIS, or MSO. Total absorption of imazethapyr plus COC, MSO, or NIS exceeded 86% 2 DAT when UAN was added. Urea ammonium nitrate reduced the amount of imazethapyr associated with the cuticular wax by 2.0%. Imazethapyr absorption was similar on both the abaxial and adaxial leaf surface when UAN was not added; however, 12% more imazethapyr was absorbed from the abaxial leaf surface than from the adaxial leaf surface when UAN was combined with Sylgard 309. Uptake of 2,4-D ranged from 54 to 78% and was greatest with Silwet 408 and 3:1 mixture of ADE40: Silwet L-77. Picloram absorption ranged from 3 to 19%. Buffering picloram treatment solutions to pH 7 and including 2.5 kg ha-1ammonium sulfate increased picloram absorption to 37%.

New and noteworthy Melastomataceae from the Yanachaga-Chemillén National Park and surrounding areas in Oxapampa, Pasco, Peru

Phytotaxa ◽  
2018 ◽  
Vol 374 (3) ◽  
pp. 185 ◽  
Author(s):  
FABIÁN A. MICHELANGELI ◽  
RENATO GOLDENBERG
Keyword(s):  
National Park ◽  
Leaf Surface ◽  
Nodal Line ◽  
Abaxial Surface ◽  
North East ◽  
The North ◽  
The Andes ◽  
Abaxial Leaf Surface ◽  
Surrounding Areas ◽  
Sclerophyllous Forests

We describe six new species of Melastomataceae from the Yanachaga-Chemillén National Park and surrounding areas from the Department of Pasco, Province of Oxapampa in Central Peru. Macrocentrum andinum is the first species of the genus described from the Andes, found along creeks at 400–500 m elev. and characterized by its anysophyllous leaves, pubescent stems and four-merous flowers. Meriania rubriflora is found in forests above 2200 m elev. and it is characterized by stem nodes with stipular flaps, leaves with an acute base and four merous, deep red flowers. Miconia palcazuana is found along rivers and streams at 300–400 m on the eastern flank of the park, and it can be distinguished by its flowers with pink anthers with glands on the connective and narrowly oblanceolate to elliptic-lanceolate leaves. Miconia yanachagaensis grows in the dwarf-sclerophyllous forests at the top of ridges and grasslands over 2800 m elev. and it is characterized by its long dendritic-pedicellate trichomes on the abaxial leaf surface, the stems flattened to terete and the presence of a conspicuous annular nodal line. Triolena rojasae is found growing on rocks along the Palcazú River and its tributaries, and it is characterized by its lanceolate-crenate leaves. Triolena vasquezii grows on the northern end of the Huancabamba canyon and the North East portion of the park and can be distinguished by its pustulate leaves with purple abaxial surface and anthers with two ventral appendages. We also present the first report of the genus Wurdastom for Peru.

scholarly journals Effect of Fungicide Mobility and Application Timing on the Management of Grape Powdery Mildew

Plant Disease ◽  
2020 ◽  
Vol 104 (4) ◽  
pp. 1167-1174 ◽  
Author(s):  
Brent Warneke ◽  
Lindsey D. Thiessen ◽  
Walter F. Mahaffee
Keyword(s):  
Powdery Mildew ◽  
Leaf Surface ◽  
Quality Standards ◽  
Pinot Noir ◽  
Abaxial Surface ◽  
Phenological Stages ◽  
Application Timing ◽  
Abaxial Leaf Surface ◽  
Detached Leaves ◽  
Grape Powdery Mildew

Grape powdery mildew (GPM) fungicide programs consist of 5 to 15 applications, depending on region or market, in an attempt to achieve the high fruit quality standards demanded by the market. Understanding how fungicides redistribute and targeting redistributing fungicide to critical crop phenological stages could improve fungicide protection of grape clusters. This study evaluated fungicide redistribution in grapevines from major fungicide groups labeled for GPM control. Translaminar and xylem redistribution was examined by placing fungicide-impregnated filter disks on the adaxial or abaxial leaf surface of detached leaves for 10 min and then incubating for 48 h before inoculating the abaxial surface with conidia. Vapor redistribution used Teflon disks sprayed with fungicides and placed on the abaxial leaf surface of detached leaves 48 h before inoculation. Disease development was rated 10 days later. Translaminar movement through calyptra was tested using flowering potted vines. All fungicides tested redistributed through at least one mechanism. Fungicide timing at critical phenological stages (early, mid, and late bloom) was assessed in small plots of cultivar Pinot noir vines. The application of trifloxystrobin, quinoxyfen, or fluopyram at different bloom stages showed that applications initiated at end of bloom resulted in the lowest berry infection probabilities of 0.073, 0.097, and 0.020, respectively. The results of this study suggest that integrating two carefully timed applications of redistributing fungicides initiated at end of bloom into a fungicide program may be an effective strategy for wine grape growers in western Oregon to produce fruit with low GPM infection.

scholarly journals Foliar epidermis morphology in Quercus (subgenus Quercus, section Quercus) in Iran

2012 ◽  
Vol 71 (1) ◽  
pp. 95-113 ◽  
Author(s):  
Parisa Panahi ◽  
Ziba Jamzad ◽  
Mohammad Pourmajidian ◽  
Asghar Fallah ◽  
Mehdi Pourhashemi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Statistical Analysis ◽  
Leaf Surface ◽  
Epicuticular Waxes ◽  
Abaxial Leaf Surface ◽  
Trichome Types ◽  
Foliar Morphology ◽  
Scanning Electron ◽  
Foliar Epidermis

Foliar epidermis morphology inQuercus(subgenusQuercus, sectionQuercus) in IranThe foliar morphology of trichomes, epicuticular waxes and stomata inQuercus cedrorum, Q. infectoriasubsp.boissieri, Q. komarovii, Q. longipes, Q. macranthera, Q. petraeasubsp.ibericaandQ. robursubsp.pedunculiflorawere studied by scanning electron microscopy. The trichomes are mainly present on abaxial leaf surface in most species, but rarely they appear on adaxial surface. Five trichome types are identified as simple uniseriate, bulbous, solitary, fasciculate and stellate. The stomata of all studied species are of the anomocytic type, raised on the epidermis. The stomata rim may or may not be covered with epicuticular. The epicuticular waxes are mostly of the crystalloid type but smooth layer wax is observed inQ. robursubsp.pedunculiflora.Statistical analysis revealed foliar micromorphological features as been diagnostic characters inQuercus.

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