A two front battle: identification of novel components of resistance against Oidium neolycopersici in tomato and Arabidopsis

2021 ◽  
Author(s):  
Miguel I. Santillán Martínez
Keyword(s):  
Oidium Neolycopersici ◽  
Components Of Resistance

scholarly journals Formation of Conidial Pseudochains by Tomato Powdery Mildew Oidium neolycopersici

Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 915-919 ◽  
Author(s):  
W. Oichi ◽  
Y. Matsuda ◽  
T. Nonomura ◽  
H. Toyoda ◽  
L. Xu ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Powdery Mildew ◽  
Critical Level ◽  
Oidium Neolycopersici ◽  
Ambient Relative Humidity ◽  
Digital Microscope ◽  
Tomato Powdery Mildew ◽  
A Chain ◽  
Weak Wind ◽  
Generative Cells

The formation of conidial pseudochains by the tomato powdery mildew Oidium neolycopersici on tomato leaves was monitored using a high-fidelity digital microscope. Individual living conidiophores that formed mature conidial cells at their apex were selected for observation. The conidial cells were produced during repeated division and elongation by the generative cells of the conidiophores. Under weak wind conditions (0.1 m/s), these conidial cells did not separate from each other to produce a chain of conidial cells (pseudochain). The pseudochains dropped from the conidiophores once four conidial cells were connected. The conidiophores resumed conidium production, followed by another cycle of pseudochain formation. The formation of pseudochains by tomato powdery mildew was not influenced by the ambient relative humidity. On the other hand, the conidial cells produced were easily wind dispersed without forming pseudochains when conidiophores were exposed to stronger winds (1.0 m/s). The present study successfully demonstrated that the pathogen required wind to disperse progeny conidia from the conidiophores and produced conidial pseudochains when the wind was below a critical level, independent of high relative humidity as reported previously.

The behavioural responses of three different strains of Musca domestica (Diptera: Muscidae) to Alfacron bait in the laboratory

1992 ◽  
Vol 82 (4) ◽  
pp. 471-478 ◽  
Author(s):  
Z.A. Freeman ◽  
D.B Pinniger
Keyword(s):  
Musca Domestica ◽  
Resistant Strain ◽  
Behavioural Responses ◽  
Components Of Resistance ◽  
Minute Period ◽  
Proboscis Extension ◽  
Number Of Visits ◽  
Time Spent Feeding ◽  
Different Strains ◽  
Cage Test

AbstractA study was carried out to investigate the behavioural components of resistance in the Standlake strain of Musca domestica Linnaeus. The flies were collected from a poultry unit where azamethiphos spray-on-bait (Alfacron), had been regularly used to control the fly population. A no-choice laboratory cage test was used to observe the responses of the Standlake resistant strain to baits and compare it with two other strains namely, Sparsholt resistant and Cooper susceptible. The baits used were, Alfacron, sugar and analytical grade azamethiphos, sugar alone, and a blank target as control. Only female flies were used, each strain was exposed separately to each bait over a 50 minute period and the responses were recorded with a datalogger. The responses (per fly) recorded during each test period were: the number of visits to a bait; the time spent on a bait; the number of feeds and time spent feeding on the bait defined as the number of proboscis contacts and the length of time of proboscis contact with the bait. Knockdown of flies was recorded at the end of each test. All strains showed differences in their responses to baits. The Standlake strain showed the greatest difference to responses to Alfacron, with inhibition of proboscis extension when flies landed on the bait and a lower proboscis contact when extended, resulting in fewer flies being knocked down by Alfacron than by the sugar and azamethiphos bait. This suggested that inhibition of feeding on the Alfacron bait by the Standlake strain was caused by formulation components or contaminants and not the active insecticide ingredient, azamethiphos.

scholarly journals Effect of Temperature and Hose Genotype on Components of Resistance to Groundnut Rust

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
P Subrahmanyam ◽  
PV Subba Rao ◽  
PM Reddy ◽  
D McDonald
Keyword(s):  
Effect Of Temperature ◽  
Components Of Resistance ◽  
Groundnut Rust

Components of resistance to Aphis fabae in faba bean cultivars

1986 ◽  
Vol 40 (1) ◽  
pp. 35-40 ◽  
Author(s):  
J. Holt ◽  
S. D. Wratten
Keyword(s):  
Faba Bean ◽  
Aphis Fabae ◽  
Components Of Resistance

Physical control of powdery mildew (Oidium neolycopersici) on tomato leaves by exposure to corona discharge

2008 ◽  
Vol 30 (4) ◽  
pp. 517-524 ◽  
Author(s):  
T. Nonomura ◽  
Y. Matsuda ◽  
K. Kakutani ◽  
Y. Takikawa ◽  
H. Toyoda
Keyword(s):  
Powdery Mildew ◽  
Corona Discharge ◽  
Oidium Neolycopersici ◽  
Physical Control

Resistance mechanisms in Lycopersicon spp. to tomato powdery mildew (Oidium neolycopersici)

2002 ◽  
Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽  
pp. S141-S144 ◽  
Author(s):  
A. Lebeda ◽  
B. Mieslerová ◽  
L. Luhová ◽  
K. Mlíčková
Keyword(s):  
Germ Tube ◽  
Leaf Surface ◽  
Resistance Mechanism ◽  
Resistance Mechanisms ◽  
Host Tissue ◽  
Tissue Response ◽  
Limited Information ◽  
Oidium Neolycopersici ◽  
Conidium Germination ◽  
Tomato Powdery Mildew

Limited information on the resistance mechanisms in Lycopersicon spp. to Oidium neolycopersici is still available. Macroscopically the resistance is characterized by a very low amount of mycelium development and a lack of sporulation. The leaf surface did not effectively inhibite conidium germination, however significant differences in germ tube and appressorium development were recorded. A large variation was observed in host tissue response. The prevailing resistance mechanism was hypersensitivity (HR). Considerable changes of peroxidase and catalase activities during pathogenesis were detected among tested wild Lycopersicon spp. There was positive correlation between increasing of peroxidase activity and extent of necrosis. Histochemistry showed large differences in production of superoxid ions, H<sub>2</sub>O<sub>2</sub> and peroxidase in Lycopersicon spp. with various level of resistance.

scholarly journals Components of resistance to the sorghum head bug, Calocoris angustatus

2000 ◽  
Vol 19 (6) ◽  
pp. 385-392 ◽  
Author(s):  
A.P. Padma Kumari ◽  
H.C. Sharma ◽  
D.R.R. Reddy
Keyword(s):  
Calocoris Angustatus ◽  
Components Of Resistance

scholarly journals First Report of Powdery Mildew Caused by Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii on Papaya in Taiwan

Plant Disease ◽  
2011 ◽  
Vol 95 (9) ◽  
pp. 1188-1188 ◽  
Author(s):  
J.-G. Tsay ◽  
R.-S. Chen ◽  
H.-L. Wang ◽  
W.-L. Wang ◽  
B.-C. Weng
Keyword(s):  
Powdery Mildew ◽  
Morphological Characteristics ◽  
Its Region ◽  
Podosphaera Xanthii ◽  
Oidium Neolycopersici ◽  
First Report ◽  
Plastic Bags ◽  
The World ◽  
Golovinomyces Cichoracearum ◽  
Powdery Mildew Fungi

Powdery mildew can be found in most papaya (Carica papaya L.) fields during the winter and spring seasons in Taiwan. It usually causes severe yellowing of the leaf lamina and petiole and serious defoliation. Three types of powdery mildew fungi were isolated from papaya leaves in Chiayi City (23.28°N, 120.28°E) at the beginning of 2008. Conidia of the first one were single, globose, hyaline, and 24 to 36 × 14 to 18 μm (average 30.2 × 15.6 μm) without fibrosin bodies and with straight or occasionally flexuous conidiophores at the base. The second one had short pseudo-chains of two to four conidia which were ellipsoidal to ovoid, hyaline, and 24 to 40 × 12 to 16 μm (average 29.7 × 13.4 μm) without fibrosin bodies. The third type had chains of ellipsoidal conidia that were hyaline, 24 to 28 × 12 to 16 μm (average 26.3 × 14.4 μm) and contained fibrosin bodies. To confirm the identity of the three fungi, the internal transcribed spacer (ITS) region of rDNA was amplified using the primer pairs G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/Ed2 (5′-CGC GTA GAG CCC ACG TCG GA-3′), G1 (5′-TCC GTA GGT GAA CCT GCG GAA GGA T-3′)/On2 (5′-TGT GAT CCA TGT GAC TGG AA-3′), and S1 (5′-GGA TCA TTA CTG AGC GCG AGG CCC CG-3′)/S2 (5′-CGC CGC CCT GGC GCG AGA TAC A-3′). The alignment of obtained sequences (GenBank Accession Nos. GU358452, 507 bp; GU358451, 580 bp; and GU358450, 455 bp) showed a sequence identity of 100, 99, and 99% with the ITS sequences of Erysiphe diffusa, Oidium neolycopersici, and Podosphaera xanthii (GenBank Accession Nos. FJ378880, EU909694, and GQ927254), respectively. On the basis of morphological characteristics and ITS sequence similarities, these fungi were identified as E. diffusa (Cooke & Peck) U. Braun & S. Takam., O. neolycopersici L. Kiss, and P. xanthii (Castagne) U. Braun & S. Takam., respectively (1,3). Single colonies on papaya leaves infected with powdery mildew were identified in the laboratory and maintained on papaya leaves as inoculum. Pathogenicity was confirmed through inoculations by gently pressing a single colony of each fungus onto leaves of healthy papaya seedlings (cv. Horng-Fe). Five seedlings were inoculated for each fungus and then covered with plastic bags for 2 days. Five noninoculated seedlings served as control. After inoculation, treated plants were maintained separately from the control in different rooms of a greenhouse at 25°C under natural daylight conditions. Seven days after inoculation, typical symptoms of powdery mildew were observed on inoculated plants, but not on noninoculated plants. The same species from diseased lesions following artificial inoculation with each fungus were identified with light microscopy. Papaya was previously described as a host to O. caricae Noack in many tropical and subtropical areas of the world including Taiwan (2). However E. cruciferarum, Golovinomyces cichoracearum, Oidiopsis sicula, O. caricae, O. caricae-papayae, O. caricicola, O. indicum, O. papayae, Ovulariopsis papayae, P. caricae-papayae, P. macularis, P. xanthii, and Streptopodium caricae were reported to infect papaya (4). To our knowledge, this is the first report of papaya powdery mildew caused by E. diffusa and O. neolycopersici in the world and the first report of the three fungi found on papaya in Taiwan. References: (1) U. Braun and S. Takamatsu. Schlechtendalia 4:1, 2000. (2) H. S. Chien and H. L. Wang. J. Agric. Res. China 33:320, 1984. (3) L. Kiss et al. Mycol. Res. 105:684, 2001. (4) J. R. Liberato et al. Mycol. Res. 108:1185, 2004.

2P1-K06 High Sensitivity Slip Sensor utilizing Characteristics of Pressure Conductive Rubber : High Frequency Components of Resistance Change

2009 ◽  
Vol 2009 (0) ◽  
pp. _2P1-K06_1-_2P1-K06_2
Author(s):  
Seiichi Teshigawara ◽  
Satoru Shimizu ◽  
Kenjiro Tadakuma ◽  
Aiguo Ming ◽  
Masatoshi Ishikawa ◽  
...  
Keyword(s):  
High Frequency ◽  
High Sensitivity ◽  
Resistance Change ◽  
Components Of Resistance ◽  
Conductive Rubber ◽  
Frequency Components ◽  
Slip Sensor
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