THE APPLICATION OF SEROLOGICAL METHODS TO THE DIFFERENTIATION OF CLOSELY RELATED SMUT FUNGI

1938 ◽  
Vol 16c (10) ◽  
pp. 391-404 ◽  
Author(s):  
E. C. Beck

Serological methods were applied in an attempt to differentiate a number of closely related members of the family Ustilaginaceae. The results of two series of reciprocal precipitin-ring tests showed that different genera and species of the same family were satisfactorily differentiated by this technique; so also were compatible cultures of the same species, where no detectable differences existed, other than the necessity of the haploid counterparts being brought together on the appropriate host plant to induce the diploid phase, and subsequent infection of the host. A parent culture and its mutant that were different morphologically but alike in their pathogenicity, were the only ones that could not be differentiated by this technique. Reciprocal absorption tests were applied to these two fungi, but the powder of either culture absorbed the antibodies of both from the immune sera. Optimal proportions of antigen and antibody were determined, but could not be applied in absorption tests because of the dilution of antisera. Agglutination tests were attempted but were unfruitful.

Insects ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 256 ◽  
Author(s):  
Aroa Domínguez ◽  
Sergio López ◽  
Ana Bernabé ◽  
Ángel Guerrero ◽  
Carmen Quero

The tomato leafminer Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is one of the most important pests of tomato worldwide. However, in spite of its tremendous economic importance, the success of environmentally friendly measures to control the pest is still limited. Study of physiological and behavioral parameters that affect pheromone production has provided useful information for pest management. Our results show no clear difference in pheromone production by females over the period from 2 h before to 2 h after the scotophase. However, pheromone production was clearly dependent on female age, with young females producing the highest amount of each pheromone component 10 days after emergence. In the presence of the host plant (physical contact and olfaction of the plant volatiles), virgin and mated females produced higher amounts of the major component of the pheromone (TDTA) than those in the absence of plant and those devoid of olfaction (antennectomized) but in physical contact with the plant. In electrophysiological experiments, TDTA elicited slightly lower responses on male antennae than the pheromone mixture. When stimulated at certain time intervals after the first exposure to TDTA, male antennae became more sensitive to the stimulus (sensitization effect). For the first time in an insect of the family Gelechiidae, we have found that females are able to detect their own pheromone (autodetection). Altogether, our results may represent a step forward in the knowledge of the chemical communication of this important pest.


2019 ◽  
Vol 24 (4) ◽  
pp. 529
Author(s):  
Mahran Zeity ◽  
Nagappa Srinivasa

Sixteen species of Tetranychoidea, 11 Tetranychidae and 5 Tenuipalpidae are reported in this study. Seven of them are recorded for the first time from Syria: Bryobia gigas, Oligonychus afrasiaticus, O. coniferarum, O. pratensis, Cenopalpus rubusi, Tenuipalpus cupressoides and T. punicae. New host plant records are also reported. Reinstatement of the genus Nuciforaella Vacante is discussed in this study. Detailed descriptions of immature stages and female of Nuciforaella nikitensis are given. A key to the known species of the family Tetranychidae from Syria is provided.


1998 ◽  
Vol 14 (4) ◽  
pp. 427-443 ◽  
Author(s):  
Hans-Peter Heckroth ◽  
Brigitte Fiala ◽  
Penny J. Gullan ◽  
Azarae HJ. Idris ◽  
Ulrich Maschwitz

Myrmecophytic species of the Paleotropical plant genus Macaranga (Euphorbiaceae) have hollow stems that are almost always occupied by ants of the genus Crematogaster and scale insects of the family Coccidae (Hemiptera: Coccoidea). The coccids have a cryptic endophytic lifestyle and are confined to this microhabitat. They are much more diverse than previously recognised. First data are presented on the diversity, prevalence, specificity and distribution of the coccids associated with myrmecophytic Macaranga species. Twenty-two species of Coccidae in total, including 15 previously unknown from Macaranga, were discovered from 19 species of Macaranga in Peninsular Malaysia and Borneo. The original describers tentatively assigned the known coccid species to Coccus (Coccinae) but the Macaranga coccids still require taxonomic research to establish their correct placing. The coccids varied in their host-plant specificity from species that occurred in most of the sampled Macaranga to one species that was found almost exclusively only on a single host species. In addition to their occurrence on Macaranga, only three species, C. macarangae and C. secretus and morphospecies C. 214 were found on rare occasions in the stem interior of a few other myrmecophytes and in a non-myrmecophytic liana, but did not regularly colonise these plants. Most of the coccids can be regarded as highly specific at the plant genus level.


2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Elena Geiser ◽  
Florian Ludwig ◽  
Thiemo Zambanini ◽  
Nick Wierckx ◽  
Lars M. Blank

Some smut fungi of the family Ustilaginaceae produce itaconate from glucose. De novo genome sequencing of nine itaconate-producing Ustilaginaceae revealed genome sizes between 19 and 25 Mbp. Comparison to the itaconate cluster of U. maydis MB215 revealed all essential genes for itaconate production contributing to metabolic engineering for improving itaconate production.


Insects ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1116
Author(s):  
Elkin Aguirre-Ramirez ◽  
Sandra Velasco-Cuervo ◽  
Nelson Toro-Perea

Anastrepha obliqua (Macquart) (Diptera: Tephritidae) is an important pest in the neotropical region. It is considered a polyphagous insect, meaning it infests plants of different taxonomic families and readily colonizes new host plants. The change to new hosts can lead to diversification and the formation of host races. Previous studies investigating the effect of host plants on population structure and selection in Anastrepha obliqua have focused on the use of data from the mitochondrial DNA sequence and microsatellite markers of nuclear DNA, and there are no analyses at the genomic level. To better understand this issue, we used a pooled restriction site-associated DNA sequencing (pooled RAD-seq) approach to assess genomic differentiation and population structure across sympatric populations of Anastrepha obliqua that infest three host plants—Spondias purpurea (red mombin), Mangifera indica (mango) of the family Anacardiaceae and Averrhoa carambola (carambola) of the family Oxalidaceae—in sympatric populations of the species Anastrepha obliqua of Inter-Andean Valley of the Cauca River in southwestern Colombia. Our results show genomic differentiation of populations from carambola compared to mango and red mombin populations, but the genetic structure was mainly established by geography rather than by the host plant. On the other hand, we identified 54 SNPs in 23 sequences significantly associated with the use of the host plant. Of these 23 sequences, we identified 17 candidate genes and nine protein families, of which four protein families are involved in the nutrition of these flies. Future studies should investigate the adaptive processes undergone by phytophagous insects in the Neotropics, using fruit flies as a model and state-of-the-art molecular tools.


1970 ◽  
Vol 132 (4) ◽  
pp. 636-662 ◽  
Author(s):  
J. P. Dubey ◽  
Nancy L. Miller ◽  
J. K. Frenkel

Coccidian oocysts resembling those of Isospora bigemina were excreted by cats fed Toxoplasma. In order to identify these oocysts with Toxoplasma infectivity a number of critical comparisons were made. The appearance of oocysts and Toxoplasma infectivity was simultaneous in the feces of 23 of 24 adult cats, 3–5 days after feeding of Toxoplasma cysts; in the feces of 4 out of 9 cats, 7–10 days after feeding of trophozoites; and in 8 out of 17 cats, 20–24 days after feeding of cat feces containing oocysts. Oocysts and infectivity were present in similar numbers, and they disappeared simultaneously from the feces of cats. Oocysts and infectivity were also observed simultaneously in the feces of 9 kittens, 1–2 days old, fed Toxoplasma cysts. Oocysts could not be separated from infectivity by filtration, by continuous particle electrophoresis, or by density gradient centrifugation. Excystation of oocysts was followed by an increase in titer of Toxoplasma infectivity. Unsporulated oocysts in fresh cat feces were noninfectious to mice, but oocyst sporulation was associated quantitatively with the development of infectivity at different temperatures and conditions of oxygenation. Maximum oocyst sporulation at 48 hr correlated with the development of maximum Toxoplasma infectivity. 1 and 2% sulfuric acid, and 2.5% potassium dichromate were found to be the best preservatives for sporulation of oocysts and for the development of Toxoplasma infectivity. Low sporulation rates in 0.1% formalin, 20% ethanol, and in water were associated with low infectivity in these reagents. Neither Toxoplasma infectivity nor oocysts developed in 0.3% formalin, 1% ammonium hydroxide, or 1% iodine in 20% ethanol. Oocysts, sporocysts, and sporozoites were stained specifically with Toxoplasma antibody in the indirect fluorescent antibody test. Typical coccidian stages, schizonts, and male and female gametocytes were found in the epithelium of the small intestine of kittens fed Toxoplasma cysts. The classification of T. gondii is discussed in relation to that of other isosporan coccidia of cats and dogs. The term "Toxoplasma oocyst" is introduced and Toxoplasma is classified in the family Toxoplasmidae of the suborder Eimeriina. The species Isospora bigemina is restricted to dogs, and I. cati to cats. I. felis and so-called I. rivolta from cats were noninfectious to dogs, and did not confer immunity to subsequent infection with I. canis and I. rivolta from dogs.


2019 ◽  
Vol 70 (3) ◽  
pp. 175-178
Author(s):  
Daisuke Sasaki

In April 2018, the occurrence of Sinomegoura citricola was recorded on Ilex rotunda (Aquifoliaceae) in Japan. Both aphid identification with mounted specimens and rearing experiments with the plant shoots revealed that I. rotunda is a definite host for S. citricola. This is believed to be the first study to report a species of the family Aquifoliaceae as a certain host plant of S. citricola, emphasizing that the aphid is a polyphagous species.


2020 ◽  
Vol 69 (3) ◽  
pp. 193-229
Author(s):  
Miloš Černý ◽  
Michael von Tschirnhaus ◽  
Kaj Winqvist

Abstract First records of 151 species in the family Agromyzidae are presented for 40 countries and major islands in the Palaearctic Region (Russia being split into four subregions): from Afghanistan (1 sp.), Albania (15 spp.), Algeria (1 sp.), Andorra (2 spp.), Armenia (4 spp.), Austria (14 spp.), Balearic Islands (4 spp.), Canary Islands (2 spp.), China - Palaearctic part (2 spp.), Corsica (5 spp.), Crete (6 spp.), Croatia (16 spp.), Czech Republic (4 spp.), Dodekanese Islands incl. Rhodes (5 spp.), Egypt (1 sp.), European Russia (2 spp.), Finland (12 spp.), France (1 sp.), Georgia (1 sp.), Germany (14 spp.), Great Britain (2 spp.), Greece (4 spp.), Iceland (1 sp.), Iran (8 spp.), Israel (1 sp.), Italy (12 spp.), Jordan (6 spp.), Kyrgyzstan (6 spp.), Lithuania (2 spp.), Macedonia (2 spp.), Mongolia (2 spp.), Morocco (6 spp.), Netherlands (1 sp.), Norway (3 spp.), Oman (1 sp.), Poland (1 sp.), West Siberia (1 sp.), East Sibiria (3 spp.), Kamchatka (5 spp.), Sardinia (1 sp.), Slovakia (4 spp.), South Korea (13 spp.), Spain (10 spp.), Sweden (7 spp.), Switzerland (5 spp.) and Turkey (1 sp.). For a few species morphological details or plant genera from the collecting localities are added as possible host plants. Phytomyza parvicella (Coquillett, 1902) exhibits an extremely disjunct distribution, occurring in the high Arctic from Alaska to west Greenland and on the highest mountains of Germany and Poland. Other rare species with Boreo-alpine disjunctions are recorded. Cerodontha (Cerodontha) phragmitophila Hering, 1935 reached a tiny artificial patch of its host plant within the Sahara sand desert. The thermophilic mediterranean Phytoliriomyza pectoralis (Becker, 1908) was detected on the Swedish sun-blessed island Öland. Chromatomyia obscuriceps (Hendel, 1936) (emerged from Triticum crop) is specified as a valid species occurring from Iceland to Kamchatka. A new definition for Chromatomyia nigra (Meigen, 1830) sensu stricto is presented. The American Amauromyza (Cephalomyza) abnormalis (Malloch, 1913), a possible agent against the harmful neophyte Amaranthus retroflexus, was detected for the first time in the Palaearctic Region. Gnaphalium is attributed as a first detected host plant genus of Phytoliriomyza venustula Spencer, 1976.


Zootaxa ◽  
2020 ◽  
Vol 4878 (3) ◽  
pp. 595-600
Author(s):  
M. B. MALIPATIL

Parasadoletus exsertus gen. and sp. nov. (Hemiptera: Heteroptera: Lygaeoidea: Heterogastridae) is described from Mount Glorious, southeastern Queensland, Australia, based on specimens collected associated with a rainforest tree Argyrodendron actinophyllum (F. M. Bailey) Edlin (Malvaceae). The new genus is compared and its relationship with other known genera of the family Heterogastridae elucidated, also comments on host plant associations within this family are provided.


2015 ◽  
Vol 105 (7) ◽  
pp. 998-1012 ◽  
Author(s):  
Yigal Cohen ◽  
Kyle M. Van den Langenberg ◽  
Todd C. Wehner ◽  
Peter S. Ojiambo ◽  
Mary Hausbeck ◽  
...  

The downy mildew pathogen, Pseudoperonospora cubensis, which infects plant species in the family Cucurbitaceae, has undergone major changes during the last decade. Disease severity and epidemics are far more destructive than previously reported, and new genotypes, races, pathotypes, and mating types of the pathogen have been discovered in populations from around the globe as a result of the resurgence of the disease. Consequently, disease control through host plant resistance and fungicide applications has become more complex. This resurgence of P. cubensis offers challenges to scientists in many research areas including pathogen biology, epidemiology and dispersal, population structure and population genetics, host preference, host−pathogen interactions and gene expression, genetic host plant resistance, inheritance of host and fungicide resistance, and chemical disease control. This review serves to summarize the current status of this major pathogen and to guide future management and research efforts within this pathosystem.


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