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O E Krips - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Cultivars of Ornamental Crop Gerbera jamesonii on Production of Spider Mite-Induced Volatiles, and Their Attractiveness to the Predator, Phytoseiulus persimilis
Journal of Chemical Ecology, 2001Co-Authors: O E Krips, P E L Willems, Rieta Gols, M. A. Posthumus, G. Gort, M. DickeAbstract:We investigated whether volatiles produced by spider mite-damaged plants of four gerbera cultivars differ in attractiveness to Phytoseiulus persimilis , a specialist predator of spider mites, and how the mite-induced odor blends differ in chemical composition. The gerbera cultivars differed in resistance, as expressed in terms of spider mite intrinsic rate of population increase ( r _m). In order of increasing resistance these were Sirtaki, Rondena, Fame, and Bianca. To correct for differences in damage inflicted on the cultivars, we developed a method to compare the attractiveness of the blends, based on the assumption that a larger amount of spider mite damage leads to higher attraction of P. persimilis . Spider mite-induced volatiles of cultivars Rondena and Bianca were preferred over those of cultivar Sirtaki. Spider mite-induced volatiles of cultivars Sirtaki and Fame did not differ in attractiveness to P. persimilis . Sirtaki plants had a lower relative production of terpenes than the other three cultivars. This was attributed to a low production of cis -α-bergamotene, trans -α-bergamotene, trans -β-bergamotene, and ( E )-β-farnesene. The emission of ( E )-β-ocimene and linalool was lower in Sirtaki and Fame leaves than in Bianca and Rondena. The importance of these chemical differences in the differential attraction of predatory mites is discussed.
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plant effects on biological control of spider mites in the Ornamental Crop gerbera
Plant effects on biological control of spider mites in the ornamental crop gerbera., 2000Co-Authors: O E KripsAbstract:Introduction The spider mite Tetranychus urticae Koch is an important pest in many greenhouse Crops. In vegetables it can be successfully controlled with the predatory mite Phytoseiulus persimilis Athias-Henriot, a specialist predator of spider mites (Helle & Sabelis, 1985). However, on Ornamental Crops where aesthetic damage is not tolerated, biological control is more difficult. Pest control on Ornamentals mainly relies on the use of pesticides (van de Vrie, 1985). In the Ornamental Crop gerbera, Gerbera jamesonii Bolus, biological control stands a better chance, since gerbera cutflowers are sold without leaves. The leaves stay behind on the plants in the greenhouse, when flowers are harvested. Therefore, zero tolerance for aesthetic damage does apply for gerbera cutflowers but not for the leaves (van de Vrie, 1985). In gerbera, spider mites usually only damage leaves and do not feed on flowers. The spider mites only migrate to the flowers when the leaves become overexploitated. Gerbera growers will interfere with control methods long before overexploitation takes place. If they apply biological control, there will be some damage by spider mites on the plant leaves. But spider mite damage on the leaves can be accepted, as long as it does not lead to an intolerable lower flower production by the plants. Therefore, biological control may be a suitable method to control spider mites in gerbera. Many cultivars of gerbera are commercially available. At present these cultivars are mainly selected for the colour and shape of the flowers. However, the cultivars also differ in several plant characteristics that have not been selected for, such as leaf shape and density of trichomes on the undersurface of the leaves (Sutterlin and van Lenteren, 1997; Krips et al. , 1999a). Earlier studies showed that the success of natural enemies in biological control can be influenced strongly by characteristics of the host plant (Bergman and Tingey, 1979, Boethel and Eikenbary, 1986;van Lenteren and de Ponti, 1990; Hare, 1992; Walter, 1996). If gerbera cultivars differ in such characteristics, biological control may not be equally successful on all cultivars. The objective of this PhD study was to investigate which differences between gerbera cultivars result in differences in the success of biological control of T. urticae with the predatory mite P. persimilis. We have focussed on the following three host plant characteristics: Host plant resistance to T. urticae Density of leaf hairs on the under surface of leaves Production of volatiles by leaves with spider mite damage We determined to which extent gerbera cultivars differ in each of these characteristics. In addition, we assessed the effect of these characteristics on certain aspects of the interaction between spider mites and their predators on gerbera. 1. Host plant resistance to T. urticae The intrinsic rate of population increase, r m , of T. urticae was determined on nine gerbera cultivars. The r m differed largely per cultivar and varied from 0.09-0.23/day. Hence, gerbera cultivars differ largely in resistance to T. urticae. However even on the most resistant cultivar additional methods of spider mite control will eventually be necessary. An obvious additional method is biological control with the predatory mite P. persimilis. But this is only possible if plant resistance to spider mites and biological control are compatible in gerbera. To investigate whether resistance and biological control of spider mites are compatible in gerbera, we determined the r m of the predatory mite P. persimilis on four gerbera cultivars on which the r m of T. urticae differed largely. Cultivar differences in r m of the predators were negligible, the r m varied from 0.43/day to 0.45/day. This indicates that a combined use of resistance and biological control of spider mites might be possible in gerbera. In contrast to what is commonly assumed, the speed at which spider mites are exterminated by P. persimilis is not higher on resistant cultivars than on susceptible cultivars. At first this seems to be an argument against breeding for resistance to spider mites in any Crop. However, the advantage of resistant cultivars lies more in the time before predator introduction is necessary, so, to delay the moment that addidtional control methods are necessary, than in the success of biological control after predators are introduced. 2. Density of leaf hairs on the under surface of leaves Gerbera cultivars differ largely in density of trichomes on the undersurface of leaves (Sutterlin & van Lenteren, 1997). We investigated whether prey searching behaviour of P. persimilis is affected on cultivars with a high density of trichomes. We determined the walking speed, walking activity and rate of encounter with prey on three cultivars with trichome densities of 105, 400 and 730 trichomes/cm 2. Furthermore, we assessed the predation rate on these three cultivars at three prey densities. Walking speed of the predators was highest on the cultivar with the lowest leaf hair density. Walking activity, defined as the percentage of time the predators spent walking, was not dependent on leaf hair density of the cultivars. The rate of encounter with prey was inversely related to trichome density. Predation rate of adult female P. persimilis was affected negatively by trichome density when prey density was low. However, at high prey density such an effect was absent, because the predation rate is not limited by the rate of encounter with prey at high prey density. The results of these experiments showed that the effect of trichome density on the predator-prey dynamics between T. urticae and P. persimilis on gerbera plants will be dependent on the density in which T. urticae occurs on these plants. In a small-scale greenhouse experiment we found indications that the density of T. urticae is limiting the population growth rate of the predators and that trichome density affects the growth of the predator populations on gerbera plants. 3. Production of volatiles by leaves with spider mite damage Many host plant species produce volatiles when herbivores damage the leaves. Natural enemies of the herbivores can use these volatiles to locate plants that are infested with their prey or hosts (see Vet & Dicke, 1992 and Dicke, 1994 for reviews). Such volatiles also are important in the interaction between T. urticae and P. persimilis (Sabelis and van de Baan, 1983; Sabelis et al . , 1984; Dicke and Sabelis, 1988; Dicke et al . , 1990a,b; Sabelis and van der Weel, 1994; Sabelis and Afman, 1994). Plants of several species produce volatiles when spider mites damage their leaves. Phytoseiulus persimilis is attracted to these volatiles (Dicke and Sabelis, 1988). Once the predators have found spider mite-infested leaves, they stay there until all prey is exterminated, which is most likely the result of attraction of the predators to volatiles from the spider mite patch and arrestment by these volatiles (Sabelis & van de Meer, 1986; Sabelis and Afman, 1994). We have investigated whether gerbera leaves with spider mite damage also produce volatiles that attract P. persimilis. In contrast to undamaged gerbera leaves that had a low production of volatiles, spider mite-damaged gerbera leaves produced many volatiles in large quantities. However, P. persimilis from our standard culture on Lima bean leaves with T. urticae was not attracted to these volatiles. In contrast, the predators responded strongly to the gerbera volatiles when they were given six days of experience with spider mites on gerbera leaves and therefore were exposed to the spider mite-induced volatiles for six days. We have investigated whether the chemical composition of the spider mite-induced volatiles differs between gerbera cultivars. Furthermore, we determined whether cultivar differences exist in attractiveness of the spider mite-induced volatiles to P. persimilis. In a two-choice situation the predators preferred the volatiles of cultivars Rondena and Bianca over those of cultivar Sirtaki. The volatiles from the cultivars Sirtaki and Fame did not differ in attrativeness. The blend emitted by spider mite-damaged Sirtaki leaves consisted of a much lower relative amount of terpenes than the blends of the other three cultivars, which was mostly due to a low production of cis-alpha-bergamotene, trans-alpha-bergamotene, trans-beta-bergamotene and (E) -beta-farnesene. Furthermore, the production of (E) -beta-ocimene and linalool was lower by Sirtaki and Fame leaves than by leaves of Bianca and Rondena. These two compounds attract P. persimilis when offered in a Y-tube olfactometer (Dicke et al. , 1990b) . Whether the poor attractiveness of the spider mite-induced volatiles of Sirtaki and Fame is related to the limited production of these compounds should be investigated in future studies.
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the response of phytoseiulus persimilis to spider mite induced volatiles from gerbera influence of starvation and experience
Journal of Chemical Ecology, 1999Co-Authors: O E Krips, P E L Willems, Maarten A. Posthumus, Rieta Gols, Marcel DickeAbstract:When leaves of the Ornamental Crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced.
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the response of phytoseiulus persimilis to spider mite induced volatiles from gerbera influence of starvation and experience
Journal of Chemical Ecology, 1999Co-Authors: O E Krips, P E L Willems, Rieta Gols, Maarten A. PosthumusAbstract:When leaves of the Ornamental Crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced. We studied the attraction of P. persimilis to the volatiles from spider mite-damaged gerbera leaves and how attraction is affected by starvation and previous experience. Phytoseiulus persimilis that were reared on spider mites (T. urticae) on Lima bean were not attracted to spider mite-induced volatiles from gerbera. Starvation did not influence the predator's response to these volatiles. In contrast, predators that were reared on spider mites on gerbera leaves were strongly attracted to volatiles from spider mite-infested gerbera. This was found also for predators that originated from a culture on spider mite-infested bean and were offered six days of experience with spider mites on gerbera leaves.
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compatibility of host plant resistance and biological control of the two spotted spider mite tetranychus urticae in the Ornamental Crop gerbera
Biological Control, 1999Co-Authors: O E Krips, P E L Willems, Marcel DickeAbstract:Abstract We investigated the compatibility of host plant resistance to the spider mite Tetranychus urticae Koch in the Ornamental Crop gerbera with the use of the predatory mite Phytoseiulus persimilis Athias-Henriot for biological control. We used four gerbera cultivars on which the intrinsic rate of population increase (rm) of T. urticae was previously found to differ largely. We performed life-history studies on those cultivars with P. persimilis and determined whether the developmental time, peak oviposition rate, and rm of the predator was influenced by host plant resistance. Because the first egg of P. persimilis is usually a male and therefore does not contribute to the population growth rate, we discarded the first egg of all predators from our analyses. The egg-to-second-egg developmental time of the predator was approximately 5.2 days. This developmental time was slightly but significantly shorter on gerbera cultivar Fame than on the other three cultivars. However, this shorter developmental time did not lead to a higher rm of the predators on this cultivar. No cultivar effect was found on the peak oviposition rate, which varied from 5.1 to 5.4 eggs/female/day. On the cultivars used, the rm of the spider mites was previously found to vary from 0.09 to 0.23 per day. We did not find any effect of spider mite resistance in gerbera on the rm of the predators, which ranged from 0.43 to 0.45 per day. Hence, the capacity for population increase of P. persimilis is not influenced by host plant resistance to its prey.
P E L Willems - One of the best experts on this subject based on the ideXlab platform.
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Comparison of Cultivars of Ornamental Crop Gerbera jamesonii on Production of Spider Mite-Induced Volatiles, and Their Attractiveness to the Predator, Phytoseiulus persimilis
Journal of Chemical Ecology, 2001Co-Authors: O E Krips, P E L Willems, Rieta Gols, M. A. Posthumus, G. Gort, M. DickeAbstract:We investigated whether volatiles produced by spider mite-damaged plants of four gerbera cultivars differ in attractiveness to Phytoseiulus persimilis , a specialist predator of spider mites, and how the mite-induced odor blends differ in chemical composition. The gerbera cultivars differed in resistance, as expressed in terms of spider mite intrinsic rate of population increase ( r _m). In order of increasing resistance these were Sirtaki, Rondena, Fame, and Bianca. To correct for differences in damage inflicted on the cultivars, we developed a method to compare the attractiveness of the blends, based on the assumption that a larger amount of spider mite damage leads to higher attraction of P. persimilis . Spider mite-induced volatiles of cultivars Rondena and Bianca were preferred over those of cultivar Sirtaki. Spider mite-induced volatiles of cultivars Sirtaki and Fame did not differ in attractiveness to P. persimilis . Sirtaki plants had a lower relative production of terpenes than the other three cultivars. This was attributed to a low production of cis -α-bergamotene, trans -α-bergamotene, trans -β-bergamotene, and ( E )-β-farnesene. The emission of ( E )-β-ocimene and linalool was lower in Sirtaki and Fame leaves than in Bianca and Rondena. The importance of these chemical differences in the differential attraction of predatory mites is discussed.
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the response of phytoseiulus persimilis to spider mite induced volatiles from gerbera influence of starvation and experience
Journal of Chemical Ecology, 1999Co-Authors: O E Krips, P E L Willems, Maarten A. Posthumus, Rieta Gols, Marcel DickeAbstract:When leaves of the Ornamental Crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced.
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the response of phytoseiulus persimilis to spider mite induced volatiles from gerbera influence of starvation and experience
Journal of Chemical Ecology, 1999Co-Authors: O E Krips, P E L Willems, Rieta Gols, Maarten A. PosthumusAbstract:When leaves of the Ornamental Crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced. We studied the attraction of P. persimilis to the volatiles from spider mite-damaged gerbera leaves and how attraction is affected by starvation and previous experience. Phytoseiulus persimilis that were reared on spider mites (T. urticae) on Lima bean were not attracted to spider mite-induced volatiles from gerbera. Starvation did not influence the predator's response to these volatiles. In contrast, predators that were reared on spider mites on gerbera leaves were strongly attracted to volatiles from spider mite-infested gerbera. This was found also for predators that originated from a culture on spider mite-infested bean and were offered six days of experience with spider mites on gerbera leaves.
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compatibility of host plant resistance and biological control of the two spotted spider mite tetranychus urticae in the Ornamental Crop gerbera
Biological Control, 1999Co-Authors: O E Krips, P E L Willems, Marcel DickeAbstract:Abstract We investigated the compatibility of host plant resistance to the spider mite Tetranychus urticae Koch in the Ornamental Crop gerbera with the use of the predatory mite Phytoseiulus persimilis Athias-Henriot for biological control. We used four gerbera cultivars on which the intrinsic rate of population increase (rm) of T. urticae was previously found to differ largely. We performed life-history studies on those cultivars with P. persimilis and determined whether the developmental time, peak oviposition rate, and rm of the predator was influenced by host plant resistance. Because the first egg of P. persimilis is usually a male and therefore does not contribute to the population growth rate, we discarded the first egg of all predators from our analyses. The egg-to-second-egg developmental time of the predator was approximately 5.2 days. This developmental time was slightly but significantly shorter on gerbera cultivar Fame than on the other three cultivars. However, this shorter developmental time did not lead to a higher rm of the predators on this cultivar. No cultivar effect was found on the peak oviposition rate, which varied from 5.1 to 5.4 eggs/female/day. On the cultivars used, the rm of the spider mites was previously found to vary from 0.09 to 0.23 per day. We did not find any effect of spider mite resistance in gerbera on the rm of the predators, which ranged from 0.43 to 0.45 per day. Hence, the capacity for population increase of P. persimilis is not influenced by host plant resistance to its prey.
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leaf hairs influence searching efficiency and predation rate of the predatory mite phytoseiulus persimilis acari phytoseiidae
Experimental and Applied Acarology, 1999Co-Authors: O E Krips, P E L Willems, P W Kleijn, G J Z GolsAbstract:The effect of leaf hairs on searching efficiency of adult female Phytoseiulus persimilis was investigated. For this purpose we used the Ornamental Crop Gerbera jamesonii and determined the predator’s searching efficiency on three cultivars that differ largely in density of leaf hairs on the undersurface of the leaves. Walking speed of the mites was highest on the cultivar with the lowest leaf hair density. Walking activity, defined as the percentage of time spent walking, was not dependent on leaf hair density of the cultivars. At both prey densities tested, time until first predation increased with leaf hair density. Predation rate of adult female P. persimilis is affected by trichome density, especially when prey density is low. At prey densities of 1.3 and 2.5 T. urticae eggs/cm2, predation rate was inversely related to leaf hair density. At a prey density of 8.0 eggs/cm2 no significant effect of leaf hair density on predation rate was found. These negative effects on searching efficiency and predation success at low prey density of P. persimilis suggest that biological control of T urticae on gerbera may be hampered by leaf hairs.
Annette Hohe - One of the best experts on this subject based on the ideXlab platform.
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targeted generation of polyploids in hydrangea maCrophylla through cross based breeding
BMC Genetics, 2020Co-Authors: Conny Trankner, Kristina Gunther, Peter Sahr, Frauke Engel, Annette HoheAbstract:Up to now, diploid and triploid cultivars were reported for the Ornamental Crop Hydrangea maCrophylla. Especially, the origin of triploids and their crossing behaviors are unknown, but the underlying mechanisms are highly relevant for breeding polyploids. By screening a cultivar collection, we identified diploid, triploid, tetraploid and even aneuploid H. maCrophylla varieties. The pollen viability of triploids and tetraploids was comparable to that of diploids. Systematic crosses with these cultivars resulted in viable diploid, triploid, tetraploid and aneuploid offspring. Interestingly, crosses between diploids produced diploid and 0 or 1–94% triploid offspring, depending on the cultivars used as pollen parent. This finding suggests that specific diploids form unreduced pollen, either at low or high frequencies. In contrast, crosses of triploids with diploids or tetraploids produced many viable aneuploids, whose 2C DNA contents ranged between the parental 2C values. As expected, crosses between diploid and tetraploid individuals generated triploid offspring. Putative tetraploid plants were obtained at low frequencies in crosses between diploids and in interploid crosses of triploids with either diploid or tetraploid plants. The analysis of offspring populations indicated the production of 1n = 2x gametes for tetraploid plants, whereas triploids produced obviously reduced, aneuploid gametes with chromosome numbers ranging between haploid and diploid level. While euploid offspring grew normally, aneuploid plants showed mostly an abnormal development and a huge phenotypic variation within offspring populations, most likely due to the variation in chromosome numbers. Subsequent crosses with putative diploid, triploid and aneuploid offspring plants from interploid crosses resulted in viable offspring and germination rates ranging from 21 to 100%. The existence of diploids that form unreduced pollen and of tetraploids allows the targeted breeding of polyploid H. maCrophylla. Different ploidy levels can be addressed by combining the appropriate crossing partners. In contrast to artificial polyploidization, cross-based polyploidization is easy, cheap and results in genetically variable offspring that allows the direct selection of more robust and stress tolerant polyploid varieties. Furthermore, the generation of polyploid H. maCrophylla plants will favor interspecific breeding programs within the genus Hydrangea.
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molecular reconstruction of an old pedigree of diploid and triploid hydrangea maCrophylla genotypes
Frontiers in Plant Science, 2018Co-Authors: Peter Hempel, Annette Hohe, Conny TranknerAbstract:The Ornamental Crop species Hydrangea maCrophylla exhibits diploid and triploid levels of ploidy and develops lacecap (wild type) or mophead inflorescences. In order to characterize a H. maCrophylla germplasm collection, we determined the inflorescence type and the 2C DNA content of 120 plants representing 43 cultivars. We identified 78 putative diploid and 39 putative triploid plants by flow cytometry. In our collection 69 out of 98 flowering plants produced lacecap inflorescences, whereas 29 plants developed mophead inflorescences. Surprisingly, 12 cultivars included diploid as well as triploid plants, while 5 cultivars contained plants with different inflorescence types. We genotyped this germplasm collection using 12 SSR markers that detected 2-7 alleles per marker, and identified 51 different alleles in this collection. We detected 62 distinct fingerprints, revealing a higher genetic variation than the number of cultivars suggested. Only one genotype per cultivar is expected due to the vegetative propagation of Hydrangea cultivars; however we identified 25 cultivars containing 2-4 different genotypes. These different genotypes explained the variation in DNA content and inflorescence type. Diploid and triploid plants with the same cultivar name were exclusively mix-ups. We therefor assume, that 36% of the tested plants were mislabeled. Based on the "Wadenswil" pedigree, which includes 31 of the tested cultivars, we predicted cultivar-specific fingerprints and identified at least 21 out of 31 cultivars by SSR marker-based reconstruction of the "Wadenswil" pedigree. Furthermore, we detected 4 putative interploid crosses between diploid and triploid plants in this pedigree. These interploid crosses resulted in diploid or/and triploid offspring, suggesting that crosses with triploids were successfully applied in breeding of H. maCrophylla.
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Breeding of polyploid heather (Calluna vulgaris)
Euphytica, 2014Co-Authors: Annett Przybyla, Anne Behrend, Christian Bornhake, Annette HoheAbstract:Calluna vulgaris is an important landscaping plant in Northern Europe. As C. vulgaris is the only species within the genus Calluna , the available gene-pool for breeding is rather narrow and phenotypic variation is limited. Hence, a breeding program for polyploids was set up in order to broaden phenotypic variation in this important Ornamental Crop. Therefor basic genetic characteristics of polyploid C. vulgaris were analyzed using the progeny of a spontaneously occurring tetraploid genotype. With the help of morphological and molecular marker analysis, it was determined that the autotetraploid plant probably arose from unreduced gametes resulting from first division restitution. Tetraploids displayed tetrasomic inheritance with free combination of homologous and homeologous chromosomes. Triploids were semi-fertile with a high rate of aneuploids in their progeny. As the so-called bud-blooming flower type is a trait of outstanding interest in breeding of C. vulgaris , a strategy for efficient breeding of triploid bud-bloomers was deduced.
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On the genetics of the 'bud-flowering' trait in the Ornamental Crop Calluna vulgaris
Acta Horticulturae, 2012Co-Authors: Thomas Borchert, Anne Behrend, Annette HoheAbstract:The Ornamental Crop Calluna vulgaris is of increasing importance to the horticultural industry due to a flower organ mutation, the so-called ‘bud-flowering’ phenotype, in which buds remain closed throughout the total flowering period and thereby maintain more colourful flowers for a longer period of time than the wild-type. Moreover, stamens are missing. In order to clarify the genetics of this mutation a comparative study of the wild-type and the 'bud-flowering' flower type of C. vulgaris was initiated. Scanning electron microscopic analyses of flower organs as well as gene expression studies of an AP3-like and a SEP1-like gene in the different flower whorls of both flower types allowed identification of bracts, sepals and petals. However, loss of stamens in the ‘bud-flowering’ phenotype could not be explained by modified spatial expression of known organ identity genes. Therefore, new approaches (map-based cloning and differential transcriptome analysis) are now envisioned in order to elucidate the genetics of the ‘bud-flowering’ phenotype.
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large impact of the apoplast on somatic embryogenesis in cyclamen persicum offers possibilities for improved developmental control in vitro
BMC Plant Biology, 2010Co-Authors: Claudia Hoenemann, Annette Hohe, Sandra Richardt, Katja Kruger, Andreas D Zimmer, Stefan A RensingAbstract:Clonal propagation is highly desired especially for valuable horticultural Crops. The method with the potentially highest multiplication rate is regeneration via somatic embryogenesis. However, this mode of propagation is often hampered by the occurrence of developmental aberrations and non-embryogenic callus. Therefore, the developmental process of somatic embryogenesis was analysed in the Ornamental Crop Cyclamen persicum by expression profiling, comparing different developmental stages of embryogenic cell cultures, zygotic vs. somatic embryos and embryogenic vs. non-embryogenic cell cultures. The analysis was based on a cDNA microarray representing 1,216 transcripts and was exemplarily validated by realtime PCR. For this purpose relative transcript abundances of homologues of a putative receptor kinase, two different glutathione S-transferases (GST), a xyloglucan endotransglycosylase (XET) and a peroxidase (POX) were quantitatively measured by realtime PCR for three different comparisons. In total, 417 genes were found to be differentially expressed. Gene Ontology annotation revealed that transcripts coding for enzymes that are active in the extracellular compartment (apoplast) were significantly overrepresented in several comparisons. The expression profiling results are underpinned by thorough histological analyses of somatic and zygotic embryos. The putative underlying physiological processes are discussed and hypotheses on improvement of the protocol for in vitro somatic embryogenesis in Cyclamen persicum are deduced. A set of physiological markers is proposed for efficient molecular control of the process of somatic embryogenesis in C. persicum. The general suitability of expression profiling for the development and improvement of miCropropagation methods is discussed.
Marcel Dicke - One of the best experts on this subject based on the ideXlab platform.
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the response of phytoseiulus persimilis to spider mite induced volatiles from gerbera influence of starvation and experience
Journal of Chemical Ecology, 1999Co-Authors: O E Krips, P E L Willems, Maarten A. Posthumus, Rieta Gols, Marcel DickeAbstract:When leaves of the Ornamental Crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced.
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compatibility of host plant resistance and biological control of the two spotted spider mite tetranychus urticae in the Ornamental Crop gerbera
Biological Control, 1999Co-Authors: O E Krips, P E L Willems, Marcel DickeAbstract:Abstract We investigated the compatibility of host plant resistance to the spider mite Tetranychus urticae Koch in the Ornamental Crop gerbera with the use of the predatory mite Phytoseiulus persimilis Athias-Henriot for biological control. We used four gerbera cultivars on which the intrinsic rate of population increase (rm) of T. urticae was previously found to differ largely. We performed life-history studies on those cultivars with P. persimilis and determined whether the developmental time, peak oviposition rate, and rm of the predator was influenced by host plant resistance. Because the first egg of P. persimilis is usually a male and therefore does not contribute to the population growth rate, we discarded the first egg of all predators from our analyses. The egg-to-second-egg developmental time of the predator was approximately 5.2 days. This developmental time was slightly but significantly shorter on gerbera cultivar Fame than on the other three cultivars. However, this shorter developmental time did not lead to a higher rm of the predators on this cultivar. No cultivar effect was found on the peak oviposition rate, which varied from 5.1 to 5.4 eggs/female/day. On the cultivars used, the rm of the spider mites was previously found to vary from 0.09 to 0.23 per day. We did not find any effect of spider mite resistance in gerbera on the rm of the predators, which ranged from 0.43 to 0.45 per day. Hence, the capacity for population increase of P. persimilis is not influenced by host plant resistance to its prey.
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intrinsic rate of population increase of the spider mite tetranychus urticae on the Ornamental Crop gerbera intraspecific variation in host plant and herbivore
Entomologia Experimentalis Et Applicata, 1998Co-Authors: O E Krips, P E L Willems, A Witul, Marcel DickeAbstract:Eight cultivars of the Ornamental Crop Gerbera jamesonii Bolus (Asteraceae) were compared in host plant suitability for the two spotted spider mite Tetranychus urticae Koch (Acarina: Tetranychidae). This was done by determining the intrinsic rate of population increase, rm, of spider mites on leaf discs of plants from each of the cultivars. Large differences in rm values were found, ranging from 0.088/day on cultivar Bianca to 0.242/day on cultivar Sirtaki. This variation in rm was mainly caused by differences in developmental time of the spider mites. We assessed the performance of spider mites on young and old leaves of the two gerbera cultivars Bianca and Sirtaki. On Sirtaki the spider mites had a shorter developmental time and higher peak oviposition rate on young leaves than on old leaves. However, on Bianca such an effect was not found. We also determined the performance of two spider mite strains on the resistant gerbera cultivar Bianca. We compared the rm of a strain that had been reared on this cultivar for approximately half a year with the rm of a strain that was reared on bean. The rm of the strain that was reared on cultivar Bianca increased to 0.208/day, which is however still substantially lower than the rm on the susceptible cultivar Sirtaki.
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Comparison of Cultivars of Ornamental Crop Gerbera jamesonii on Production of Spider Mite-Induced Volatiles, and Their Attractiveness to the Predator, Phytoseiulus persimilis
Journal of Chemical Ecology, 2001Co-Authors: O E Krips, P E L Willems, Rieta Gols, M. A. Posthumus, G. Gort, M. DickeAbstract:We investigated whether volatiles produced by spider mite-damaged plants of four gerbera cultivars differ in attractiveness to Phytoseiulus persimilis , a specialist predator of spider mites, and how the mite-induced odor blends differ in chemical composition. The gerbera cultivars differed in resistance, as expressed in terms of spider mite intrinsic rate of population increase ( r _m). In order of increasing resistance these were Sirtaki, Rondena, Fame, and Bianca. To correct for differences in damage inflicted on the cultivars, we developed a method to compare the attractiveness of the blends, based on the assumption that a larger amount of spider mite damage leads to higher attraction of P. persimilis . Spider mite-induced volatiles of cultivars Rondena and Bianca were preferred over those of cultivar Sirtaki. Spider mite-induced volatiles of cultivars Sirtaki and Fame did not differ in attractiveness to P. persimilis . Sirtaki plants had a lower relative production of terpenes than the other three cultivars. This was attributed to a low production of cis -α-bergamotene, trans -α-bergamotene, trans -β-bergamotene, and ( E )-β-farnesene. The emission of ( E )-β-ocimene and linalool was lower in Sirtaki and Fame leaves than in Bianca and Rondena. The importance of these chemical differences in the differential attraction of predatory mites is discussed.
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the response of phytoseiulus persimilis to spider mite induced volatiles from gerbera influence of starvation and experience
Journal of Chemical Ecology, 1999Co-Authors: O E Krips, P E L Willems, Maarten A. Posthumus, Rieta Gols, Marcel DickeAbstract:When leaves of the Ornamental Crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced.
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the response of phytoseiulus persimilis to spider mite induced volatiles from gerbera influence of starvation and experience
Journal of Chemical Ecology, 1999Co-Authors: O E Krips, P E L Willems, Rieta Gols, Maarten A. PosthumusAbstract:When leaves of the Ornamental Crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced. We studied the attraction of P. persimilis to the volatiles from spider mite-damaged gerbera leaves and how attraction is affected by starvation and previous experience. Phytoseiulus persimilis that were reared on spider mites (T. urticae) on Lima bean were not attracted to spider mite-induced volatiles from gerbera. Starvation did not influence the predator's response to these volatiles. In contrast, predators that were reared on spider mites on gerbera leaves were strongly attracted to volatiles from spider mite-infested gerbera. This was found also for predators that originated from a culture on spider mite-infested bean and were offered six days of experience with spider mites on gerbera leaves.