Oviposition by the Banded Sunflower Moth, \u3ci\u3eCochylis Hospes\u3c/i\u3e (Lepidoptera: Cochylidae) in Response to \u3ci\u3eHelianthus Annuus\u3c/i\u3e Pollen

Oviposition on an artificial substrate by the banded sunflower moth Cochylis hospes Walsingham was examined in response to sunflower pollen (Helianthus annuus) and sunflower pollen extract. Sunflower pollen in quantities as small as 0.2 mg significantly reduced oviposition on an artificial substrate relative to a control without pollen. Aqueous pollen extract applied to the artificial substrate significantly reduced oviposition with respect to the control substrate that was treated with solvent. Banded sunflower moths have gained some reproductive or competitive advantage by ovipositing on the bracts of sunflower and a deterrent effect of pollen could, at least in part, have had functional significance in the development of a behavioral preference for the bracts of the sunflower head as an oviposition site

A Tobacco Homolog of DCN1 is Involved in Cellular Reprogramming and in Developmental Transitions

Plant proteomes show remarkable plasticity in reaction to environmental challenges and during developmental transitions. Some of this adaptability comes from ubiquitin-mediated protein destruction regulated by cullin-RING E3 ubiquitin ligases (CRLs). CRLs are activated through modification of the cullin subunit with the ubiquitin-like protein RUB/NEDD8 by an E3 ligase called defective in cullin neddylation 1 (DCN1). Here we show that tobacco DCN1 binds ubiquitin and RUB/NEDD8, and associates with cullin. When knocked down by RNAi, tobacco pollen formation stopped and zygotic embryogenesis was blocked around the globular stage. Additionally, we found that RNAi of DCN1 inhibited the stress-triggered reprogramming of cultured microspores from their intrinsic gametophytic mode of development to an embryogenic state. This stress-induced developmental switch is a known feature in many important crops and leads ultimately to the formation of haploid embryos and plants. Compensating the RNAi effect by re-transformation with a promoter-silencing construct restored pollen development and zygotic embryogenesis, as well as the ability for stress-induced formation of embryogenic microspores. Overexpression of DCN1, however, accelerated pollen tube growth and increased the potential for microspore reprogramming. These results demonstrate that the biochemical function of DCN1 is conserved in plants and that its activity is specifically required for transitions during pollen development and embryogenesis, and for pollen tube tip growth

Callose (β-1,3 glucan) is essential for Arabidopsis pollen wall patterning, but not tube growth

Background: Callose (β-1,3 glucan) separates developing pollen grains, preventing their underlying walls (exine) from fusing. The pollen tubes that transport sperm to female gametes also contain callose, both in their walls as well as in the plugs that segment growing tubes. Mutations in CalS5, one of several Arabidopsis β-1,3 glucan synthases, were previously shown to disrupt callose formation around developing microspores, causing aberrations in exine patterning, degeneration of developing microspores, and pollen sterility. Results: Here, we describe three additional cals5 alleles that similarly alter exine patterns, but instead produce fertile pollen. Moreover, one of these alleles (cals5-3) resulted in the formation of pollen tubes that lacked callose walls and plugs. In self-pollinated plants, these tubes led to successful fertilization, but they were at a slight disadvantage when competing with wild type. Conclusion: Contrary to a previous report, these results demonstrate that a structured exine layer is not required for pollen development, viability or fertility. In addition, despite the presence of callose-enriched walls and callose plugs in pollen tubes, the results presented here indicate that callose is not required for pollen tube functions

Abundance of Insects Inhabiting the Male Strobili of Red Pine

(excerpt) Southwood (1973) concluded that pollen feeding was probably the first step in the development of the phytophagous habit in insects, because pollen, compared with plant foliage, is rich in nutrients and low in sewndary defense substances. Surprisingly, little is known about insects that feed mainly on pollen. For example, in a bibliography of insects that feed on reproductive structures of North American conifers (Barcia and Merkel, 1972), less than three per cent of 719 references pertained to pollen feeders. This note reports on the kinds and abundance of insects found inhabiting clusters of fresh staminate or male strobili (MS) of 60- to 65-year-old red pine trees in two seed production areas (SPAs) in northern Minnesota

Effects of Alternaria alternata f.sp. lycopersici toxins on pollen

Effects of the phytotoxic compounds (AAL-toxins) isolated from cell-free culture filtrates of Alternaria alternata f.sp. lycopersici on in vitro pollen development were studied. AAL-toxins inhibited both germination and tube growth of pollen from several Lycopersicon genotypes. Pollen from susceptible genotypes, however, was more sensitive for AAL-toxins than pollen from resistant plants, while pollen of species not belonging to the host range of the fungus was not significantly affected by the tested toxin concentrations. AAL-toxins elicit symptoms in detached leaf bioassays indistinguishable from those observed on leaves of fungal infected tomato plants, and toxins play a major role in the pathogenesis. Apparently, pathogenesis-related processes and mechanisms involved in disease resistance are expressed in both vegetative and generative tissues. This overlap in gene expression between the sporophytic and gametophytic level of a plant may be advantageously utilized in plant breeding programmes. Pollen may be used to distinguish susceptible and resistant plants and to select for resistances and tolerances against phytotoxins and other selective agents.

Proline synthesis in developing microspores is required for pollen development and fertility

Background: In many plants, the amino acid proline is strongly accumulated in pollen and disruption of proline synthesis caused abortion of microspore development in Arabidopsis. So far, it was unclear whether local biosynthesis or transport of proline determines the success of fertile pollen development. Results: We analyzed the expression pattern of the proline biosynthetic genes PYRROLINE-5-CARBOXYLATE SYNTHETASE 1 & 2 (P5CS1 & 2) in Arabidopsis anthers and both isoforms were strongly expressed in developing microspores and pollen grains but only inconsistently in surrounding sporophytic tissues. We introduced in a p5cs1/p5cs1 p5cs2/P5CS2 mutant background an additional copy of P5CS2 under the control of the Cauliflower Mosaic Virus (CaMV) 35S promoter, the tapetum-specific LIPID TRANSFER PROTEIN 12 (Ltp12) promoter or the pollen-specific At5g17340 promoter to determine in which site proline biosynthesis can restore the fertility of proline-deficient microspores. The specificity of these promoters was confirmed by β-glucuronidase (GUS) analysis, and by direct proline measurement in pollen grains and stage-9/10 anthers. Expression of P5CS2 under control of the At5g17340 promoter fully rescued proline content and normal morphology and fertility of mutant pollen. In contrast, expression of P5CS2 driven by either the Ltp12 or CaMV35S promoter caused only partial restoration of pollen development with little effect on pollen fertility. Conclusions: Overall, our results indicate that proline transport is not able to fulfill the demand of the cells of the male germ line. Pollen development and fertility depend on local proline biosynthesis during late stages of microspore development and in mature pollen grains

Toward in vitro fertilization in Brachiaria spp.

Brachiaria are forage grasses widely cultivated in tropical areas. In vitro pollination was applied to accessions of Brachiaria spp. by placing pollen of non-dehiscent anthers on a solid medium near isolated ovaries. Viability and in vitro germination were tested in order to establish good conditions for pollen development. Comparing sexual to apomictic plants, apomictic pollen has more abortion after meiosis during the microspore stage and a lower viability and, of both types, only some plants have sufficient germination in a high sugar concentration. Using in vitro pollination with the sexual plant, the pollen tube penetrates into the nucellus and micropyle, but the embryo sac degenerates and collapses. In the apomictic B. decumbens, in vitro pollination leads to the transfer of the sperm nuclei into the egg cell and the central cell. The results are discussed according to normal fertilization and barriers in sexual and apomictic plants

Exploration of Limonium interspecific breeding possibility : a thesis presented in partial fulfilment of the requirement for the degree of Master of Science in Plant Science at Massey University, Palmerston North, New Zealand

Interspecific crossability was investigated in the genus Limonium (Plumbaginaceae). Six Limonium species were chosen for this study, five of which are dimorphic and L.perigrinum which is monomorphic. Ovary, ovule and embryo development was investigated, as were in vitro pollen germination and pollen tube growth. Unilateral incompatibility was observed in 8 interspecific combinations. A high frequency of interspecific crossability was observed between L.perezii X L.sinuatum and L.sinense X L.aureum. Pollen tubes were frequently observed penetrating the ovules in these crosses. Pollen tube growth that terminated in the styles or was restricted to the stigmas was found in some Limonium interspecific crosses. Abnormalities of pollen tube growth in the interspecific crosses included heavy callose deposits at the tips of pollen tubes; pollen tube branching and pollen tube growing in the wrong direction. Embryo, ovule and ovary development was studied with L.perezii plants following conspecific pollination. Three distinct groupings of florets can be recognised at the basis of their post-pollination growth and development. Twenty-six percent of conspecific pollinated florets showed no ovary and ovule growth. No embryo was found in this group. In eleven percent of florets, ovaries and ovules grew up to Day 12 after pollination and then shrivelled. No embryo was ever found in this group. Sixty-three percent florets produced embryos following conspecific pollination and developed normally. The viability of Limonium pollen was assessed with Alexander's stain and fluorochromatic reaction (FCR) stain. Optimal conditions for in vitro L.perezii pollen germination and tube growth were established. Poly-ethylene glycol and filter paper supports were of particular significance. In vitro pollen germination rate of about 40% was achieved. Plant growth regulators (IAA, GA 3 and ethylene), some minerals (manganese sulphate, copper sulphate) and prehydration treatment were used in experiments to improve pollen germination and tube growth. None of these factors, however, had positive effect on either pollen germination or tube growth. It was found that while L.perezii pollen tube growth tolerates a wide range of temperature, there is an optimum between 20°C-25°C

Detection and Quantification of Grass and Olea Airborne Pollen Allergens in Outdoor Air Samples and its Correlation with Pollen Counts

Detection and Quantification of Grass and Olea Airborne Pollen Allergens in Outdoor Air Samples and its Correlation with Pollen Counts R Ferro1*, R Ribeiro1*, MR Martins1,2, AT Caldeira1,3, E Caeiro6, CM Antunes1,5 & R Brandão2,4 and the HIALINE working group7 1Dep. of Chemistry, University of Evora, Portugal; 2Mediterranean Inst. Crop and Environment Sciences, Univ.Evora, Portugal; 3Centro Química, University of Évora, Portugal; 4Dep. Biology, University of Evora; 5Center for NeuroSciences and Cell Biology-University of Coimbra, Portugal; 6Soc.Portuguesa Alergol.Imunologia Clínica , Portugal 7 M. Thibaudon, France, M. Smith, United Kingdom, C. Galan, Spain R. Albertini, Italy, L. Grewling, Poland, G. Reese, Germany, A. Rantio-Lehtimäki, Finland, S. Jäger and U. Berger, Austria, M. Sofiev, Finland, I. Sauliene, Lithuania, L. Cecchi, Italy Presenting author: [email protected] tel: +351 266760889 Introduction: Allergic respiratory diseases broken out after an exposure to airborne pollen, as asthma and allergic rhinitis, are deeply increasing and they represent one of the major public health problems nowadays, affecting about 40% of European population. In Portugal, grass and Olea europaea pollen are certainly one of the main sources of athmospheric aeroallergens and as such, one of the main causes of respiratory allergy. For these reasons, it is useful the development of new strategies for prevention and treatment of these pathologies. The execution of aerobiological analysis including pollen calendars and/or immunoassays for the detection and quantification of allergens which could forecast the allergenic potential of the athmosphere are quite relevant since they would contribute to develop prevention measures of allergic respiratory diseases. The aim of this study was to evaluate the putative correlation between the concentration of some of the major allergens of and with their pollen counts. Methodology: On a meteorological platform at the town center of Evora (south Portugal), ambient air was sampled at 800L/min with a Chemvol high-volume cascade impactor equipped with stages PM>10µm, 10 µm>PM>2.5µm. The polyurethane impacting substrate was extracted with 0.1M NH4HCO3, pH8.1, supplemented with 0.1% BSA. The major pollen allergens from grass Phleum p 5 and olive Ole e 1 were determined with allergen specific ELISA´s. Airborne pollen of and Olea europaea simultaneously monitored with a Burkard Seven Day Recording Volumetric Spore Trap* , between the 30th of April and the 8th of July of 2009. Both samplers were placed side-by-side with air input at the same level. Results: During the pollen season of 2009, high values of grass pollen were recorded between May 2th and June 1 th. It was also observed that the air content of Phl p5 or Ole e1 aeroallergens were directly correlated with airborne pollen counts of Poaceae and Oleaceae, respectively. Conclusions: These results suggest that the directly quantification of aeroallergens may contribute, together with pollen counts of air samples, to define the allergic risk with higher precision. Acknowledgments: This study is integrated in the european project HIALINE (Executive Agency for Health and Consumers under grant agreement No 2008 11 07

Moisture source and diet affect development and reproduction of Orius thripoborus and Orius naivashae, two predatory anthocorids from southern Africa

The effect of moisture source and diet on the development and reproduction of the pirate bugs, Orius thripoborus (Hesse) and Orius naivashae (Poppius) (Hemiptera: Anthocoridae) was examined in the laboratory. Both species had been collected in and around sugarcane fields in South Africa. Supplementing eggs of the flour moth Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) with a green bean pod as a moisture source yielded better nymphal survival and faster development, as compared with free water encapsulated in Parafilm, suggesting that the predators may extract extra nutrients from the bean pod. The impact of two factitious foods and moist honey bee pollen on developmental and reproductive parameters of both predators was also investigated. The overall performance of both Orius species on E. kuehniella eggs and cysts of brine shrimp, Artemia franciscana Kellogg (Crustacea: Artemiidae) was better than on pollen. Nonetheless, a pollen diet alone allowed 66 and 78% of the nymphs of O. thripoborus and O. naivashae, respectively, to reach adulthood. Overall, developmental and reproductive performance of O. thripoborus on the tested diets was superior to that of O. naivashae. The implications of these findings for the mass production of these predators and their potential role in biological control programs in southern Africa are discussed