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  • Botany & Plant Biology 2007 - Abstract Search
    Smith James F 2 Novak Stephen J 3 Assessing allozyme diversity and polyploidy in the rare southwestern Idaho endemic Lepidium papilliferum Rare plant species typically exhibit low levels of genetic diversity and high levels of genetic differentiation However habitat destruction and fragmentation can alter historic patterns of gene flow and increase the risk of genetic erosion in such species Several mechanisms may counter the adverse genetic consequences of habitat destruction and fragmentation such as polyploidy or an outcrossing mating system but the role of polyploidy in buffering against genetic erosion has only recently been assessed Lepidium papilliferum is a rare herbaceous plant endemic to sagebrush steppe communities of southwestern Idaho The base haploid chromosome number of Lepidium is n 8 Previous studies have shown that North American species of Lepidium are apparently allopolyploids The purpose of the current study was to determine the chromosome number of L papilliferum and to use enzyme electrophoresis to determine whether enzyme banding patterns are consistent with autopolyploid or allopolyploid gene expression Chromosome counts were conducted on pollen mother cells using the acetocarmine staining technique Haploid chromosome numbers of pollen mother cells among populations of L papilliferum ranged from 15 to 17 n 15 96 0 16 Although not conclusive preliminary observations on chromosome pairing behavior suggest multivalent formation at meiosis Enzyme banding patterns and a gene duplication at TPI were consistent with polyploid gene expression Both balanced and unbalanced heterozygotes were observed at all polymorphic loci except one There was no evidence of fixed heterozygosity for any of the loci but neither did we consistently detect multiple alleles three or more at any locus These data are consistent with the available literature on L papilliferum and indicate that the species is probably an allotetraploid derived from closely related parental species Based on the level

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=1785 (2016-02-01)
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  • Botany & Plant Biology 2007 - Abstract Search
    Biology 2007 Home Login Unable to connect to database 13 21 06 Unable to connect to database 13 21 06 SQL Statement is null or not a SELECT 13 21 06 Abstract Detail Systematics Section ASPT Pfeil Bernard E 1 Bayer Randall J 2 Assessing hybridisation lineage sorting and rapid radiation in Citrus The taxonomy and phylogeny of Citrus has been a challenge probably for the following reasons a 4 000 year history of human cultivation hybridisation and selection especially of somatic mutations unusual reproductive biology such as clonal reproduction via nucellar embryogenesis a fairly recent radiation of the main genetic diversity and the ability to hybridise with related genera This talk will focus on advances in understanding the phylogeny Studies using one or two cpDNA regions found little phylogenetic resolution but with many regions added and clear improvements obtained not all relationships are resolved Therefore rapid radiation is suggested However untangling the effects of lineage sorting from rapid radiation requires further examination Nuclear DNA phylogenies have the power to capture both parental lineages of hybridisation events as well as provide insight into the scope of lineage sorting via coalescence methods Log in to add this item to your schedule

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=1301 (2016-02-01)
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  • Botany & Plant Biology 2007 - Abstract Search
    f Royle Hydrocharitaceae the only species of the monotypic genus Hydrilla is a widely distributed invasive aquatic weed As the range of Hydrilla verticillata commonly hydrilla expands in the United States including the appearance of herbicide resistant populations impacts to aquatic biodiversity and the economy continue to mount Despite hydrilla s notoriety as a noxious weed there is little information regarding the origin of North American plants vectors of spread and the level of genetic diversity that occurs within and between introduced populations We have commenced a research project to evaluate the genetic composition of hydrilla populations from the United States to 1 ascertain the pattern of introduction and spread of populations in the U S 2 infer possible vectors of spread and 3 evaluate genetic potential for herbicide resistance We sampled hydrilla from a number of U S East Coast populations Amplification and sequencing of internal spacer regions ITS 1 and ITS 2 and the 5 8S region of nuclear ribosomal DNA showed seven nucleotide differences that divide the samples into two groups corresponding to the known East Coast distribution of monoecious and dioecious hydrilla types However insufficient variation is present in the ITS sequences to address research questions

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=1759 (2016-02-01)
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  • Botany & Plant Biology 2007 - Abstract Search
    Assessment of Genetic Diversity of Red Oak Species using DNA marker profiling Red oaks of the Cumberland Plateau specifically northern red oak Quercus rubra southern red oak Q falcata scarlet oak Q coccinea black oak Q velutina and shumard s oak Q shumardii are important keystone species in the maintenance of biodiversity The last four species are capable of extensive hybridization with northern red oak as well as with each other oak species Identification of pure species vs hybrids is an important attribute for understanding the population dynamics of oaks and for the economic reasons as well Therefore categorization of genetic diversity within and among the oak species with the use of molecular markers may facilitate unambiguous identification of trees The objective of this study was to establish a panel of microsatellite markers SSRs for screening red oak populations of the Southern Cumberland Plateau We examined the cross species amplification of 30 SSRs developed based on northern red oak genome in other members of the family Fagaceae We isolated DNA from cambial tissue of three trees each of northern red oak southern red oak scarlet oak black oak and shumard s oak A majority of the SSRs exhibited cross species

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=445 (2016-02-01)
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  • Botany & Plant Biology 2007 - Abstract Search
    signaling research is that it is difficult to obtain consistent high expression of transgenes of interest in Arabidopsis guard cells using known guard cell promoters or the constitutive 35S cauliflower mosaic virus promoter An additional drawback of the 35S promoter is that constitutively expressing a gene could cause pleiotropic effects To improve the targeted expression of genes in guard cells we isolated strong guard cell promoter candidates Among the promoters we analyzed one promoter drives very strong guard cell reporter gene expression including GUS beta glucuronidase and yellow cameleon GFP based calcium FRET reporter The expression of yellow cameleon was sufficiently strong to resolve repetitive calcium transients in guard cells of intact plants Besides guard cells in leaves the reporter gene is also expressed in guard cells in leaf petioles floral stems sepals and carpels Reporter gene expression is weaker in immature guard cells and also in aged plant tissues The expression may not be entirely specific to guard cells as we sometimes observed apparent reporter expression in epidermal cells at lower levels To further analyze the relative promoter specificity to guard cell we transformed the reporter construct into guard cell development mutants including too many mouths tmm 1 and

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=665 (2016-02-01)
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  • Botany & Plant Biology 2007 - Abstract Search
    biotech Risk Assessment Kwak Man Sup 1 Shin Jeong Sheop 1 Paek Kyung Hee 1 Bae Jung Myung 2 A Strong Constitutive Gene Expression System Derived from ibAGP1 Promoter and Its Transit Peptide To develop a strong constitutive gene expression system the activities of ibAGP1 promoter and its transit peptide were investigated using transgenic Arabidopsis and a GUS reporter gene The ibAGP1 promoter directed GUS expression in almost entire tissues including rosette leaf inflorescence stem inflorescence cauline leaf and root suggesting that the ibAGP1 promoter is a constitutive promoter GUS expression mediated by ibAGP1 promoter was weaker than that by CaMV35S promoter in all tissue types but when GUS protein was targeted to plastids with the aid of the ibAGP1 transit peptide GUS levels increased to higher levels in lamina petiole and cauline leaf compared to those produced by CaMV35S promoter The enhancing effect of ibAGP1 transit peptide on the accumulation of foreign protein was tissue specific accumulation was high in lamina and inflorescence but low in root and primary inflorescence stem The transit peptide effect in the leaves was maintained highly regardless of developmental stages of plants The ibAGP1 promoter and its transit peptide also directed strong GUS gene

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=1577 (2016-02-01)
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  • Botany & Plant Biology 2007 - Abstract Search
    2 Crk Tanja 2 Wroblewski Tadeusz 3 Michelmore Richard 4 Greenberg Jean T 2 A Study of Interactions Between Pseudomonas syringae Effectors and Lettuce The plant pathogen Pseudomonas syringae injects proteins known as effectors into the plant cells using a type III secretion system to better enable infection These effectors aid in bacterial pathogenesis but sometimes are recognized by the host plant and elicit a hypersensitive response a form of programmed cell death that serves to restrict the growth of the pathogen The roles of most effectors are only known in the context of a few host plants Our goal is to expand the information on the role of effectors in the infection process and host range restriction on different crop species Here we focused on the role of several effectors in lettuce infections We have used the ability of an effector to induce cell death on lettuce as a possible indication that the effector is recognized by a particular cultivar Several P syringae effectors can induce cell death on one or more cultivars of lettuce Mariska Valmaine and Ninja when introduced via Agrobacterium tumefaciens To test the role of these effectors in host range restriction and or virulence we created transgenic P syringae strains of a disease causing isolate P syrinage pv alisalensis BS228 expressing cell death effectors cloned from other P syringae strains Inoculation of these strains into lettuce revealed that AvrRpt2 can dramatically restrict the growth and symptoms of BS228 on all lettuce cultivars tested whereas AvrB and AvrRps4 did not significantly alter the disease caused by BS228 compared to inoculations with strains carrying a control vector Liquid growth curves confirmed that the transgenic bacteria grow at approximately the same rate in vitro as wildtype These results indicate that lettuce can recognize AvrRpt2 Other cell death effectors

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=2106 (2016-02-01)
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  • Botany & Plant Biology 2007 - Abstract Search
    N 2 Smith Laurie G 3 Asymmetric cell division in maize stomata Asymmetric cell division is a critical component of numerous processes in plant development In maize asymmetric divisions involving polarization of the mother cell before division are vital for the formation of the stomata The maize stomata is a complex comprising four cells a central guard cell pair flanked by two subsidiary cells During the development of the stomata two subsidiary mother cells SMCs are recruited into the complex by the guard mother cell GMC and subsequently divide asymmetrically to each produce a subsidiary cell and an unspecialized pavement cell A mutator screen has been carried out to identify genes which participate in epidermal cell patterning in the maize leaf and a gene designated pangloss1 pan1 appearing to play a role in SMC division has been identified Characterization of the pan1 mutant phenotype has revealed altered actin localization and depolarization of the nucleus in the SMC leading to subsidiary cell defects The pan1 gene has been cloned and encodes a putative leucine rich repeat receptor like kinase LRR RLK LRR RLKs comprise the largest class of plant receptor kinases and are known to regulate a wide variety of processes

    Original URL path: http://2007.botanyconference.org/engine/search/index.php?func=detail&aid=1819 (2016-02-01)
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