Life Sciences Commons^™

Aintegumenta And Aintegumenta-Like6 Regulate Auxin-Mediated Flower Development In Arabidopsis, Beth A. Krizek

Faculty Publications

Background: Two related genes encoding AP2/ERF-type transcription factors, AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6 (AIL6), are important regulators of floral growth and patterning in Arabidopsis. Evidence suggests that these genes promote several aspects of flower development in response to auxin. To investigate the interplay of ANT, AIL6 and auxin during floral development, I have examined the phenotypic consequences of disrupting polar auxin transport in ant, ail6 and ant ail6 mutants by either genetic or chemical means.

Results: Plants containing mutations in ANT or AIL6 alone or in both genes together exhibit increased sensitivity to disruptions in polar auxin transport. …

Aintegumenta And Aintegumenta-Like6 Act Redundantly To Regulate Arabidopsis Floral Growth And Patterning, Beth A. Krizek

Faculty Publications

An Arabidopsis (Arabidopsis thaliana) flower consists of four types of organs arranged in a stereotypical pattern. This complex floral structure is elaborated from a small number of floral meristem cells partitioned from the shoot apical meristem during reproductive development. The positioning of floral primordia within the periphery of the shoot apical meristem depends on transport of the phytohormone auxin with floral anlagen arising at sites of auxin maxima. An early marker of lateral organ fate is the AP2/ERF-type transcription factor AINTEGUMENTA (ANT), which has been proposed to act downstream of auxin in organogenic growth. Here, I show that …

Development Of New Simple Sequence Repeat Markers For Pearl Millet, O. P. Yadav, S. E. Mitchell, A. Zamora, Theresa M. Fulton, Stephen Kresovich

Faculty Publications

No abstract provided.

Aintegumenta Contributes To Organ Polarity And Regulates Growth Of Lateral Organs In Combination With Yabby Genes, Staci Nole-Wilson, Beth A. Krizek

Faculty Publications

Lateral organs in flowering plants display polarity along their adaxial-abaxial axis with distinct cell types forming at different positions along this axis. Members of three classes of transcription factors in Arabidopsis (Arabidopsis thaliana; the Class III homeodomain/leucine zipper [HD-ZIP] proteins, KANADI proteins, and YABBY proteins) are expressed in either the adaxial or abaxial domain of organ primordia where they confer these respective identities. Little is known about the factors that act upstream of these polarity-determining genes to regulate their expression. We have investigated the relationship between AINTEGUMENTA (ANT), a gene that promotes initiation and growth of lateral …

Toward Sequencing The Sorghum Genome: A U.S. National Science Foundation-Sponsored Workshop Report, Stephen Kresovich, Brad Barbazuk, Joseph A. Bedell, Andrew Borrell, C. Robin Buell, John Burke, Sandra Clifton, Marie-Michéle Cordonnier-Ptratt, Stan Cox, Jeff Dahlberg, John Erpelding, Theresa M. Fulton, Bob Fulton, Lucinda Fulton, Alan R. Gingle, C. Tom Hash, Yinghua Huang, David Jordan, Patricia E. Klein, Robert R. Klein, Jurandir Magalhaes, Richard Mccombie, Paul Moore, John E. Mullet, Peggy Ozias-Akins, Andrew H. Paterson, Kay Porter, Lee Pratt, Bruce Roe, William Rooney, Patrick S. Schnable, David M. Stelly, Mitchell Tuinstra, Doreen Ware, Ujwala Warek

Faculty Publications

Members of the worldwide sorghum (Sorghum spp.) community, including private sector and international scientists as well as community representatives from closely related crops such as sugarcane (Saccharum spp.) and maize (Zea mays), met in St. Louis, Missouri, on November 9, 2004, to lay the groundwork for future advances in sorghum genomics and, in particular, to coordinate plans for sequencing of the sorghum genome. Key developments that made this workshop timely included advances in knowledge of the sorghum genome that provide for the development of a genetically anchored physical map to guide sequence assembly and annotation, the …

Genetic Diversity Of Peanut (Arachis Hypogaea L.) And Its Wild Relatives Based On The Analysis Of Hypervariable Regions Of The Genome, Marcio De Carvalho Moretzsohn, Mark S. Hopkins, Sharon E. Mitchell, Stephen Kresovich, Jose Francisco Montenegro Valls, Marcio Elias Ferreira

Faculty Publications

Background: The genus Arachis is native to a region that includes Central Brazil and neighboring countries. Little is known about the genetic variability of the Brazilian cultivated peanut (Arachis hypogaea, genome AABB) germplasm collection at the DNA level. The understanding of the genetic diversity of cultivated and wild species of peanut (Arachis spp.) is essential to develop strategies of collection, conservation and use of the germplasm in variety development. The identity of the ancestor progenitor species of cultivated peanut has also been of great interest. Several species have been suggested as putative AA and BB genome donors …

Aintegumenta Utilizes A Mode Of Dna Recognition Distinct From That Used By Proteins Containing A Single Ap2 Domain, Beth A. Krizek

Faculty Publications

The Arabidopsis protein AINTEGUMENTA (ANT) is an important regulator of organ growth during flower development. ANT is a member of the AP2 subclass of the AP2/ERF family of plant-specific transcription factors. These proteins contain either one or two copies of a DNA-binding domain called the AP2 domain. Here, it is shown that ANT can act as a transcriptional activator in yeast through binding to a consensus ANT-binding site. This activity was used as the basis for a genetic screen to identify amino acids that are critical for the DNA binding ability of ANT. Mutants that showed reduced or no activation …

Molecular Diversity, Structure And Domestication Of Grasses, Edward S. Buckler Iv, Jeffry M. Thornsberry, Stephen Kresovich

Faculty Publications

Over the last 10,000 years, crop domestication has been the single most important human cultural development. Grasses are prominent among these crops, and provide the vast majority of the world's food. Similar traits have been selected during the domestication and breeding of these critically important grasses, and since they share a similar complement of genes, the same set of genes may have been selected. Even though the process of domestication occurred over the same 5000 to 10,000 year period, the domesticated grasses have major differences in genome structure, diversity, and life history. Molecular investigations of grass domestication have succeeded in …

Dna Binding Properties Of The Arabidopsis Floral Development Protein Aintegumenta, Staci Nole-Wilson, Beth A. Krizek

Faculty Publications

The Arabidopsis protein AINTEGUMENTA (ANT) is a member of a plant-specific family of transcription factors (AP2/EREBP) that share either one or two copies of an approximately 70 amino acid region called the AP2 repeat. DNA binding activity has been demonstrated previously for members of this family containing a single AP2 repeat. Using an in vitro selection procedure, the DNA binding specificity of the two AP2 repeat containing protein ANT was found to be 5'-gCAC(A/G)N(A/T)TcCC(a/g)ANG(c/t)-3'. This consensus site is much longer than sites recognized by proteins containing a single AP2 repeat and neither AP2 repeat of ANT was alone capable of …

Regulation Of Sup Expression Identifies Multiple Regulators Involved In Arabidopsis Floral Meristem Development, Hajime Sakai, Beth A. Krizek, Steven E. Jacobsen, Elliot M. Meyerowitz

Faculty Publications

During the course of flower development, floral homeotic genes are expressed in defined concentric regions of floral meristems called whorls. The SUPERMAN ( SUP, also called FLO10 ) gene, which encodes a C2H2-type zinc finger protein, is involved in maintenance of the stamen/carpel whorl boundary (the boundary between whorl 3 and whorl 4) in Arabidopsis. Here, we show that the regulation of SUP expression in floral meristems is complex, consisting of two distinct phases, initiation and maintenance. The floral meristem identity gene LEAFY ( LFY ) plays a role in the initiation phase through at least two pathways, which …

Aintegumenta Promotes Petal Identity And Acts As A Negative Regulator Of Agamous, Beth A. Krizek, Valerie Prost, Anthony Macias

Faculty Publications

The Arabidopsis AINTEGUMENTA (ANT) gene has been shown previously to be involved in ovule development and in the initiation and growth of floral organs. Here, we show that ANT acts in additional processes during flower development, including repression of AGAMOUS (AG) in second whorl cells, promotion of petal epidermal cell identity, and gynoecium development. Analyses of ap2-1 ant-6 double mutants reveal that ANT acts redundantly with AP2 to repress AG in second whorl cells. The abaxial surface of ant petals contains features such as stomata and elongated, interdigitated cells that are not present on wild-type petals. …

An Est-Enriched Comparative Map Of Brassica Oleracea And Arabidopsis Thaliana, Tien-Hung Lan, Terrye A. Delmonte, Kim P. Reischmann, Joel Hyman, Stanley P. Kowalski, Jim Mcferson, Stephen Kresovich, Andrew H. Paterson

Faculty Publications

A detailed comparative map of Brassica oleracea and Arabidopsis thaliana has been established based largely on mapping of Arabidopsis ESTs in two Arabidopsis and four Brassica populations. Based on conservative criteria for inferring synteny, “one to one correspondence” between Brassica and Arabidopsis chromosomes accounted for 57% of comparative loci. Based on 186 corresponding loci detected in B. oleracea and A. thaliana, at least 19 chromosome structural rearrangements differentiate B. oleracea and A. thaliana orthologs. Chromosomal duplication in the B. oleracea genome was strongly suggested by parallel arrangements of duplicated loci on different chromosomes, which accounted for 41% of loci …

Differential Expression Of The Arabidopsis Nia1 And Nia2 Genes: Cytokinin-Induced Nitrate Reductase Activity Is Correlated With Increased Nia1 Transcription And Mrna Levels, Xiaodan Yu, Sujatha Sukumaran, László Márton

Faculty Publications

Nitrate reductase (NR) activity increased up to 14-fold in response to treatment of Arabidopsis thaliana seedlings with the cytokinin benzyladenine. NR induction was observed in seedlings germinated directly on cytokinin-containing medium, seedlings transferred to cytokinin medium, and seedlings grown in soil in which cytokinin was applied directly to the leaves. About the same level of induction was seen in both wild-type and Nia2-deletion mutants, indicating that increased NR activity is related to the expression of the minor NR gene, Nia1. The steady-state Nia1 mRNA level was increased severalfold in both wild-type and mutant seedlings after benzyladenine treatment. Transcript …

Antisense Expression Of The Peptide Transport Gene Atptr2-B Delays Flowering And Arrests Seed Development In Transgenic Arabidopsis Plants, Wei Song, Serry Koh, Mihály Czakó, László Márton, Eliana Drenkard, Jeffrey M. Becker, Gary Stacey

Faculty Publications

Previously, we identified a peptide transport gene, AtPTRZ-B, from Arabidopsis thaliana that was constitutively expressed in all plant organs, suggesting an important physiological role in plant growth and development. To evaluate the function of this transporter, transgenic Arabidopsis plants were constructed expressing antisense or sense AtPTRZ-B. Genomic Southern analysis indicated that four independent antisense and three independent sense AtPTRZ-B transgenic lines were obtained, which was confirmed by analysis of the segregation of the kanamycin resistance gene carried on the T-DNA. RNA blot data showed that the endogenous AtPJRZ-B mRNA levels were significantly reduced in transgenic leaves and …

The Arabidopsis Homeotic Genes Apetala3 And Pistillata Are Sufficient To Provide The B Class Organ Identity Function, Beth A. Krizek, Elliot M. Meyerowitz

Faculty Publications

The class B organ identity genes, APETALA3 and PISTILLATA, are required to specify petal and stamen identity in the Arabidopsis flower. We show here that the activities of these two genes are sufficient to specify petals and stamens in flowers, in combination with the class A and C genes, respectively. Flowers of plants constitutively expressing both PISTILLATA and APETALA3 under the control of the 35S promoter from cauliflower mosaic virus consist of two outer whorls of petals and inner whorls of stamens. These plants also exhibit vegetative phenotypes that are not present in either of the singly (APETALA3 …

The Herpes Simplex Virus Thymidine Kinase Gene As A Conditional Negative-Selection Marker Gene In Arabidopsis Thaliana, Mihály Czakó, László Márton

Faculty Publications

The human herpes simplex virus thymidine kinase type 1 gene (HSVtk) acts as a conditional lethal marker in mammalian cells. The HSVtk-encoded enzyme is able to phosphorylate certain nucleoside analogs (e.g. ganciclovir, an antiherpetic drug), thus converting them to toxic DNA replication inhibitors. The utility of HSVtk as a conditional negative-selection marker was explored in Arabidopsis thaliana (L.) Heynh. HSVtk was introduced into Arabidopsis by Agrobaderium-mediated transformation. Transgenic plants were morphologically indistinguishable from wild type and exhibited normal fertility. Canciclovir at lO^-5to 10^-4 M drastically reduced shoot regeneration on transgenic, HSVtk* root explants …

Nuclear Dna Content Variation Within The Rosaceae, E. E. Dickson, K. Arumuganathan, Stephen Kresovich, J. J. Doyle

Faculty Publications

Nuclear DNA content has been estimated using flow cytometry for 17 species and eight cultivars of Malus and for 44 species of 29 other genera within the Rosaceae. Compared to other angiosperms, diploid genome sizes vary little within the family Rosaceae and within the genus Malus. C-values of genera within the subfamilies Spiraeoideae and Rosoideae are among the smallest of flowering plants thus far reported. In general, the Maloideae have the largest diploid genomes of the family, consistent with their higher chromosome numbers and presumed polyploid origin.

Organ-Specific And Development Regulation Of The Nopaline Synthase Promoter In Transgenic Tobacco Plants, Gynheung An, Michael A. Costa, Amitava Mitra, Sam-Bong Ha, László Márton

Faculty Publications

Control regions of the nopaline synthase (nos) gene have been widely used to express foreign genes in plants since the promoter is active in a wide variety of plant tissues. We report here the characteristics of the nos promoter activity in transgenic tobacco (Nicotiana tabacum) plants at various developmental stages. The promoter was highly active in the lower parts of a plant and gradually decreased in the upper parts. This vertical gradient was maintained throughout plant growth until the flowering stage when the overall promoter strength decreased significantly in the vegetative organs. However, in various flower …

Sequence Of The Psba Gene From Wild Type Triazin-Resistant Nicotiana Plumbaginifolia, Anikó Páy, Marvin A. Smith, Ferenc Nagy, László Márton

Faculty Publications

No abstract provided.

The Effect Of Salt Concentration On Auxin Stability In Culture Media, James R. Dunlap, Stephen Kresovich, Robert E. Mcgee

Faculty Publications

The concentrations of indole-3-acetic acid (IAA), naphthaleneacetic acid (NAA) and 2,4-dichlorophenoxyacetic acid (2,4-D) were followed for 35 days in cell-free liquid medium containing 100, 50, or 0% Murashige-Skoog (MS) salt base. Although the concentrations of NAA or 2,4-D remained constant the level of IAA decreased to only 11% of the original concentration after 35 days in the presence of 100% MS salt base. The observed rate of IAA degradation was accelerated by the presence of MS salts.

Clonal Selection Of Sugar Cane For Texas And Louisiana From A Common Germplasm Pool, Stephen Kresovich, Richard D. Breaux

Faculty Publications

The sugar cane (a complex hybrid of Saccharum spp.) cultivar improvement program for the irrigated Lower Rio Grande Valley of Texas, initiated in 1961, has expanded greatly over the past 20 years. Initially, only 8 to 12 cultivars, selected from those previously released from commercial production in Louisiana or Florida, were screened annually for their production potential in the Lower Rio Grande Valley. The current introduction and screening program is more comprehensive utilizing 1) all clones advanced from the first to the second line trials at the U. S. Sugarcane Laboratory at Houma, Louisiana; 2) the advanced "CP" assignments from …