Ploidy Variations in Floridone-Susceptible and -Resistant Hydrilla (Hydrilla verticillata) Biotypes

Weed Science ◽  
2007 ◽  
Vol 55 (6) ◽  
pp. 578-583 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
William T. Haller
Keyword(s):  
Nuclear Dna ◽  
Flow Cytometric Analysis ◽  
Nuclear Dna Content ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Day Length ◽  
Aquatic Weed ◽  
Ploidy Levels ◽  
Systemic Control ◽  
Dna Contents

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Fluridone-susceptible (S) and several fluridone-resistant (R1 to R5) hydrilla biotypes varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions. To correlate varying levels of fluridone resistance to ploidy in hydrilla, flow cytometric analysis was performed. Differential ploidy levels (diploid, 2n = 2x = 16; triploid, 2n = 3x = 24; and tetraploid, 2n = 4x = 32) were reported among different hydrilla biotypes, plants within each biotype, and within shoot tissues of the same plant. Triploid plants were predominant in all biotypes. Diploid plants were observed in all hydrilla biotypes except the susceptible hydrilla (S). Plants with tetraploidy were rare within biotypes. The diploid, triploid, and tetraploid plants had nuclear DNA contents of 2.43 to 2.73 pg, 3.44 to 3.71 pg, and 4.64 to 4.90 pg, respectively, and no differences were observed among plants with same ploidy for nuclear DNA content in different hydrilla biotypes. Endoreduplication patterns were observed in diploid plants of R1 and R3 biotypes. However, no plant with higher ploidy levels (triploid or tetraploid) in any hydrilla biotypes showed endoreduplication.

Mutations in Phytoene Desaturase Gene in Fluridone-Resistant Hydrilla (Hydrilla verticillata) Biotypes in Florida

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 412-420 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
Fredy Altpeter ◽  
William T. Haller
Keyword(s):  
Herbicide Resistance ◽  
Single Point ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Phytoene Desaturase ◽  
Day Length ◽  
Single Point Mutation ◽  
Aquatic Weed ◽  
Systemic Control

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. One susceptible and five fluridone-resistant biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Because fluridone is an inhibitor of the enzyme phytoene desaturase (PDS), the gene for PDS (pds) was cloned from fluridone-susceptible and -resistant hydrilla biotypes. Somatic mutations in amino acid 304 of hydrilla PDS are known to confer herbicide resistance. We determinedpdssequence from these hydrilla biotypes at planting and 12-mo after planting. Two independent mutations at the arginine 304 codon ofpdswere found in the resistant hydrilla plants. The codon usage for arginine 304 is CGT, and a single point mutation yielding either serine (AGT) or histidine (CAT) was identified in different resistant hydrilla biotypes. There were no differences at codon 304 in the PDS protein of any hydrilla biotype 12-mo after planting. Several other mutations were also found in resistantpdsalleles, though their possible role in herbicide resistance is unclear.

Growth and Reproductive Physiology of Fluridone-Susceptible and -resistant Hydrilla (Hydrilla verticillata) Biotypes

Weed Science ◽  
2007 ◽  
Vol 55 (5) ◽  
pp. 441-445 ◽  
Author(s):  
Atul Puri ◽  
Gregory E. MacDonald ◽  
William T. Haller ◽  
Megh Singh
Keyword(s):  
United States ◽  
Hydrilla Verticillata ◽  
The United States ◽  
Reproductive Physiology ◽  
Day Length ◽  
Aquatic Weed ◽  
Environment Protection ◽  
Economic Problems ◽  
Systemic Control

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only U.S. Environment Protection Agency (USEPA)–approved herbicide that provides relatively long-term systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Several biotypes of hydrilla varying in resistance levels were maintained in 950-L tanks under ambient sunlight and day-length conditions from September 2004 to September 2005 in absence of fluridone. Phenotypic measurements were performed during this 1-yr period to monitor differences in growth and reproductive physiology. All fluridone-resistant biotypes (except R3) were growing at the same rate or greater than the susceptible hydrilla. These data suggested that there are no deleterious effects on growth and reproductive physiology because of development of fluridone resistance. Aggressive spread of fluridone-resistant dioecious hydrilla in aquatic ecosystems can severely affect hydrilla management and, consequently, cause substantial and long-lasting ecological and economic problems throughout the southern United States.

scholarly journals Karyotype analysis, DNA content and molecular screening in Lippia alba (Verbenaceae)

2011 ◽  
Vol 83 (3) ◽  
pp. 993-1006 ◽  
Author(s):  
Patrícia M.O. Pierre ◽  
Saulo M. Sousa ◽  
Lisete C. Davide ◽  
Marco A. Machado ◽  
Lyderson F. Viccini
Keyword(s):  
Genetic Variation ◽  
Dna Content ◽  
Chromosome Numbers ◽  
Rapd Markers ◽  
Nuclear Dna ◽  
Pollen Viability ◽  
Flow Cytometric Analysis ◽  
Nuclear Dna Content ◽  
Ploidy Levels ◽  
Lippia Alba

Cytogenetic analyses, of pollen viability, nuclear DNA content and RAPD markers were employed to study three chemotypes of Lippia alba (Mill.) (Verbenaceae) in order to understand the genetic variation among them. Different ploidy levels and mixoploid individuals were observed. This work comprises the first report of different chromosome numbers (cytotypes) in L. alba. The chromosome numbers of La2-carvone and La3-linalool chemotypes suggested that they are polyploids. Flow cytometric analysis showed an increase of nuclear DNA content that was not directly proportional to ploidy level variation. A cluster analysis based on RAPD markers revealed that La3-linalool shares genetic markers with La1-citral and La2-carvone. The analysis showed that the majority of genetic variation of La3-linalool could be a consequence of ixoploidy. ur data indicates that sexual reproduction aong those three chemotypes is unlikely and suggests the beginning of reproductive isolation. The results demonstrated that chromosome analysis, nuclear DNA content estimation and RAPD markers constitute excellent tools for detecting genetic variation among L. alba chemotypes.

scholarly journals Genome Size and Karyotype Studies in Five Species of Lantana (Verbenaceae)

HortScience ◽  
2021 ◽  
pp. 1-5
Author(s):  
S. Brooks Parrish ◽  
Renjuan Qian ◽  
Zhanao Deng
Keyword(s):  
United States ◽  
Genome Size ◽  
Dna Content ◽  
Chromosome Numbers ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
The United States ◽  
Ploidy Levels ◽  
Chromosome Group ◽  
Group 3

Lantana species are an important component of the U.S. environmental horticulture industry. The most commonly produced and used species are L. camara and, on a smaller scale, L. montevidensis. Both were introduced to the United States from Central and/or South America. Lantana species native to the continental United States include L. canescens, L. depressa, L. involucrata, etc. and most of them have not been well exploited. This study was conducted to obtain information about somatic chromosome numbers, karyotypes, and genome size of these five species. Nuclear DNA content in these species ranged from 2.74 pg/2C (L. involucrata) to 6.29 pg/2C (L. depressa var. depressa). Four chromosome numbers were observed: 2n = 2x = 22 in L. camara ‘Lola’ and ‘Denholm White’, 2n = 4x = 44 in L. depressa var. depressa, 2n = 2x = 24 in L. canescens and L. involucrata, and 2n = 3x = 36 in L. montevidensis. Two basic chromosome numbers were observed: x = 11 in L. camara and L. depressa var. depressa, and x = 12 in L. canescens, L. involucrata, and L. montevidensis. Analysis of somatic metaphases resulted in formulas of 20m + 2sm for L. camara ‘Lola’ and ‘Denholm White’, 12m + 12sm for L. canescens, 44m for L. depressa var. depressa, 10m + 14sm for L. involucrata, and 32m + 4sm for L. montevidensis. Satellites were identified in all five species, but were associated with a different chromosome group in different species. L. depressa var. depressa had the longest total chromatin length (146.78 µm) with a range of 1.88 to 4.41 µm for individual chromosomes. The maximum arm ratio was observed in L. canescens, with a ratio of 2.5 in chromosome group 3. L. depressa var. depressa was the only species that had all of its centromeres located in the median region of the chromosome. The results show significant differences in nuclear DNA content, chromosome number, and karyotype among three native and two introduced lantana species and will help to identify, preserve, protect, and use native lantana species. The information will be helpful in assessing the ploidy levels in the genus by flow cytometry.

scholarly journals Variation in Ploidy Levels and Reproductive Pathways Among Flowering Crabapples

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 773B-773
Author(s):  
Thomas Ranney* ◽  
Thomas Eaker
Keyword(s):  
Ploidy Level ◽  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Unreduced Gametes ◽  
Breeding Programs ◽  
Ploidy Levels ◽  
Level Measurement ◽  
Dna Contents

Information on ploidy levels is extremely valuable for use in plant breeding programs. Fertility, crossability, and heritability of traits are all influenced by ploidy levels. Knowledge of reproductive pathways, including occurrence of apomixes, pseudogamy, and formation of unreduced gametes can also be important information for developing breeding strategies. Although ploidy level can be determined by counting chromosomes, flow cytometry provides a reliable and much faster means for determination of nuclear DNA content and associated ploidy level. Measurement of ploidy levels of seeds (embryo and endosperm) can also provide useful insights into reproductive pathways. The objective of this study was to determine the approximate genome size, estimated ploidy level, and range of reproductive pathways of a diverse collection of flowering crapbapples (Malus spp.). Genome sizes were calculated as nuclear DNA content for unreduced tissue (2C). Results from the taxa included in our survey showed DNA contents ranging from 1.52 to 1.82 for diploids, 2.40 to 2.62 for triploids, and 3.36 to 3.74 pg/2C for tetraploids. Based on these ranges, we identified 43 diploid, 10 triploid, and 4 tetraploid crabapple taxa in this collection. Results from open pollinated seeds and seedlings demonstrated a variety of reproductive pathways including apomixes and unreduced gametes. This research provides information on ploidy levels and reproductive pathways of flowering crabapples and will allow for more systematic and efficient progress in the development of improved cultivars.

Inhibition of cell division during cabbage (Brassica oleraceaL.) seed germination

1997 ◽  
Vol 7 (4) ◽  
pp. 333-340 ◽  
Author(s):  
Krzysztof Górnik ◽  
Renato D. de Castro ◽  
Yongqing Liu ◽  
Raoul J. Bino ◽  
Steven P. C. Groot
Keyword(s):  
Cell Division ◽  
Dna Replication ◽  
Seed Germination ◽  
Nuclear Dna ◽  
Flow Cytometric Analysis ◽  
Nuclear Dna Content ◽  
Root Hair Development ◽  
Dna Contents ◽  
Radicle Protrusion ◽  
Β Tubulin

AbstractLinks between germination, DNA replication and β-tubulin accumulation were studied with cabbage (Brassica oleraceaL.) seeds, by using flow cytometric analysis of nuclear DNA content and immunodetection of β-tubulin levels. The seeds were incubated in water or 0.1–500 mM hydroxyurea solutions. Radicle tips isolated from dry cabbage seeds revealed most 2C (Goor G1stage) and some 4C (G2stage) signals of nuclear DNA contents and a constitutive level of β-tubulin. The onset of DNA replication in the radicle tip was observed between 12 and 24 h of imbibition in water and was preceded by an increase of β-tubulin levels. Incubation of the seeds in 1 mM hydroxyurea retarded DNA replication, whereas an arrest of DNA replication occurred upon incubation in 10 mM hydroxyurea or higher concentrations. The arrest of DNA replication and cell division did not block radicle protrusion and allowed some extension of the radicle. This demonstrated that DNA replication is not a prerequisite for radicle protrusion and initial extension. However, further seedling development, including root growth and root hair development, was dependent on DNA replication. Accumulation of β-tubulin was not affected by hydroxyurea. Thus, it can be deduced that both DNA replication and β-tubulin accumulation are two parallel and independent cell cycle events during seed germination.

Stability of Fluridone-Resistant Hydrilla (Hydrilla verticillata) Biotypes over Time

Weed Science ◽  
2007 ◽  
Vol 55 (1) ◽  
pp. 12-15 ◽  
Author(s):  
Atul Puri ◽  
G. E. MacDonald ◽  
W. T. Haller
Keyword(s):  
Hydrilla Verticillata ◽  
The United States ◽  
Time Interval ◽  
Aquatic Weed ◽  
Atmospheric Conditions ◽  
Carotene Content ◽  
Systemic Control ◽  
Β Carotene ◽  
Over Time

Hydrilla is one of the most serious aquatic weed problems in the United States, and fluridone is the only herbicide approved by the U.S. Environment Protection Agency that provides systemic control. Recently, hydrilla biotypes with varying levels of fluridone resistance have been documented in Florida. Hydrilla biotypes of varying fluridone resistance levels were maintained in 900-L tanks under natural atmospheric conditions from September 2004 to September 2005 in the absence of fluridone. Hydrilla shoot tips were collected from each biotype during September 2004 (at planting), December 2004 (3 mo after planting [MAP]), March 2005 (6 MAP), June 2005 (9 MAP), and September 2005 (12 MAP) and exposed to 5, 10, 15, 20, 30, and 50 µg L−1fluridone to assess changes in susceptibility to this herbicide over time. Nonlinear regression analysis was used to calculate EC50values for phytoene and β-carotene (effective fluridone concentration to increase/decrease the phytoene/β-carotene content in hydrilla plant tissue by 50% over the untreated control) at each time interval. EC50values did not change in the susceptible hydrilla biotype over time. The EC50values for phytoene and β-carotene for the susceptible biotype were 7.5 and 8.9 µg L−1, respectively, at planting and 7.6 and 9.4 µg L−1, respectively, at 12 MAP. Resistant hydrilla biotypes (R1–R5) also showed no change in EC50phytoene values over time. Although, EC50β-carotene values in resistant biotypes R1, R3, R4, and R5 did not change over time, R2 recorded a reduction in EC50β-carotene at 12 MAP. Also, a 0.5-point decrease in resistance factor was observed for all resistant biotypes. Future long-term studies are needed to evaluate stability of resistant hydrilla biotypes in the absence of fluridone selection pressure.

Genome size and nucleotypic variation in Malus germplasm

Genome ◽  
2009 ◽  
Vol 52 (2) ◽  
pp. 148-155 ◽  
Author(s):  
Schuyler S. Korban ◽  
Wannasiri Wannarat ◽  
Charlotte M. Rayburn ◽  
Tatiana C. Tatum ◽  
A. Lane Rayburn
Keyword(s):  
Genome Size ◽  
Flow Cytometric Analysis ◽  
Internal Standard ◽  
The United States ◽  
Mean Value ◽  
Ploidy Levels ◽  
Flow Cytometric ◽  
Malus Species ◽  
Leaf Tissues ◽  
Stomatal Length

The genus Malus has anywhere between 25 and 33 species along with several subspecies. Malus species as well as clones within the same species have varying ploidy levels, as these are more than likely collected from different trees and (or) from different locations. In recent years, large numbers of Malus germplasm accessions have been collected and maintained at the United States National Germplasm Clonal Repository; however, genome sizes of this material have not yet been determined. In this study, leaf tissues from young grafted trees of 100 Malus species and hybrids growing in a nursery at the University of Illinois were collected and immediately used for extracting nuclei. Leaf tissues from apple and maize line W-22, used as an internal standard, were co-chopped and prepared for flow cytometric analysis. Apple nuclei were stained with propidium iodide, an intercalating dye, and a minimum of 8000 nuclei per sample were analyzed. Mean fluorescence of apple nuclei was then determined. A total of four replications per sample was used. Among 100 Malus accessions analyzed, one tetraploid, three triploid, and 96 diploid genotypes were identified. Significant differences in genome size were identified among the three ploidy types observed and also within diploid genotypes. The 2C mean value for tetraploids was 3.13 pg and ranged from 2.27 to 2.41 pg for triploids, whereas 2C values for diploids ranged between 1.44 and 1.72 pg. In addition, leaf impressions of young, fully expanded leaves were collected from young trees of 10 selected genotypes based on their ploidy and flow cytometric analysis and used to measure the nucleotypic parameter stomatal length. Ten stomata were measured per slide, three slides were analyzed per leaf, and three leaves were analyzed per accession. Overall, mean length of stomata ranged between 19.47 μm (diploid) and 27.6 μm (tetraploid), indicating that stomatal length in a tetraploid Malus genotype was 1.4-fold higher than that of a diploid genotype. A positive correlation between genome size and the nucleotypic parameter stomatal length was observed.

Flow cytometric analysis of nuclear DNA content in Musa

1999 ◽  
Vol 98 (8) ◽  
pp. 1344-1350 ◽  
Author(s):  
M. A. Lysák ◽  
M. Dolez˘elová ◽  
J. P. Horry ◽  
R. Swennen ◽  
J. Dolez˘el
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Flow Cytometric Analysis ◽  
Nuclear Dna Content ◽  
Flow Cytometric
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