See also: National
Technical Information Service (NTIS) Reports
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15668922
Pest Manag Sci. 2005 Mar;61(3):258-68.
Molecular evolution of herbicide resistance
to phytoene desaturase inhibitors in Hydrilla verticillata and
its potential use to generate herbicide-resistant crops.
Arias RS, Netherland MD, Scheffler BE,
Puri A, Dayan FE.
USDA/ARS, Natural Products Utilization Research Unit, PO Box
8048, University, Mississippi 38677, USA.
Hydrilla [Hydrilla verticillata (Lf) Royle] is one of the most
serious invasive aquatic weed problems in the USA. This plant
possesses numerous mechanisms of vegetative reproduction that
enable it to spread very rapidly. Management of this weed has
been achieved by the systemic treatment of water bodies with
the herbicide fluridone. At least three dioecious fluridone-resistant
biotypes of hydrilla with two- to fivefold higher resistance
to the herbicide than the wild-type have been identified. Resistance
is the result of one of three independent somatic mutations
at the arginine 304 codon of the gene encoding phytoene desaturase,
the molecular target site of fluridone. The specific activities
of the three purified phytoene desaturase variants are similar
to the wild-type enzyme. The appearance of these herbicide-resistant
biotypes may jeopardize the ability to control the spread of
this non-indigenous species to other water bodies in the southern
USA. The objective of this paper is to provide general information
about the biology and physiology of this aquatic weed in relation
to its recent development of resistance
to the herbicide fluridone, and to discuss how this discovery
might lead to a new generation of herbicide-resistant crops.
Copyright 2005 Society of Chemical Industry
PMID: 15668922 [PubMed - in process]
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15367135
Mol Ecol. 2004 Oct;13(10):3229-37.
Somatic mutation-mediated evolution of
herbicide resistance in the nonindigenous invasive plant hydrilla
(Hydrilla verticillata).
Michel A, Arias RS, Scheffler BE, Duke
SO, Netherland M, Dayan FE.
USDA/ARS, Natural Products Utilization Research Unit, PO Box
8048, University, Mississippi 38677, USA.
Hydrilla (Hydrilla verticillata L.f. Royle) was introduced
to the surface water of Florida in the 1950s and is today one
of the most serious aquatic weed problems in the USA. As a result
of concerns associated with the applications of pesticides to
aquatic systems, fluridone is the only USEPA-approved chemical
that provides systemic control of hydrilla. After
a decrease in fluridone's efficacy at controlling hydrilla,
200 Florida water bodies were sampled to determine the extent
of the problem and the biological basis for the reduced efficacy.
Our studies revealed that hydrilla phenotypes
with two- to six-fold higher fluridone resistance were present
in 20 water bodies. Since fluridone is an inhibitor of
the enzyme phytoene desaturase (PDS), the gene for PDS (pds)
was cloned from herbicide-susceptible and -resistant hydrilla
plants. We report for the first time in higher plants three
independent herbicide-resistant hydrilla biotypes arising from
the selection of somatic mutations at the arginine 304 codon
of pds. The three PDS variants had specific activities similar
to the wild-type enzyme but were two to
five times less sensitive to fluridone. In vitro activity
levels of the enzymes correlated with in vivo resistance of
the corresponding biotypes. As hydrilla
spread rapidly to lakes across the southern United States in
the past, the expansion of resistant biotypes is likely to pose
significant environmental challenges in the future.
PMID: 15367135 [PubMed - in process]
Applied Clay Science Volume 24, Issues 3-4 , February 2004,
Pages 167-175
Third Mediterranean Clay Meeting
Fluridone adsorption–desorption
on organo-clays
Dana Yaron-Marcovich, Shlomo Nir and
Yona Chen
Department of Soil and Water Sciences, Faculty of Agricultural
Food and Environmental Sciences, The Hebrew University of Jerusalem,
Rehovot 76100, Israel
The adsorption–desorption of the herbicide fluridone on
Na-montmorillonite and several organo-montmorillonite complexes
was studied at a variety of loadings of the organic cation and
pH levels. The aim was to find the organo-clay complex, which
would be an optimal adsorbent for the hydrophobic fluridone.
The organic cations studied were hexadecyltrimethylammonium
(HDTMA), benzyltriethylammonium (BTEA), benzyltrimethylammonium
(BTMA) and methylene blue (MB) at loadings equal to 25%, 50%
and 100% of the cation exchange capacity (CEC) of the clay-mineral.
The adsorbed amount of fluridone increased several-fold when
montmorillonite was preadsorbed by the organic cation HDTMA
up to its CEC and with BTMA at a loading of 5/8 of the CEC.
BTEA and MB did not improve the adsorption capacity of the clay
for fluridone. The results suggest that interactions between
the phenyl rings of the herbicide and that of a small organic
cation are geometrically easier to establish than with a larger
organic cation. A reduced interaction between the phenyl rings
of MB and those of fluridone may account for the low affinity
of fluridone adsorption on montmorillonite-MB. In all cases,
fluridone adsorption increased with decreasing pH and reached
100% for pH 2.7. Protonation of fluridone molecules with decreasing
pH would result in increased adsorption through cation exchange.
Thus, by regulating the pH, complete fluridone adsorption can
be achieved. Desorption isotherms demonstrate high degree of
irreversibility of the adsorption–desorption process and
suggest that strong binding mechanisms dominate the fluridone-clay
and organo-clay interactions. The results for fluridone adsorption–desorption
demonstrate that, for similar molecules, a clay-based slow release
formulation can be designed by first lowering the pH.
Pesticide Biochemistry and Physiology Volume 78, Issue 3 , March
2004, Pages 127-139
Death mechanisms caused by carotenoid biosynthesis
inhibitors in green and in undeveloped plant tissues
Jin-Seog Kim (a), Byung-Wook Yun (b),
Jung Sup Choi (a), Tae-Joon Kim (a), Sang-Soo Kwak (b) and Kwang-Yun
Cho (a)
(a) Biofunction Research Team, Bioorganic Science Division,
Korea Research Institute of Chemical Technology (KRICT), P.O.
Box 107, Yuseong, Taejeon 305-600, Republic of Korea
(b) Laboratory of Environmental Biotechnology, Korea Research
Institute of Bioscience and Biotechnology (KRIBB), Yuseong,
Taejeon 305-333, Republic of Korea
This study was carried out to investigate the difference in
physiological processes leading to two different responses of
albinism and necrosis to the phytoene desaturase inhibitor fluridone,
which is dependent on the developmental state of tissue at the
time of fluridone treatment. A soil-drench of fluridone solution
at the 40% growth of the 3rd leaf of maize (Zea mays L.) caused
the leaf to grow into a white/green mixed leaf; completely white
in the basal part (W), pale green in the middle part (PG), and
green in apical part of the leaf blade (G). In the PG and G,
the effective quantum yield of electron transport through photosystem
II (Yield) was significantly inhibited, Fv/Fm was decreased
but Fo increased, hydrogen peroxide was more accumulated than
untreated control, and cellular leakage was faster and more
pronounced than in the white tissue (W). In the W, however,
all of Fo, Fm, and Yield values were near zero due to loss of
chlorophyll. Moreover, there was a relatively low content of
hydrogen peroxide, slower cellular leakage and longer survival
of tissue in the W. On the other hand, the level of antioxidants
such as carotenoids, tocopherols, and ascorbic acid was lower
in the W than untreated control. However, the specific activities
of antioxidant enzymes were elevated in the W; 3.47 times in
superoxide dismutase (SOD), 3.21 times in peroxidase (POD),
1.59 times in catalase and 1.21 times in glutathione reductase.
In particular, SOD and POD activities had a tendency to be increased
during senescence. In the kinetics experiment carried out during
a senescence of the 2nd white leaf, increase of wilting and
browning began to occur prior to any significant change in MDA-equivalents,
and high reduction of carbohydrate contents occurred prior to
increase of wilting and necrosis. Carbohydrate supplement significantly
delayed the death of white leaves. Taken together, the above
results indicated that in the developed tissue, whose greening
has already taken place at the time of herbicide treatment,
its death was related to the cell destruction by excessive oxidative
stress induced through photosynthetic electron transport blockade.
Conversely, in the developing or undifferentiated tissue at
the time of herbicide treatment, that eventually grown into
a white tissue, its death seemed to be more dependent on a loss
of photosystem function followed by carbohydrate deficiency.
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12803614&dopt=Abstract
Plant Cell
Environ. 2003 Jun;26(6):867-874.
Role
of abscisic acid in cadmium tolerance of rice (Oryza sativa
L.) seedlings.
Hsu
YT, Kao CH.
Department
of Agronomy, National Taiwan University, Taipei, Taiwan, Republic
of China.
Changes
in abscisic acid (ABA) contents in Cd-treated rice (Oryza sativa
L.) seedlings of two cultivars were investigated. On treatment
with CdCl2, the ABA content rapidly increased in the leaves
and roots of Cd-tolerant cultivar (cv. Tainung 67, TNG67) but
not in the Cd-sensitive cultivar (cv. Taichung Native 1, TN1).
The reduction of transpiration rate of TN1 caused by Cd was
less than that of TNG67. Exogenous application of ABA reduced
transpiration rate, decreased Cd content, and enhanced Cd tolerance
of TN1 seedlings. Exogenous application
of the ABA biosynthesis inhibitor, fluridone, reduced ABA accumulation,
increased transpiration rate and Cd content, and decreased Cd
tolerance of TNG67 seedlings. Fluridone effect on Cd toxicity
of TNG67 seedlings was reversed by the application of ABA. The
roles of endogenous ABA in Cd tolerance of rice seedlings are
discussed and suggested.
PMID: 12803614
[PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12240995&dopt=Abstract
Z Naturforsch
[C]. 2002 Jul-Aug;57(7-8):671-9.
Bansformation
of tobacco with a mutated cyanobacterial phytoene desaturase
gene confers resistance to bleaching herbicides.
Wagner
T, Windhovel U, Romer S.
Lehrstuhl
fur Physiologie und Biochemie der Pflanzen, Universitat Konstanz,
Germany.
Carotenoids
are constituents of the photosynthetic apparatus and essential
for plant survival because of their involvement in protection
of chlorophylls against photooxidation. Certain classes of herbicides
are interfering with carotenoid biosynthesis leading to pigment
destruction and a bleached plant phenotype. One important target
site for bleaching herbicides is the enzyme phytoene desaturase
catalysing the desaturation of phytoene in zeta-carotene. This
enzymatic reaction can be inhibited by norflurazon or fluridone.
We have transformed tobacco with a mutated cyanobacterial phytoene
desaturase gene (pds) derived from the Synechococcus PCC 7942
mutant NFZ4. Characterization of the resulting transformants
revealed an up to 58 fold higher norflurazon resistance in comparison
to wild type controls. The tolerance for fluridone was also
increased 3 fold in the transgenics. Furthermore, the transformed
tobacco maintained a higher level of D1 protein of photosystem
II indicating a lower susceptibility to photooxidative damage
in the presence of norflurazon. In contrast, the genetic manipulation
did not confer herbicide resistance against zeta-carotene desaturase
inhibitors.
PMID: 12240995
[PubMed - indexed for MEDLINE]
Full report available at http://sgnis.org/publicat/papers/getsma02.pdf
Lake and Reservoir Management (2002)
18(3): 181-190
Whole Lake Fluridone Treatments for
Selective Control of Eurasian Watermilfoil: I. Application Strategy
and Herbicide Residues
Getsinger, K.D., J.D. Madsen, T.J. Koschnick,
and M.D. Netherland
The herbicide fluridone is being used
in northern lakes and reservoirs to control the exotic species
Eurasian watermilfoil (Myriophyllum spicatum L.). Since
quantitative information linking changes in plant communities
following fluridone applications is limited, particularly with
respect to water residue records, a study was conducted to investigate
the effect of low-dose treatments on the submersed plant communities
in four Michigan lakes. The overall study objective was to determine
whether plant species diversity and frequency of occurrence
were affected by low-dose fluridone applications in the year
of treatment. The primary objective of this portion of the overall
study was to provide an application strategy that would maintain
a threshold dose of fluridone, 5 mug.L-1 declining to 2 mug.L-1,
in the treated lakes to selectively control Eurasian watermilfoil.
Study lakes were 55 to 220 ha in size and contained an average
of nine species of submersed plants. Big
Crooked, Camp, Lobdell, and Wolverine lakes were treated in
mid-May 1997 with the formulation Sonar(R) AS, to yield
an initial concentration of 5 mug.L-1 fluridone in the upper
3.05 m of each lake. A sequential application of Sonar(R)AS
was conducted on each lake at 16 to 21 days after initial treatment
(DAIT), intended to re-establish a fluridone concentration of
5 mug.L-1 in the upper 3.05 m of each lake. Bass,
Big Seven, Clear, and Heron lakes received no fluridone applications
and served as untreated reference sites. Water residue
samples were collected at prescribed intervals on each fluridone-treated
lake from pretreatment up to 81 DAIT. Samples were collected
from six littoral stations and from two deep locations throughout
each take, and temperature profiles were measured at the deep
stations. Fluridone residues were analyzed using two separate
techniques, the newly developed enzyme-linked immunosorbent
assay and the standard high performance liquid chromatography
method. Fluridone levels on three Of the treated lakes met the
laboratory-derived criteria for achieving good control of Eurasian
watermilfoil by providing a peak concentration of approximately
5 mug.L-1 during the first 2 weeks posttreatment, and by maintaining
a concentration >2 mug.L-1 through 60 DAIT. Residues became
well mixed in the water column under isothermal conditions,
and thermal stratification prevented mixing of fluridone into
deeper and colder waters. Residue data indicated that thermal
stratification, or the lack thereof, at the time of herbicide
application can affect target herbicide concentrations.
Using the volume of a pre-selected depth zones to calculate
the amount of fluridone needed to achieve a particular target
concentration can result in an over- or under-dosing of a water
body.
Plant Science Volume 126, Issue 2 , 8 August 1997,
Pages 211-218
Androgenesis in Hordeum vulgare L.:
Effects of mannitol, calcium and abscisic acid on anther pretreatment
S. Hoekstra (a), S. van Bergen (a), I. R. van Brouwershaven
(a), R. A. Schilperoort (b) and M. Wang (a)
(a) Center for Phytotechnology RUL/TNO, Department of Plant
Biotechnology, Wassenaarseweg 64, 2333 AL Leiden, The Netherlands
(b) Center for Phytotechnology, Institute of Molecular Plant
Sciences, Leiden University, Wassenaarseweg 64, 2333 AL Leiden,
The Netherlands
Pretreatment-induced androgenesis of Hordeum vulgare L. cv.
Igri was investigated in order to find factors which control
optimal plant production. The influence of what is called pre-medium
and of the concentration of both mannitol and calcium were studied.
Increasing concentrations of each of the compounds, also resulting
in a higher osmolality, improved both embryo like structure
(ELS) and plant productions. Optimal ELS production was obtained
upon anther pretreatment in about 20 mM CaCl2 while optimal
plant production was obtained with anther pretreatment in about
30 mM CaCl2. In addition, it was observed that calcium could
be replaced by potassium ions. Since abscisic acid (ABA) is
involved in several developmental processes and is known to
be induced by various stresses, we studied the effects of ABA
and the ABA biosynthesis inhibitor fluridone on the induction
of androgenesis. Although external addition of ABA did not significantly
affect both ELS and plant productions during pretreatment, addition
of fluridone could dramatically reduce the production of plants.
The possible mechanism of pretreatment in induction of androgenesis
is discussed.
Soil Biology and Biochemistry Volume 26, Issue 6 , June 1994,
Pages 689-694
Reduced fluridone efficacy in soil: A possible
case for reversible microbial inactivation
Miriam Freund (a), Oded Yarden (b), Rina
Varsano (a) and Baruch Rubin (a),
(a) Department of Field Crops, Vegetables and Genetics, Faculty
of Agriculture, The Hebrew University of Jerusalem, Rehovot
76100, Israel
(b) Department of Plant Pathology and Microbiology, Faculty
of Agriculture, The Hebrew University of Jerusalem, Rehovot
76100, Israel
A reduction in efficacy of the persistent
herbicide fluridone has been observed in soils with fluridone
application history (FH soils). Fluridone activity, as
monitored by bioassay, persisted in FH soils for ca 1 week,
whereas in fluridone non-history (FNH) soils phytotoxicity could
be observed even after 3 months of exposure. Incorporation of
small volumes of FH soil were sufficient to confer rapid loss
of herbicidal activity on larger, autoclaved FNH soil volumes.
In FH soils exposed to intensive antimicrobial treatments the
activity of fluridone was restored to levels similar to those
observed in FNH soils. Autoclaving and to a lesser extent, other
disinfestation or antimicrobial measures ( irradiation, methyl
bromide, several fungicides) used to treat FH soils, exposed
test plants to phytotoxic compounds even though the herbicide
was not re-applied to the soil. Fluridone adsorption coefficients
(Ka) in FH and FNH soils were similar, suggesting that physical
adsorption of the herbicide does not play a key role in the
observed inactivation of fluridone in FH soil. The possibility
of reversible microbial inactivation of fluridone is discussed.
Phytochemistry Volume 30, Issue 3 , 1991,
Pages 815-821
Carotenoid metabolism and the biosynthesis
of abscisic acid
Andrew D. Parry and Roger Horgan
Department of Biological Sciences, The University College of
Wales, Aberystwyth, Dyfed, SY23 3DA, U.K.
The conversion of all-trans-violaxanthin
to 9?-cis-neoxanthin was shown to occur in fluridone-treated
etiolated Lycopersicon and Phaseolus seedlings, following exposure
to light. The results of deuterium oxide labelling experiments
supported this precursor/product relationship, and provided
further evidence for the origin of abscisic acid. Several apo-carotenoids,
putative by-products of abscisic acid biosynthesis, were synthesised
by chemical oxidation but were not detected in plant extracts.
In vitro, lipoxygenase cleaved neoxanthin and violaxanthin down
to small (C13) fragments. It may be that in vivo any apo-carotenoids
formed by the specific cleavage of 9?-cis-neoxanthin, during
abscisic acid biosynthesis, are rapidly metabolized by lipoxygenase
or similar enzymes.
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3771457&dopt=Abstract
J Assoc
Off Anal Chem. 1986 Sep-Oct;69(5):856-9.
Liquid
chromatographic determination of fluridone aquatic herbicide
and its metabolite in fish and crayfish.
West
SD, Day EW Jr.
A residue
method is described for determination of the aquatic herbicide
fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone)
and its metabolite (1-methyl-3-(4-hydroxyphenyl)-5-[3-(trifluoromethyl)
phenyl]-4(1H)-pyridinone) in fish and crayfish tissues.
Both compounds are extracted from tissues with methanol, and
the extracts are subjected to acidic hydrolysis to release conjugated
forms of fluridone and the metabolite. Sample extracts are purified
by liquid-liquid partitioning and Florisil Sep-Pak column chromatography.
Both compounds are separated and measured by reverse phase liquid
chromatography with UV detection at 313 nm. In the absence of
interfering peaks, the method has a detection limit of approximately
0.04 ppm of either compound. Overall, recoveries averaged 96%
for fluridone and 78% for the metabolite for all tissue types
combined.
PMID: 3771457
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=4005449&dopt=Abstract
Bull Environ
Contam Toxicol. 1985 May;34(5):696-701.
No
Abstract available
Toxicity
of fluridone in algal bioassays.
Trevors
JT, Vedelago H.
PMID:
4005449 [PubMed - indexed for MEDLINE]
Pesticide Biochemistry and Physiology Volume 17, Issue 1 , February
1982, Pages 68-75
Degradation of fluridone in submersed
soils under controlled laboratory conditions*
[*Published in cooperation with the College
of Agriculture Research Center, Washington State University,
as Scientific Paper No. 6061.]
L. Y. Marquis, R. D. Comes and C. P.
Yang
U.S. Department of Agriculture, Agricultural Research Service,
Irrigated Agriculture Research and Extension Center, Prosser,
Washington 99350, USA
The experimental, aquatic herbicide fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone)
was degraded in two submersed soils and in the water above those
soils to one acidic metabolite (identified as 1,4-dihydro-1-methyl-4-oxo-5-[3-(trifluoromethyl)phenyl]-3-pyridinecarboxylic
acid by mass spectrometry). A sandy and a silt loam soil were
treated with [14C]fluridone, immersed in water, and analyzed
after 1, 3, 5, 7, 9, and 12 months. Seven to fifteen percent
of the 14C applied to the soils was recovered in the water on
each of the various collection dates. The acidic metabolite
accounted for 86 to 93% of the radioactivity in the water fraction
7 months after treatment. The metabolite was absorbed strongly
by both soils and comprised about 60% of the total 14C in each
soil after 12 months. The remainder of the 14C in the soils
after 12 months was either the parent compound (~30%) or an
undefined insoluble residue (~10%).
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=7451395&dopt=Abstract
J Assoc
Off Anal Chem. 1980 Nov;63(6):1304-9.
Gas
chromatographic determination of fluridone aquatic herbicide
and its major metabolite in fish.
West
SD, Burger RO.
A gas-liquid
chromatographic (GLC) method is described for determining residues
of the aquatic herbicide fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone)
and its major metabolite (1-methyl-3-(4-hydroxyphenyl)-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone)
in fish. Both compounds are extracted from fish tissue with
methanol, and the extracts are subjected to acidic hydrolysis
to release conjugated forms of fluridone and the metabolite.
After purification by liquid-liquid partitioning, sample extracts
are reacted with methyl iodide to methylate the metabolite,
and then both fluridone and the metabolite are brominated with
phosphorus tribromide. After purification by Florisil column
chromatography, the derivatives are separated and measured by
electron capture GLC. The method is capable of determining approximately
0.01 ppm of both compounds in fish, and recoveries have averaged
84 +/- 14.7% for fluridone and 83 +/- 13.4% for the metabolite.
PMID: 7451395
[PubMed - indexed for MEDLINE]
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=575721&dopt=Abstract
J Agric
Food Chem. 1979 Sep-Oct;27(5):1067-72.
No
Abstract available
Dissipation
of the experimental aquatic herbicide fluridone from lakes and
ponds.
West
SD, Day EW Jr, Burger RO.
PMID:
575721 [PubMed - indexed for MEDLINE]
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