2,2?-OXO-1,1?-azobenzene: Selective toxicity of rye (Secale cereale L.) allelochemicals to weed and crop species: II

Chase, William R.; Nair, Muraleedharan G.; Putnam, A. R.

doi:10.1007/bf00994418

Cited by 73 publications

(38 citation statements)

References 18 publications

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“…However, DIBOA is unstable with a half-life of 1 day or less in an aqueous solution (pH 5-7) at room temperature and rapidly hydrolyzes into the less toxic BOA (Bredenberg et al, 1962, in Fomsgaard et al 2004). BOA (benzoxazolin-2(3H)-one), in turn, can be broken down by microbes into the more toxic allelochemical 2-amino-phenoxazin-3-one (APO) (Chase et al 1991;Gagliardo and Chilton 1992). Because of the difference in toxicity of the subsequent hydroxamic acid derivatives and the dependence of their half-lives on many factors, including the prevailing temperature and soil moisture, temporal patterns of phytotoxicity will be difficult to predict.…”

Section: Discussionmentioning

confidence: 99%

Cover crop residue management for optimizing weed control

Kruidhof

Bastiaans²,

Kropff³

2008

Plant Soil

105

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Although residue management seems a key factor in residue-mediated weed suppression, very few studies have systematically compared the influence of different residue management strategies on the establishment of crop and weed species. We evaluated the effect of several methods of pre-treatment and placement of winter rye (Secale cereale L.) and winter oilseed rape (Brassica napus L.) residue on seedling emergence under field conditions. For both species two cultivars, differing in allelochemical content, were used. Residues incorporated in the upper soil layer exerted a large inhibitory effect on the establishment of the relatively early emerging lettuce (Lactuca sativa L.) and spinach (Spinacia oleracea L.) seedlings, whereas the inhibitory effect on the slightly later emerging Stellaria media L. seedlings was variable, and often a stimulatory effect on the very late emerging Chenopodium album L. seedlings was observed. Differences between cover crop cultivars were minor. For winter oilseed rape residue, pre-treatment strongly affected the time-course of residue-mediated effects. Finely ground residues were only inhibitory to seedling establishment during the first two to three weeks, whereas cut residues became inhibitory after this period. For winter rye, residue placement was most important. Residue incorporation gave variable results, whereas placement of winter rye residue on top of the soil inhibited the emergence of all receptor species. In conclusion, the optimal residue management strategy for weed suppression depends both on the cover crop species used and the target weed species.

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Section: Discussionmentioning

confidence: 99%

Cover crop residue management for optimizing weed control

Kruidhof

Bastiaans²,

Kropff³

2008

Plant Soil

105

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“…When BOA and its related products are exuded as active plant metabolites from the roots into the soil, they can be absorbed and translocated into other crop plants to cause physiological disturbances that can even include declines in crop yields (17). This phenomenon has been demonstrated in various test plants, such as Lactuca sativa (18), Lepidium sativum (19), Avena sativa (20) and Cucumis sativus (21). Therefore, reducing the inhibitory effect of BOA derivatives on economic crops through the use of microbial metabolic processes is imperative.…”

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confidence: 99%

Metabolic Pathway Involved in 6-Chloro-2-Benzoxazolinone Degradation by Pigmentiphaga sp. Strain DL-8 and Identification of the Novel Metal-Dependent Hydrolase CbaA

Dong

Wang

Huang

et al. 2016

Appl Environ Microbiol

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ABSTRACT6-Chloro-2-benzoxazolinone (CDHB) is a precursor of herbicide, insecticide, and fungicide synthesis and has a broad spectrum of biological activity. Pigmentiphaga sp. strain DL-8 can transform CDHB into 2-amino-5-chlorophenol (2A5CP), which it then utilizes as a carbon source for growth. The CDHB hydrolase (CbaA) was purified from strain DL-8, which can also hydrolyze 2-benzoxazolinone (BOA), 5-chloro-2-BOA, and benzamide. The specific activity of purified CbaA was 5,900 U · mg protein ؊1for CDHB, with K m and k cat values of 0.29 mM and 8,500 s ؊1 , respectively. The optimal pH for purified CbaA was 9.0, the highest activity was observed at 55°C, and the inactive metal-free enzyme could be reactivated by Mg 2؉ , Ni 2؉ , Ca 2؉ , or Zn 2؉ . Based on the results obtained for the CbaA peptide mass fingerprinting and draft genome sequence of strain DL-8, cbaA (encoding 339 amino acids) was cloned and expressed in Escherichia coli BL21(DE3). CbaA shared 18 to 21% identity with some metal-dependent hydrolases of the PF01499 family and contained the signature metal-binding motif Q 127 XXXQ 131 XD 133 XXXH 137 . The conserved amino acid residues His288 and Glu301 served as the proton donor and acceptor. E. coli BL21(DE3-pET-cbaA) resting cells could transform 0.2 mM CDHB into 2A5CP. The mutant strain DL-8⌬cbaA lost the ability to degrade CDHB but retained the ability to degrade 2A5CP, consistent with strain DL-8. These results indicated that cbaA was the key gene responsible for CDHB degradation by strain DL-8. IMPORTANCE2-Benzoxazolinone (BOA) derivatives are widely used as synthetic intermediates and are also an important group of allelochemicals acting in response to tissue damage or pathogen attack in gramineous plants. However, the degradation mechanism of BOA derivatives by microorganisms is not clear. In the present study, we reported the identification of CbaA and metabolic pathway responsible for the degradation of CDHB in Pigmentiphaga sp. DL-8. This will provide microorganism and gene resources for the bioremediation of the environmental pollution caused by BOA derivatives. 6-Chloro-2-benzoxazolinone (CDHB) is the precursor of fenoxaprop-p-ethyl (FE) and metamifop synthesis (1). FE is a postemergence aryloxyphenoxy propionate (AOPP) herbicide that is used to control annual and perennial weeds in crops, such as soybean, turf, and wheat (2, 3). Many studies have demonstrated that FE can be hydrolyzed to fenoxaprop acid (FA) and further transformed into CDHB and 2-(4-hydroxyphenoxy)-propionic acid (HPP) by soil microorganisms (4-6). Recently, the hydrolysis of FE to FA by several esterases from different microorganisms has been reported (7-9). However, the underlying genes and the metabolic pathway responsible for the degradation of CDHB in microorganisms are unknown.CDHB is a type of 2-benzoxazolinone (BOA) derivative. BOA is widely used as a synthetic intermediate of related derivatives and is an important group of allelochemicals that respond to tissue damage or pathogen attack in gramineous plants, s...

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“…Seed germination assays (Barnes & Putnam, 1987;Pérez, 1990;Chase et al, 1991) showed that species with small seeds were more sensitive, and hence were inhibited more than larger seeded species when exposed to similar concentration of the allelochemicals. Seedling parameters also had no significant reduction.…”

Section: Discussionmentioning

confidence: 99%

Mesquite (Prosopis juliflora DC.) has stimulatory effect on nitrate reductase activity in rice seedlings

Shaik¹,

Mehar²

2016

JEBAS

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Prosopis juliflora is an invasive and allelopathic plant widespread in most parts of the world. P. juliflora is known to influence the growth of plants growing in its vicinity by the release of the allelochemicals during the decomposition of its litter. The negative effect is manifested by inhibition of the various physiological processes of the target plants. In the present study the effect of aqueous leaf extract of P. juliflora on the nitrogen metabolism of rice seedlings was assessed through the means of estimation of nitrate reductase (NR) activity of rice seedlings. For the study, aqueous leaf extract of dry mature leaves was prepared. From this, three concentrations viz., 1%, 10%, and 25% of the leaf extract were prepared by diluting with distilled water, while distilled water served as control. Rice seeds were incubated in different concentrations of extract for 10 days. Germination data was recorded and used for calculating the germination indices. After 10 days of exposure to the extract, seedlings were harvested and measurements for root and shoot length, fresh weights of root, shoot, and seed was taken and nitrate reductase activity of the seedlings was assayed. Germination and phenotypic results showed no negative affect by the extract. The activity of NR significantly increased with increase in the concentration of the extract. Our study revealed that the activity of NR was promoted by the extract addition.

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2,2?-OXO-1,1?-azobenzene: Selective toxicity of rye (Secale cereale L.) allelochemicals to weed and crop species: II

Cited by 73 publications

References 18 publications

Cover crop residue management for optimizing weed control

Cover crop residue management for optimizing weed control

Metabolic Pathway Involved in 6-Chloro-2-Benzoxazolinone Degradation by Pigmentiphaga sp. Strain DL-8 and Identification of the Novel Metal-Dependent Hydrolase CbaA

Mesquite (Prosopis juliflora DC.) has stimulatory effect on nitrate reductase activity in rice seedlings

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