Phytotoxic and Antifungal Activity of (-)-Penienone Produced by Penicillium palitans (Ascomycota) Isolated from Deep Sea Sediments in the Southern Ocean, Maritime Antarctica.

Metabolites isolated from Penicillium palitans, obtained from deep sea sediments in the maritime Antarctica, were investigated for phytotoxic and antifungal activities. The fungus was submitted to solid state fermentation, and its crude extract was produced. Chromatographic separations of the P.

Characterization of the Phytotoxic Potential of Seven spp. Essential Oils: Analyzing Active Compounds through Gas Chromatography-Mass Spectrometry Molecular Networking.

In recent years, there has been a need for environmentally friendly compounds for weed management in agriculture. This study is aimed to assess the phytotoxic constituents of oils obtained from oleoresins of seven species (known as copaiba oils). Copaiba oils were separated from the resins by hydro-distillation, and the distillates were analyzed using gas chromatography-mass spectrometry (GC-MS) to characterize their chemical compositions.

Molecular Targets of Herbicides and Fungicides─Are There Useful Overlaps for Fungicide Discovery?

New fungicide modes of action are needed for fungicide resistance management strategies. Several commercial herbicide targets found in fungi that are not utilized by commercial fungicides are discussed as possible fungicide molecular targets. These are acetyl CoA carboxylase, acetolactate synthase, 5-enolpyruvylshikimate-3-phosphate synthase, glutamine synthase, phytoene desaturase, protoporphyrinogen oxidase, long-chain fatty acid synthase, dihydropteroate synthase, hydroxyphenyl pyruvate dioxygenase, and Ser/Thr protein phosphatase.

Antifungal and Phytotoxic Activities of Isolated Compounds from Stems.

The identification of natural and environmentally friendly pesticides is a key area of interest for the agrochemical industry, with many potentially active compounds being sourced from numerous plant species. In this study, we report the bioassay-guided isolation and identification of phytotoxic and antifungal compounds from the ethyl acetate extract of stems. We identified eight compounds, consisting of two coumarins and six alkaloids.

Synthesis, Herbicidal Activity, and Structure-Activity Relationships of O-Alkyl Analogues of Khellin and Visnagin.

Khellin and visnagin furanochromones were recently reported as potential new bioherbicides with phytotoxic activities comparable to those of some commercially available herbicides. In this study, we examined the effect of O-alkylation and O-arylalkylation of both khellin and visnagin on its effect on herbicidal and antifungal activity. Synthetic analogues included O-demethyl khellin and visnagin, acetylated O-demethyl khellin and visnagin, O-benzylated demethyl khellin and visnagin, four O-demethyl alkylated khellin analogues, and six O-demethyl alkylated visnagin analogues, many of which are reported here for the first time.

The Chlamydomonas reinhardtii chloroplast envelope protein LCIA transports bicarbonate in planta.

LCIA (low CO2-inducible protein A) is a chloroplast envelope protein associated with the CO2-concentrating mechanism of the green alga Chlamydomonas reinhardtii. LCIA is postulated to be a HCO3- channel, but previous studies were unable to show that LCIA was actively transporting bicarbonate in planta. Therefore, LCIA activity was investigated more directly in two heterologous systems: an Escherichia coli mutant (DCAKO) lacking both native carbonic anhydrases and an Arabidopsis mutant (βca5) missing the plastid carbonic anhydrase βCA5.

Spliceostatin C, a component of a microbial bioherbicide, is a potent phytotoxin that inhibits the spliceosome.

Spliceostatin C (SPC) is a component of a bioherbicide isolated from the soil bacterium . The chemical structure of SPC closely resembles spliceostatin A (SPA) which was characterized as an anticancer agent and splicing inhibitor. SPC inhibited the growth of seedlings with an IC50 value of 2.

Evaluation of the phytotoxic and antifungal activity of C -sesquiterpenoids as potential biopesticides.

Background: Natural products are a promising source for the development of new pesticides with alternative mechanisms of action. In this study, we evaluated the phytotoxic and antifungal activity of a novel family of natural C -sesquiterpenoids and performed a study of the effect caused by the elimination of the α-methylene-γ-butyrolactone system and its importance to their biological activity.

Results: Many tested compounds exhibited a strong phytotoxic activity.

Synthesis, Crystal Structure, Herbicidal Activity, and SAR Study of Novel -(Arylmethoxy)-2-chloronicotinamides Derived from Nicotinic Acid.

Nicotinic acid, also known as niacin, is a natural product, which is widely found in plants and animals. To discover novel natural-product-based herbicides, a series of -(arylmethoxy)-2-chloronicotinamides were designed and synthesized. Some of the new -(arylmethoxy)-2-chloronicotinamides exhibited excellent herbicidal activity against (bentgrass) at 100 μM.

In vivo assembly of the sorgoleone biosynthetic pathway and its impact on agroinfiltrated leaves of Nicotiana benthamiana.

Sorgoleone, a hydrophobic compound exuded from root hair cells of Sorghum spp., accounts for much of the allelopathic activity of the genus. The enzymes involved in the biosynthesis of this compound have been identified and functionally characterized.

Proving the Mode of Action of Phytotoxic Phytochemicals.

Knowledge of the mode of action of an allelochemical can be valuable for several reasons, such as proving and elucidating the role of the compound in nature and evaluating its potential utility as a pesticide. However, discovery of the molecular target site of a natural phytotoxin can be challenging. Because of this, we know little about the molecular targets of relatively few allelochemicals.

Synthesis of Pyranopyrans Related to Diplopyrone and Evaluation as Antibacterials and Herbicides.

Stereoselective syntheses of new pyranopyrans that are related to the natural product diplopyrone, which is a phytotoxin implicated in cork oak decline, have been achieved from carbohydrate starting materials in two approaches that are based on -glycosides as key intermediates. A -alkynyl glycoside prepared by Ferrier rearrangement was used as the precursor to a new pyranopyran alkyne that showed potent antibacterial activity against the common bacterial pathogen that causes enteric septicemia in catfish. The -alkynyl glycoside also showed herbicidal activity.

Synthesis and Pesticidal Activities of New Quinoxalines.

Natural products are a source of many novel compounds with biological activity for the discovery of new pesticides and pharmaceuticals. Quinoxaline is a fused -heterocycle in many natural products and synthetic compounds, and seven novel quinoxaline derivatives were designed and synthesized three steps. Pesticidal activities of title quinoxaline derivatives were bioassayed.

Secondary metabolites of , a plant collected from the Sicilian Island of Lampedusa.

An investigation of the secondary metabolites was carried out on collected from Lampedusa, the largest island of the Pelagie archipelago, located about 100 km from the North African coast and 200 km from the coast of Sicily. Ten compounds were isolated and found to belong to different classes of natural products as chromenes, cyclohexanones, furanyl, bis-furanyl and furanone polyphenols, and acrylates. Compounds , , and were slightly phytotoxic to lettuce reaching phytotoxicity of 1 (, and ) and 2 () using a 1-5 point scale.

The Contribution of Romidepsin to the Herbicidal Activity of Biopesticide.

The culture broth of strain A396 is herbicidal to a number of weed species with greater observed efficacy against broadleaf than grass weeds. A portion of this activity is attributed to romidepsin, a 16-membered cyclic depsipeptide bridged by a 15-membered macrocyclic disulfide. Romidepsin, which is present in small amounts in the broth (18 to 25 μg mL), was isolated and purified using standard chromatographic techniques.

Transcriptome responses to the natural phytotoxin t-chalcone in Arabidopsis thaliana L.

Background: New modes of action are needed for herbicides. The flavonoid synthesis intermediate t-chalcone causes apoptosis-like symptoms in roots and bleaching of shoots of Arabidospsis, suggesting a unique mode of action as a phytotoxin.

Results: Using RNA-Seq, transcriptome changes were monitored in Arabidopsis seedlings during the first 24 h of exposure (at 1, 3, 6, 12 and 24 h) to 21 μm t-chalcone (I dose), examining effects on roots and shoots separately.

A cytochrome P450 CYP71 enzyme expressed in Sorghum bicolor root hair cells participates in the biosynthesis of the benzoquinone allelochemical sorgoleone.

Sorgoleone, a major component of the hydrophobic root exudates of Sorghum spp., is probably responsible for many of the allelopathic properties attributed to members of this genus. Much of the biosynthetic pathway for this compound has been elucidated, with the exception of the enzyme responsible for the catalysis of the addition of two hydroxyl groups to the resorcinol ring.

Identification and characterization of a solute carrier, CIA8, involved in inorganic carbon acclimation in Chlamydomonas reinhardtii.

The supply of inorganic carbon (Ci) at the site of fixation by Rubisco is a key parameter for efficient CO2 fixation in aquatic organisms including the green alga, Chlamydomonas reinhardtii. Chlamydomonas reinhardtii cells, when grown on limiting CO2, have a CO2-concentrating mechanism (CCM) that functions to concentrate CO2 at the site of Rubisco. Proteins thought to be involved in inorganic carbon uptake have been identified and localized to the plasma membrane or chloroplast envelope.

A robust protocol for efficient generation, and genomic characterization of insertional mutants of .

Background: Random insertional mutagenesis of using drug resistance cassettes has contributed to the generation of tens of thousands of transformants in dozens of labs around the world. In many instances these insertional mutants have helped elucidate the genetic basis of various physiological processes in this model organism. Unfortunately, the insertion sites of many interesting mutants are never defined due to experimental difficulties in establishing the location of the inserted cassette in the Chlamydomonas genome.