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PubMed2001

Genetic diversity of allozymes in turnip (Brassica rapa L. var. rapa) from the Nordic area.

Genetic diversity and relationships based on isozymes were studied in 31 accessions of turnip (Brassica rapa L. var. rapa). The material included varieties, elite stocks, landraces and older turnip of slash-and-burn type from the Nordic area. A total of 9 isozyme loci and 26 alleles were studied. The isozyme systems were ACO, DIA, GPI, GOT, PGM, PGD and SKD. The level of heterozygosity was reduced in the landraces, but it was high for the variety group 'Ostersundom'. Turnip has a higher genetic variation than other crops within B. rapa and than in other species with the same breeding system. The genetic diversity showed that 18.7% of the genetic variation was within the accessions, and the total H tau value was 0.358. Gpi-I and Pgd-I showed the lowest variation compared with the other loci. The cluster analysis revealed five clusters, with one main cluster including 25 of the 31 accessions. The dendrogram indicated that the variety group 'Ostersundom' clustered together whereas the variety group 'Bortfelder' was associated with country of origin. The landraces were spread in different clusters. The 'slash-and-burn' type of turnip belonged to two groups.

Agriculture↗
PubMed1988

Plant productivity in controlled environments.

To assess the cost and area/volume requirements of a farm in a space station or Lunar or Martian base, a few laboratories in the United States, the Soviet Union, France, and Japan are studying optimum controlled environments for the production of selected crops. Temperature, light, photoperiod, CO2, humidity, the root-zone environment, and cultivars are the primary factors being manipulated to increase yields and harvest index. Our best wheat yields on a time basis (24 g m-2 day-1 of edible biomass) are five times good field yields and twice the world record. Similar yields have been obtained in other laboratories with potatoes and lettuce; soybeans are also promising. These figures suggest that approximately 30 m2 under continuous production could support an astronaut with sufficient protein and about 2800 kcal day-1. Scientists under Iosif Gitelzon in Krasnoyarsk, Siberia, have lived in a closed system for up to 5 months, producing 80% of their own food. Thirty square meters for crops were allotted to each of the two men taking part in the experiment. A functional controlled-environment life-support system (CELSS) will require the refined application of several disciplines: controlled-environment agriculture, food preparation, waste disposal, and control-systems technology, to list only the broadest categories. It has seemed intuitively evident that ways could be found to prepare food, regenerate plant nutrients from wastes, and even control and integrate several subsystems of a CELSS. But could sufficient food be produced in the limited areas and with the limited energy that might be available? Clearly, detailed studies of food production were necessary.

Biomass↗
PubMed2026

Integrated metabolomics, transcriptional, and physicochemical analysis reveals key metabolites and genes associated with somatic embryogenesis in Phyllostachys pubescens.

Phyllostachys pubescens (Moso bamboo) is a significant perennial crop species that provides valuable nutritional and industrial uses, as well as carbon sequestration. Due to its remarkable growth rate, bamboo offers an ideal system for studying organogenesis, particularly in monocots. Somatic embryogenesis (SE) serves as a useful technique for crop breeding and improvement. SE in moso bamboo (Phyllostachys pubescens) remains challenging due to limited knowledge of its transcriptional and metabolomic reprogramming. To address this, we optimized callus initiation (MS + 18.1 µM 2,4-D + 8.5 µM picloram), callus proliferation (MS + 12.5 µM 2,4-D + 8.5 µM picloram), and somatic embryogenesis (MS + 1.1 µM 2,4-D + 3.3 µM metatopolin), using nodal segments as explants. UHPLC-Q-TOF-MS-based metabolite profiling revealed distinct biochemical trajectories across developmental stages of P. pubescens. NEC (non-embryogenic callus) was enriched in flavonoids, alkaloids, and saponins, while in-vitro shoots showed flavonoids and glycosides enrichment, and ex-vitro shoots showed high accumulation of glycosides and terpenoids. In contrast, EC (embryogenic callus) showed elevated levels of fatty acid derivatives (α-ESA, 26-Methyl Nigranoate), phytoalexins (Wyerone acid), sesquiterpene (Alpha-santalal, Beta-guaiene), flavonoid glycosides, and plant hormones (Cis-Zeatin, Gibberellin A45), indicating a metabolically active state supporting somatic embryogenesis. Similarly, genes and transcription factors controlling cell differentiation and embryogenesis were upregulated during SE. This study provides a comprehensive resource to facilitate future genomic and genetic investigations aimed at deciphering the molecular basis of organogenesis and advancing research on somatic embryogenesis in bamboo.

Plant Somatic Embryogenesis Techniques↗
PubMed1989

Control of water and nutrients using a porous tube: a method for growing plants in space.

A plant nutrient delivery system that uses a microporous, hydrophilic tube was developed with potential application for crop production in the microgravity of space. The tube contains a nutrient solution and delivers it to the roots. Pumps attached to the tubing create a very small suction that holds the solution within the tube. This system was used to grow wheat (Triticum aestivum cv. Yecora Rojo) for 107 days in a controlled environment at suctions of 0.40, 1.48, or 2.58 kPa. The water absorbed through the pores of the tube by baby diaper sections decreased as suction increased. Correspondingly, final plant biomass, seed number, and spikelet number also tended to decrease as suction increased. The reduced yield at higher suction suggests that the plants experienced water stress, although all suctions were below those typical of soils at field capacity.

Biomass↗
PubMed2003

Manipulation of parasitoids for aphid pest management: progress and prospects.

This paper describes research at IACR-Rothamsted on aphid parasitoid responses to semiochemical foraging stimuli, aimed at developing novel ways of manipulating these behaviours to overcome ecological constraints to biological and integrated pest control. Female parasitoids respond both to aphid sex pheromones acting as kairomones, and to aphid-induced plant volatiles, acting as synomones. A range of economically important parasitoid species respond to aphid sex pheromones, and their potential for enhancing parasitization of aphid populations has been demonstrated in the field. Commercial production of the pheromone from the plant Nepeta cataria L has been developed and strategies for its use in arable crops are being investigated. Aphid-induced plant volatiles are released systemically throughout the plant and are aphid species specific, probably induced by elicitors in aphid saliva. Aphid-infested plants can induce uninfested neighbours to release damage-related volatiles, plant-to-plant communication occurring via the rhizosphere. The plant compound cis-jasmone has been identified as a plant signal with potential for aphid control, inducing plant defence mechanisms that both deter colonising aphids and attract parasitoids and predators. Such compounds may represent a new generation of crop protectants and their further investigation and development will be aided by the tools generated by genomic and post-genomic biology.

Animals↗
PubMed1995

Metabolism of herbicides by cytochrome P450 in corn.

Cytochrome P450 monooxygenases (P450) have long been considered a potentially important enzyme system for the detoxification of herbicides in corn and other crop plants. Only recently has herbicide metabolism by P450 in corn microsomes been conclusively demonstrated. Fourteen herbicides in six chemical families have been shown to be metabolized by P450 in corn. P450 is now considered of equal importance to glutathione S-transferases for the metabolism of herbicides in corn. P450 metabolism of herbicides in corn is characterized as an inducible enzyme activity which primarily catalyses hydroxylations and demethylations of the herbicide substrates. Induction of the herbicide metabolizing activity is specific, with only slight changes in the total P450 level accompanying several-fold induction of herbicide metabolism. Turnover rates for herbicide metabolism can equal those for drug metabolism. Microsomes isolated from both shoots and roots metabolize herbicides, although the majority of activities are most fully characterized in microsomes isolated from shoots of young etiolated seedlings. Many questions concerning the P450 metabolism of herbicides in corn remain. These include determining how many P450s are involved in herbicide metabolism and how their levels are regulated. Evidence is gathering that, for a number of the herbicides presently known to be metabolized by P450 in corn, there may be relatively few or even one P450 which metabolizes all the herbicide substrates.

Cytochrome P-450 Enzyme Inhibitors↗
PubMed1988

Relaxin: a mammotropic hormone promoting growth and differentiation of the pigeon crop sac mucosa.

The pigeon crop sac is responsive to local administration of mammotropic hormones independently of systemic hormonal influences. We showed previously in mice that relaxin promotes growth of the mammary gland only after pre-treatment with estrogen. In this study we investigated whether relaxin, locally administered, has a stimulatory effect without estrogen pre-treatment. The results of this study show that relaxin stimulates the crop sac mucosa causing changes in its gross appearance and histological modifications indicating enhanced growth and differentiation of the mucosal epithelium. The effects of relaxin are dose-related, as demonstrated by the increases of the wet and dry weights, the [3H]thymidine and [3H]uridine uptakes of the mucosa, and the histochemically detectable DNA content of the mucosal epithelium. These results strengthen the idea that relaxin should be included in the list of mammotropic hormones.

Animals↗
PubMed2026

Novel Genomic Regions Associated with Multifungicide Resistance in Botrytis cinerea and Factors Impacting Greenhouse Population Structure.

The fungal plant pathogen Botrytis cinerea affects hundreds of valuable crops, including fruits, vegetables, and ornamental plants. In greenhouse production systems, B. cinerea disease management largely depends on the use of fungicides; however, the emergence of resistance to multiple fungicide classes has become a major challenge. An improved understanding of B. cinerea populations can contribute to the development of resistance management strategies. In this study, isolates (n = 276) of B. cinerea were collected from ornamental production greenhouses in Michigan, and whole-genome resequencing was performed to evaluate genetic differentiation among hosts, locations, growing cycles, and fungicide resistance. Discriminant analyses of principal components and analyses of molecular variance revealed limited genetic differentiation among isolates from different hosts, greenhouses, and years of isolate collection. In contrast, the same analyses alongside pairwise fixation indexes and an evaluation of population structure indicated significant genetic differentiation among isolates based on the number of fungicides to which they are resistant. There are two described mechanisms that confer resistance to multiple fungicides at the same time, both of which are mediated by efflux pumps. Results from a quantitative trait genome-wide association study revealed novel genomic regions associated with multifungicide resistance, including two genes that encode putative efflux pumps. An understanding of fungicide resistance patterns is essential for developing durable disease control measures. Our results highlight the importance of continued monitoring of B. cinerea populations, as the observed genetic differentiation linked to fungicide resistance emphasizes their ability to adapt to selection pressure.

Botrytis cinerea↗
PubMed2026

Advances in CRISPR multiplex gene editing to map and modify stress-responsive transcription factor networks for crop improvement.

The development of CRISPR multiplex genome-editing (MGE) tools is rapidly transforming plant functional genomics and accelerating crop improvements. By simultaneously targeting two or more DNA loci, it allows scientists to precisely edit multiple genes at the single-nucleotide level, within the target genome. Simultaneous manipulation of multiple targets has revolutionized the functional elucidation studies, particularly the dissection of complex genetic pathways. Due to its superior precision and feasibility, CRISPR-MGE is widely accepted and has largely replaced alternative editing tools such as TALENs and ZFNs. Several CRISPR-MGE strategies, including the use of individual expression cassettes, tRNA-processing enzymes, Csy4 or ribozymes, have been successfully deployed in plants. Recent advancements, such as Cpf1, transgene-free methods, or ultra-multiplexing approaches, have further refined the technology into a powerful, efficient, and robust toolkit. MGE enables complex genome editing, including multiple-gene knockouts, base alterations, transcriptional regulation, metabolic engineering, or their combinations. Consequently, it is ideal for elucidating the function of transcription factors that are key molecular players in regulating diverse plant responses, especially in stress pathways. Several stress-responsive TFs have been functionally characterized via CRISPR-MGE, and more advanced tools are being employed. This review evaluates multiplexing tools, their diverse applications, and the current progress toward developing advanced MGE tools. Ultimately, we provide evidence to encourage the use of advanced MGE tools for functional characterization studies of stress-responsive TFs, thereby highlighting their potential to accelerate crop improvement.

Gene Editing↗
PubMed1986

[Utilization of N15-labelled urea in the laying hen. 5. N15-labelling of the content and tissue of separate parts of the gastrointestinal tract].

In the series of experiments with labelled urea three colostomized laying hybrids were butchered after a six-day application of 1% urea with 96.06 atom-% 15N excess (15N') in the ration and another 2 days with a supplement of 1% unlabelled urea. Out of the individual samples from crop, gizzard, small intestine, caecum and rectum, the content of the small intestine and the caecum showed the highest labelling with greater than 1 atom-% 15N'. The TCA soluble fraction of the content of the gizzard was more highly and that of the intestines less labelled than the total nitrogen. The tissue of the gizzard is distinctly less labelled than the "omasum system" and the small intestine. The atom-% 15N' of the oesophagus with crop and glandular stomach largely showed agreement in the individual hens with that of intestinal tissue and ranged between 0.71 and 0.89 atom-%. 2% of the 15N' supplemented with the urea could be recovered in the content and the tissue of the gastro-intestinal tract.

Animals↗
PubMed2003

Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: ground-based Mars Base prototype.

Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens (TM)" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes.

Ecological Systems, Closed↗
PubMed2002

The Ustilaginales as plant pests and model systems.

The Ustilaginales are a vast and diverse group of fungi, which includes the plant pathogenic smuts that cause significant losses to crops worldwide. Members of the Ustilaginales are also valuable models for the unraveling of fundamental mechanisms controlling important biological processes. Ustilago maydis is an important fungal model system and has been well studied with regard to mating, morphogenesis, pathogenicity, signal transduction, mycoviruses, DNA recombination, and, recently, genomics. In this review we discuss the life cycles of members of the Ustilaginales and provide background on their economic impact as agricultural pests. We then focus on providing a summary of the literature with special attention to topics not well covered in recent reviews such as the use of U. maydis in mycovirus research and as a model for understanding the molecular mechanisms of fungicide resistance and DNA recombination and repair.

Models, Biological↗
PubMed2000

Potential of entomopathogenic nematodes for biological control of Acalymma vittatum (Coleoptera: Chrysomelidae) in cucumbers grown in conventional and organic soil management systems.

Acalymma vittatum (F.) is the primary insect pest of fresh-market cucumber and melon crops in much of the eastern United States because of their herbivory and interactions with several diseases, most notably bacterial wilt. A study was conducted to determine how soil management affects viability and infectivity of an entomopathogenic nematode that may be used for the control of A. vittatum. Dose-mortality curves under laboratory conditions suggested several Steinernema spp. as potential biocontrol agents. Field injections combined with soil bioassays showed that Steinernema riobravis Cabanillas, Poinar & Raulston (Rhabditus: Steinernematidae) longevity exceeded A. vittatum immature development time in both conventional and organic soil management systems. Mean root length densities of cucumbers increased in both soil management systems with the inclusion of nematodes. Soil management alone also influenced A. vittatum larval survivorship, with higher survival rates in the organic compared with the conventional soil management system. A 50% reduction in A. vittatum larval survival rates in both soil management systems, as determined by adult A. vittatum emergence, demonstrated the potential of incorporation of entomopathogenic nematodes for integrated pest management of diabroticites in commercial cucumber production.

Agriculture↗
PubMed1999

Molecular basis to understand polyploidy.

Polyploidy which is defined as an increase in chromosome number by an exact multiple of the haploid chromosome number is a typical characteristic of plant species but can also be found in almost all organisms from protists to humans. In the plant kingdom, since the reproduction can occur vegetatively, polyploid cells have time to settle down from the evolution point of view as a stable genetic system. So, 30 to 70% of angiosperms, including many important crop plants, are estimated to have polyploidy in their lineages. The success of polyploid species in plants has been attributed to their ability to colonise a wider range of habitats and to survive better in unstable climates compared with their diploid progenitors, presumably due to increased heterozygosity and flexibility provided by the presence of additional alleles.

Animals↗
PubMed2003

Evaluation of the genotoxic and teratogenic potential of a municipal sludge and sludge-amended soil using the amphibian Xenopus laevis and the tobacco: Nicotiana tabacum L. var. xanthi Dulieu.

The toxic, genotoxic and teratogenic potential of a municipal sewage sludge was assessed using the micronucleus assay on the larvae of the amphibian Xenopus laevis and with the tobacco somatic mutation test using the yellow-green xanthi Dulieu mutant a(1)(+)/a(1) a(2)(+)/a(2). The teratogenic potential was assessed by means of the Frog Embryo Teratogenesis Assay-Xenopus (FETAX). Various doses of the pasty sludge added to a crop soil were tested using the three bioassays. The test systems were performed either directly with sludge or sludge-amended soil samples (plant model) or with aqueous extracts (aquatic animal model). Using the tobacco model, we found no mutagenic impact of the soil amended with the sludge, perhaps because the clay-like nature of the soil, with its high adsorption capacity, may have prevented the contaminants from reaching the target. All leachates of amended soils produced a significant size reduction in Xenopus embryos. Depending on the soil/sludge ratio, some leachates were found to be genotoxic but were never teratogenic. This battery of in vivo test systems enabled us to estimate the global long-term effects under agricultural conditions with various genetic endpoints on ecologically relevant organisms characteristic of the aquatic and terrestrial compartments.

Absorption↗
PubMed1977

Urease activity in the digestive tract of the chick and its role in the utilisation of urea as a source of non-amino nitrogen.

Urease activity was found in caecal contents (about 10 mg urea metabolised/g h) and crop contents (about 0-5 mg urea metabolised/g h):there was very low activity in the contents of the colon but none in the rest of the digestive tract. 2. The urease activity of the crop contents was not bacterial in origin but the soyabean meal contained in the diet was found to have comparable activity. 3. Diets low in non-essential nitrogen and based on soyabean, fish meal or fish meal plus 0-2% jack bean urease, did not support higher growth rates when supplemented with urea. 4. The livers of chicks fed on the diet containing fish meal, urea and urease had significantly higher concentrations of free non-essential amino acids than those of chicks fed on the same diet but with urease excluded This suggested that dietary urease affects the availability of ammonia for the synthesis of non-essential amino acids but not for growth.

Amino Acids, Essential↗
PubMed2005

Influence of organically or conventionally produced wheat on health, performance and mycotoxin residues in tissues and bile of growing pigs.

From 1999-2001 three different varieties of wheat [Contur (susceptible to Fusarium), Batis and Petrus (less susceptible to Fusarium)] were cultivated under organic and conventional conditions in order to determine mycotoxin burden. Soil quality, preceding crop and weather conditions were comparable in the different production systems. The wheat batches were analysed for moulds, and the contents of zearalenone (ZEN) and deoxynivalenol (DON). Feeding trials were carried out with growing pigs (n = 96; average initial live weight 22.2 +/- 1.5 kg [mean +/- SD]) to examine a possible influence on the animal performance and on mycotoxin residues. The data recorded were clinical conditions, performance, biochemical and hematological data. Residues of ZEN, alpha- and beta-zearalenol (ZEL) and of DON were determined in bile, liver and muscle after slaughtering. Conventionally cultivated wheat was more frequently contaminated with Fusarium and contained more frequently ZEN and DON in higher concentrations than the organically produced wheat. Hematological and biochemical parameters of pigs fed with organically cultivated diets were not different from those of conventionally fed pigs. Pigs fed with organically produced wheat showed a slightly higher daily weight gain, but a lower carcass yield than the conventionally fed animals. The highest residues of DON and total-ZEN (ZEN + alpha-ZEL + beta-ZEL) were found in bile. Bile samples of organically fed pigs contained lower concentrations of total-ZEN than those of conventionally fed pigs. Altogether, these data suggest that wheat from an organic farming does not have higher mycotoxin-contamination than wheat from the conventional farming system.

Agriculture↗