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1.
The population dynamics of Heterodera glycines as influenced by alachlor, fenamiphos, and ethoprop alone and in herbicide-nematicide combinations were studied in the field. Numbers of H. glycines juveniles and eggs were higher at midseason and harvest where nematicides were applied. Fenamiphos alone or in combination with alachlor provided better control of H. glycines and greater seed yields than treatments with ethoprop. Numbers of H. glycines eggs at harvest in 1980 were positively correlated with numbers of juveniles at planting in 1981 and negatively related to seed yield in 1981. 相似文献
2.
The infectivity and development of four populations of Meloidogyne hapla were compared, at three temperatures, on tomato and two varieties of cucumber. A population from Canada produced few root-galls on cucumber and, except at 24 C, no larvae developed into adult females and produced egg masses. In contrast, a population with 45 chromosomes from America produced many galls on cucumber and small proportions of larvae became females and produced egg masses at 20 and 24 C. At 18 C this population produced no egg masses on cucumber, but a population from Britain and one from America with 17 chromosomes produced more egg masses at this temperature than at 20 or 24 C. Dissection of the galls showed that on cucumber many larvae died or their growth and development was slowed. 相似文献
3.
Glycoalkaloids were used as evidence of the affinities of nine taxa of Solanum Series Megistacrolobum and related potato cultigens from western Bolivia. S. boliviense, S. sanctae-rosae and S. toralapanum contain the commertetraose sugar moiety and appear to represent a relatively wild group within the Series. S. megistacrolobum, S. sogarandinum and S. raphanifolium show anomolous glycoalkaloid profiles that probably reflect hybridization associated with human disturbance. Primitive forms of the S. χ ajanhuiri cultigen are indistinguishable chemicaliy from conspecific weeds that were previously classified as S. megistacrolobum. Variation in total glycoalkaloid content within Series Megistacrolobum likely reflects direct selection by humans for reduced glycoalkaloid levels during the domestication process. 相似文献
4.
《Molecular & cellular proteomics : MCP》2023,22(2):100490
Aspergillus flavus is a common saprophytic and pathogenic fungus, and its secondary metabolic pathways are one of the most highly characterized owing to its aflatoxin (AF) metabolite affecting global economic crops and human health. Different natural environments can cause significant variations in AF synthesis. Succinylation was recently identified as one of the most critical regulatory post-translational modifications affecting metabolic pathways. It is primarily reported in human cells and bacteria with few studies on fungi. Proteomic quantification of lysine succinylation (Ksuc) exploring its potential involvement in secondary metabolism regulation (including AF production) has not been performed under natural conditions in A. flavus. In this study, a quantification method was performed based on tandem mass tag labeling and antibody-based affinity enrichment of succinylated peptides via high accuracy nano-liquid chromatography with tandem mass spectrometry to explore the succinylation mechanism affecting the pathogenicity of naturally isolated A. flavus strains with varying toxin production. Altogether, 1240 Ksuc sites in 768 proteins were identified with 1103 sites in 685 proteins quantified. Comparing succinylated protein levels between high and low AF-producing A. flavus strains, bioinformatics analysis indicated that most succinylated proteins located in the AF biosynthetic pathway were downregulated, which directly affected AF synthesis. Versicolorin B synthase is a key catalytic enzyme for heterochrome B synthesis during AF synthesis. Site-directed mutagenesis and biochemical studies revealed that versicolorin B synthase succinylation is an important regulatory mechanism affecting sclerotia development and AF biosynthesis in A. flavus. In summary, our quantitative study of the lysine succinylome in high/low AF-producing strains revealed the role of Ksuc in regulating AF biosynthesis. We revealed novel insights into the metabolism of AF biosynthesis using naturally isolated A. flavus strains and identified a rich source of metabolism-related enzymes regulated by succinylation. 相似文献
5.
The sex ratio of the Arkansas 1 isolate of Heterodera glycines was determined in experiments in which ''Lee'' soybean was inoculated with either one or two larvae. A 3:1 male to female sex ratio was established for this isolate under the test conditions used. No influence of one nematode on the penetration and development to adult of another nematode in the same root was detected in double larval inoculations. 相似文献
6.
Changes in gene expression that occur in the stolon tips of potato ( Solanum tuberosum L.) cv. Record during tuberisation were investigated. Protein extracts from stolon tips at various stages in the tuberisation process were analysed by two-dimensional gel electrophoresis. A number of quantitative and qualitative changes in polypeptide composition accompanied the very early stages of tuberisation. In vitro translation of RNA extracted from stolon tips also revealed quantitative and qualitative changes associated with tuberisation. Immunoblotting of protein extracts with monoclonal antibodies raised against α- and β-tubulin showed quantitative changes in the relative level of β-tubulin, but not α-tubulin, as the stolon tips tuberised. Changes in the pattern of α-tubulin isotype expression were shown to occur at early stages in the tuberisation process. 相似文献
7.
ALAIN THIÉRY NICOLAS RABET GABRIEL NÈVE 《Biological journal of the Linnean Society. Linnean Society of London》2007,90(1):55-60
The shape of the resting eggs of a large branchiopod crustacean, the Anostraca Tanymastix stagnalis , is represented very accurately by analytical expressions. The occurrence of atypical shape of some T. stagnalis eggs may be viewed as a simple change of the analytical expression describing the usual egg shape. Their unusual shape may be explained by a higher embryo volume within an envelope of a given size. Biological implications are briefly discussed and hypothesized in an evolutionary point of view. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 55–60. 相似文献
8.
Differences in microhabitat,abundance, biomass and body size between oxybiotic and thiobiotic free-living marine nematodes 总被引:1,自引:0,他引:1
P. Jensen 《Oecologia》1987,71(4):564-567
Summary Analysis of samples from a 15 m deep sandy bottom in the northern part of Øresund, Denmark shows that the nematode fauna comprises 2.9 million individuals per m2 down to 20 cm depth which averages of 0.40 g organic carbon. Highest densities are found in the uppermost cm. Biomass attains its highest value at 1–2 cm depth. Three results are discussed: 1) nematodes in the uppermost cm are, on average, three times smaller than those between 1–8 cm depth (60 ng org. C vs. 200 ng org. C ind. weight); 2) a distinct abundance trough is found at 8 cm depth, which correlates with the physical space occupied by the gallery of the lugworm Arenicola marina as well as with its possibly unselective feeding on the interstitial meiofauna at that depth; 3) the thiobiotic (deeper-living) species are significantly more slender than the oxybiotic (surface-dwelling) species, suggesting surface-dependent adaptations to life in oxygen poor and sulphide rich sediments where large amounts of dissolved organic matter occur. This is in contrast to previous assumptions that the body length or body shape reflects adaptations to the physical constraints of interstitial space. 相似文献
9.
N. Pallais 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1987,73(6):784-792
Summary Environmental influence on physiological factors that determine seed quality is discussed in relation to true potato seed (TPS). This review has been motivated by the need for high quality seed for the proper evaluation of TPS technology. The objectives of tuber production may not be in harmony with those required for the production of high quality TPS. The production of high quality TPS may be influenced by the stronger sink strength ability of fast developing tubers for assimilation of available nutrients. Earliness of tuber formation, which is needed in TPS progenitors, may tend to result in incomplete TPS development. Limiting conditions during seed development decrease the potential of the seed for field establishment. Seed vigor is the most important attribute of seed quality since it is essential for seedling performance under the adverse conditions commonly encountered during field development. The attractiveness of TPS technology for tropical areas, where potato production is limited by low-quality seed tuber availability, is decreased by the lack of seedling vigor and uniformity of seedlings derived from TPS. Current research indicates that considerable genetic improvement of TPS vigor and uniformity is possible. It is suggested that significant immediate improvement of TPS quality would result from agronomic techniques that reflect understanding of the physiological factors that influence the production and maintenance of high quality seed. Research areas needed to develop methodologies for TPS production with optimum expression of genotype are identified.Abbreviations TPS
True potato seed
- CIP
International Potato Center, Lima, Peru
- SD
Short day
- LD
Long day
- INIA
Instituto Nacional de Investigaciones Agropecuarias, Chile
- GA
Gibberellic acid 相似文献
10.
R. D. Riggs 《Journal of nematology》1987,19(2):251-254
A total of 66 plants in 50 species were inoculated with eggs and juveniles of soybean cyst nematode, Heterodera glycines. Roots were stained and observed for penetration and development of the nematode. Twenty-six plants were not penetrated; twenty-three were penetrated, but there was no development of the nematode; eight were penetrated with some nematode development; two were penetrated and had considerable nematode development, but few nematodes, if any, matured; and seven were penetrated with many nematodes maturing. The penetration of nonhosts may imply some susceptibility and that populations eventually would build up on the penetrated plants. Plants not penetrated may be useful as rotation plants because no reproduction would occur. 相似文献