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Hermann M. Niemeyer

Bio: Hermann M. Niemeyer is an academic researcher from University of Chile. The author has contributed to research in topics: Aphid & DIMBOA. The author has an hindex of 45, co-authored 289 publications receiving 7645 citations. Previous affiliations of Hermann M. Niemeyer include National Scientific and Technical Research Council & National University of Rosario.


Papers
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Journal ArticleDOI
TL;DR: Hydroxamic acids of the type 4-hydroxy-1,4-benzoxazin-3-ones constitute one of the most extensively studied secondary metabolites in relation to host plant resistance to pests and diseases.

618 citations

Journal ArticleDOI
TL;DR: Although the biosynthesis of benzoxazinoid hydroxamic acids has been elucidated, the genes and mechanisms controlling their differential expression in different plant tissues and along plant ontogeny remain to be unraveled.
Abstract: Many cereals accumulate hydroxamic acids derived from 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one. These benzoxazinoid hydroxamic acids are involved in defense of maize against various lepidopteran pests, most notably the European corn borer, in defense of cereals against various aphid species, and in allelopathy affecting the growth of weeds associated with rye and wheat crops. The role of benzoxazinoid hydroxamic acids in defense against fungal infection is less clear and seems to depend on the nature of the interactions at the plant-fungus interface. Efficient use of benzoxazinoid hydroxamic acids as resistance factors has been limited by the inability to selectively increase their levels at the plant growth stage and the plant tissues where they are mostly needed for a given pest. Although the biosynthesis of benzoxazinoid hydroxamic acids has been elucidated, the genes and mechanisms controlling their differential expression in different plant tissues and along plant ontogeny remain to be unraveled.

347 citations

Journal ArticleDOI
TL;DR: Hydroxamic acid concentration in Gramineae, both natural and incorporated, correlates with resistance to the aphid Metopolophium dirhodum, and it is proposed that hydroxamic acids act as naturally-occurring protective factors against M. Dirhodum.

168 citations

Journal ArticleDOI
TL;DR: It is proposed that the distribution of aphids on leaves of different ages is regulated by the hydroxamic acid content, which is always higher in the younger leaves.

130 citations


Cited by
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Journal ArticleDOI
TL;DR: It is concluded that host plant quality affects the fecundity of herbivorous insects at both the individual and the population scale.
Abstract: Host plant quality is a key determinant of the fecundity of herbivorous insects. Components of host plant quality (such as carbon, nitrogen, and defensive metabolites) directly affect potential and achieved herbivore fecundity. The responses of insect herbivores to changes in host plant quality vary within and between feeding guilds. Host plant quality also affects insect reproductive strategies: Egg size and quality, the allocation of resources to eggs, and the choice of oviposition sites may all be influenced by plant quality, as may egg or embryo resorption on poor-quality hosts. Many insect herbivores change the quality of their host plants, affecting both inter- and intraspecific interactions. Higher-trophic level interactions, such as the performance of predators and parasitoids, may also be affected by host plant quality. We conclude that host plant quality affects the fecundity of herbivorous insects at both the individual and the population scale.

1,962 citations

Journal ArticleDOI
TL;DR: The objectives of BIOS 781 are to present basic population and quantitative genetic principles, including classical genetics, chromosomal theory of inheritance, and meiotic recombination, and methods for genome-wide association and stratification control.
Abstract: LEARNING The objectives of BIOS 781 are to present: OBJECTIVES: 1. basic population and quantitative genetic principles, including classical genetics, chromosomal theory of inheritance, and meiotic recombination 2. an exposure to QTL mapping methods of complex quantitative traits and linkage methods to detect co-segregation with disease 3. methods for assessing marker-disease linkage disequilibrium, including case-control approaches 4. methods for genome-wide association and stratification control.

1,516 citations

Journal Article
TL;DR: The author wished to relate the three phases of research on insects and to express insect sociology as population biology in this detailed survey of knowledge of insect societies.
Abstract: In his introduction to this detailed survey of knowledge of insect societies, the author points out that research on insect sociology has proceeded in three phases, the natural history phase, the physiological phase and the population-biology phase. Advances in the first two phases have permitted embarkation in the third phase on a more rigorous theory of social evolution based on population genetics and writing this book, the author wished to relate the three phases of research on insects and to express insect sociology as population biology. A glossary of terms, a considerable bibliography and a general index are included. Other CABI sites 

1,394 citations

Book
01 Jan 2005
TL;DR: This work has shown clear trends in the dispersal and regeneration of seeds in disturbed areas, and these trends are likely to continue into the next decade.
Abstract: What determines the number and size of the seeds produced by a plant? How often should it reproduce them? How often should a plant produce them? Why and how are seeds dispersed, and what are the implications for the diversity and composition of vegetation? These are just some of the questions tackled in this wide-ranging review of the role of seeds in the ecology of plants. The authors bring together information on the ecological aspects of seed biology, starting with a consideration of reproductive strategies in seed plants and progressing through the life cycle, covering seed maturation, dispersal, storage in the soil, dormancy, germination, seedling establishment, and regeneration in the field. The text encompasses a wide range of concepts of general relevance to plant ecology, reflecting the central role that the study of seed ecology has played in elucidating many fundamental aspects of plant community function.

1,382 citations

Journal ArticleDOI
TL;DR: Differential expression of plant genes in response to closely related insect species suggest that some elicitors generated by phloem-feeding insects are species-specific and are dependent on the herbivore's developmental stage.
Abstract: Plant responses to herbivores are complex. Genes activated on herbivore attack are strongly correlated with the mode of herbivore feeding and the degree of tissue damage at the feeding site. Phloem-feeding whiteflies and aphids that produce little injury to plant foliage are perceived as pathogens and activate the salicylic acid (SA)-dependent and jasmonic acid (JA)/ethylene-dependent signaling pathways. Differential expression of plant genes in response to closely related insect species suggest that some elicitors generated by phloem-feeding insects are species-specific and are dependent on the herbivore's developmental stage. Other elicitors for defense-gene activation are likely to be more ubiquitous. Analogies to the pathogen-incompatible reactions are found. Chewing insects such as caterpillars and beetles and cell-content feeders such as mites and thrips cause more extensive tissue damage and activate wound-signaling pathways. Herbivore feeding is not equivalent to mechanical wounding. Wound responses are a part of the induced responses that accompany herbivore feeding. Herbivores induce direct defenses that interfere with herbivore feeding, growth and development, fecundity, and fertility. In addition, herbivores induce an array of volatiles that creates an indirect mechanism of defense. Volatile blends provide specific cues to attract herbivore parasites and predators to infested plants. The nature of the elicitors for volatile production is discussed.

1,309 citations