Paula McSteen | |
|---|---|
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| Alma mater | University of East Anglia |
| Scientific career | |
| Institutions | University of Missouri |
| Thesis | Genetic interactions controlling perianth development in Antirrhinum majus (1996) |
Paula McSteen is a scientist known for her research on plant genetics. In 2020 she was elected a fellow of the American Association for the Advancement of Science.
McSteen received her B.A. from the University of Dublin Trinity College and earned her Ph.D. in Plant Developmental Genetics in 1996 from the University of East Anglia. [1] In 2010 she joined the faculty of the University of Missouri as an associate professor, [2] having previously worked as an assistant professor at Pennsylvania State University. As of 2021 she is a professor at the University of Missouri. [1]
McSteen is known for her research on plant genetics, particularly on the role of hormones that influence the actions of plant meristems. Her graduate research defined the genes required to control the development of reproductive organs in Antirrhinum, flowers commonly known as snapdragons. [3] [4] She then moved to using corn as a genetic model. She has examined the role of multiple genes by corn, including research into bif2 barren inflorescence2 which plays a role in regulation of hormones needed during the development of corn. [5] [6] Through examination of corn that produced malformed ears, McSteen determined that the gene vt2, short for vanishing tassel2, was absent, [7] which means reduced levels of the hormone auxin and leads to malformed ears of corn. [8] In 2019, McSteen found the barren stalk2 gene, ba2, which impacts the development of the cells that give rise to ears of corn. [9] [10] In the course of learning about this gene, she found that this mutation had first been found in the 1930s, but then knowledge about its role was lost. [11]
In cell biology, the meristem is a type of tissue found in plants. It consists of undifferentiated cells capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells continue to divide until they become differentiated and lose the ability to divide.
Plant hormones are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, including embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and reproductive development. Unlike in animals each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book.
Vegetative reproduction is a form of asexual reproduction occurring in plants in which a new plant grows from a fragment or cutting of the parent plant or specialized reproductive structures, which are sometimes called vegetative propagules.
Auxins are a class of plant hormones with some morphogen-like characteristics. Auxins play a cardinal role in coordination of many growth and behavioral processes in plant life cycles and are essential for plant body development. The Dutch biologist Frits Warmolt Went first described auxins and their role in plant growth in the 1920s. Kenneth V. Thimann became the first to isolate one of these phytohormones and to determine its chemical structure as indole-3-acetic acid (IAA). Went and Thimann co-authored a book on plant hormones, Phytohormones, in 1937.
Gibberellins (GAs) are plant hormones that regulate various developmental processes, including stem elongation, germination, dormancy, flowering, flower development, and leaf and fruit senescence. GAs are one of the longest-known classes of plant hormone. It is thought that the selective breeding of crop strains that were deficient in GA synthesis was one of the key drivers of the "green revolution" in the 1960s, a revolution that is credited to have saved over a billion lives worldwide.
Plant embryonic development, also plant embryogenesis, is a process that occurs after the fertilization of an ovule to produce a fully developed plant embryo. This is a pertinent stage in the plant life cycle that is followed by dormancy and germination. The zygote produced after fertilization must undergo various cellular divisions and differentiations to become a mature embryo. An end stage embryo has five major components including the shoot apical meristem, hypocotyl, root meristem, root cap, and cotyledons. Unlike the embryonic development in animals, and specifically in humans, plant embryonic development results in an immature form of the plant, lacking most structures like leaves, stems, and reproductive structures. However, both plants and animals including humans, pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification.
Gravitropism is a coordinated process of differential growth by a plant in response to gravity pulling on it. It also occurs in fungi. Gravity can be either "artificial gravity" or natural gravity. It is a general feature of all higher and many lower plants as well as other organisms. Charles Darwin was one of the first to scientifically document that roots show positive gravitropism and stems show negative gravitropism. That is, roots grow in the direction of gravitational pull and stems grow in the opposite direction. This behavior can be easily demonstrated with any potted plant. When laid onto its side, the growing parts of the stem begin to display negative gravitropism, growing upwards. Herbaceous (non-woody) stems are capable of a degree of actual bending, but most of the redirected movement occurs as a consequence of root or stem growth outside. The mechanism is based on the Cholodny–Went model which was proposed in 1927, and has since been modified. Although the model has been criticized and continues to be refined, it has largely stood the test of time.
Marcus Morton Rhoades was an American cytogeneticist.
The ABC model of flower development is a scientific model of the process by which flowering plants produce a pattern of gene expression in meristems that leads to the appearance of an organ oriented towards sexual reproduction, a flower. There are three physiological developments that must occur in order for this to take place: firstly, the plant must pass from sexual immaturity into a sexually mature state ; secondly, the transformation of the apical meristem's function from a vegetative meristem into a floral meristem or inflorescence; and finally the growth of the flower's individual organs. The latter phase has been modelled using the ABC model, which aims to describe the biological basis of the process from the perspective of molecular and developmental genetics.
A primordium in embryology, is an organ or tissue in its earliest recognizable stage of development. Cells of the primordium are called primordial cells. A primordium is the simplest set of cells capable of triggering growth of the would-be organ and the initial foundation from which an organ is able to grow. In flowering plants, a floral primordium gives rise to a flower.
Lateral roots, emerging from the pericycle, extend horizontally from the primary root (radicle) and over time makeup the iconic branching pattern of root systems. They contribute to anchoring the plant securely into the soil, increasing water uptake, and facilitate the extraction of nutrients required for the growth and development of the plant. Lateral roots increase the surface area of a plant's root system and can be found in great abundance in several plant species. In some cases, lateral roots have been found to form symbiotic relationships with rhizobia (bacteria) and mycorrhizae (fungi) found in the soil, to further increase surface area and increase nutrient uptake.
DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) is a naturally occurring hydroxamic acid, a benzoxazinoid. DIMBOA is a powerful antibiotic present in maize, wheat, rye, and related grasses,
Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant always has embryonic tissues. By contrast, an animal embryo will very early produce all of the body parts that it will ever have in its life. When the animal is born, it has all its body parts and from that point will only grow larger and more mature. However, both plants and animals pass through a phylotypic stage that evolved independently and that causes a developmental constraint limiting morphological diversification.
In molecular biology, the auxin binding protein family is a family of proteins which bind the plant hormone auxin. They are located in the lumen of the endoplasmic reticulum (ER). The primary structure of these proteins contains an N-terminal hydrophobic leader sequence of 30-40 amino acids, which could represent a signal for translocation of the protein to the ER. The mature protein comprises around 165 residues, and contains a number of potential N-glycosylation sites. In vitro transport studies have demonstrated co-translational glycosylation. Retention within the lumen of the ER correlates with an additional signal located at the C terminus, represented by the sequence Lys-Asp-Glu-Leu, known to be responsible for preventing secretion of proteins from the lumen of the ER in eukaryotic cells.
Vegetative phase change is the juvenile-to-adult transition in plants. This transition is distinct from the reproductive transition and is most prolonged and pronounced in woody species. Manipulating phase change may be an important avenue for plant improvement.
L-tryptophan—pyruvate aminotransferase is an enzyme with systematic name L-tryptophan:pyruvate aminotransferase. This enzyme catalyses the following chemical reaction
Heteroblasty is the significant and abrupt change in form and function, that occurs over the lifespan of certain plants. Characteristics affected include internode length and stem structure as well as leaf form, size and arrangement. It should not be confused with seasonal heterophylly, where early and late growth in a season are visibly different. This change is different from a homoblastic change which is a gradual change or little change at all, so that there is little difference between the juvenile and adult stages. Some characteristics affected by heteroblastic change include the distance between successive leaves and stem structure as well as leaf form, size and arrangement. Heteroblasty is found in many plant families as well as only some species within a genus. This random spread of heteroblastic plants across species is believed to be caused by convergent evolution.
Not to be confused with Rosemary Carpenter Fitzgerald.
Sarah Hake is an American plant developmental biologist who directs the USDA's Plant Gene Expression Center in Albany, CA. In 2009 she was elected a fellow of the American Association for the Advancement of Science and elected member of the National Academy of Sciences.