Genlisea aurea
Encyclopedia
Genlisea aurea is one of the largest carnivorous
species in the genus
Genlisea
(family Lentibulariaceae
). It has pale bundles of root-like organs up to about 15 cm long under ground that attract, trap, and digest protozoa
ns. These organs are subterranean leaves
, which lack chlorophyll
. G. aurea is endemic
to Brazil
, where it grows with several other species of Genlisea. It possesses the second smallest known genome
of any flowering plant
.
composed of nearly linear leaves about 2 mm wide. Leaves are typically 5-50 mm in length, but most of that length, including the petiole
, is hidden beneath the soil. The rosettes can grow to be as big as 5 cm wide. It has no true roots and instead has highly modified subterranean leaves that act as the carnivorous trapping mechanism.
The up to 40 cm tall inflorescence
produces one to three flowers at its apex that are typically 15-20 mm long and are the largest of the yellow-flowered species. Each inflorescence can produce up to a total of eleven flowers. In its natural habitat
, G. aurea can be found flowering year-round. The flowers and the scapes
are densely covered in glandular trichome
s.
The genome
s of several species in the genus Genlisea were studied in 2006. According to the study, prior to its publication the smallest known angiosperm (flowering plant) genome was that of Arabidopsis thaliana
at 157 Megabase pairs
(Mbp). With a diploid chromosome
number of around 52 (2n = ca.
52), G. aurea now holds the distinction of having the second smallest known angiosperm genome size
at 63.6 Mbp. The smallest individual chromatid
s from mitotic
anaphase
are just 2.1 Mbp and therefore have a size smaller than some bacterial chromosomes, such as the approximate 4 Mbp of Escherichia coli
. G. margaretae
has the smallest known angiosperm genome at 63.4 Mbp.
to Brazil
from the states of Mato Grosso
in the west to northeastern Bahia
and down to Santa Catarina
in the southeast. It typically grows on sandstone highlands at altitudes from 550 m to 2550 m. Its preferred substrate is a black humus-rich soil, which is sometimes mixed with sand. G. aurea lives among grasses in water-logged
seepages. The rosettes are usually submerged under water or produce a layer of mucilage
that remains in the cup formed by the dense rosette.
Of all other Genlisea species, G. pygmaea
is the most closely related when considering morphological characteristics. It differs slightly in habitat by preferring sandier soils and in morphology by possessing smaller flowers and fewer leaves.
that attracts, traps, kills, and digests prey, which are typically protozoans. Evidence of this behavior had been postulated ever since Charles Darwin
's time and has mostly relied on circumstantial findings of the occasional dead aquatic invertebrate in the utricle (digestion chamber). In 1975, however, British botanist Yolande Heslop-Harrison discovered digestive enzyme
activity in G. africana. Later, in 1998, Wilhelm Barthlott
and his colleagues concluded through experimentation that Genlisea attracts prey chemotactically
, traps them in the corkscrew "lobster pot" trap, digests them with enzymes produced by the plant, and then absorbs the nutrients. This study represented the first conclusive evidence that G. aurea was carnivorous.
in 1833 with four other Brazilian species. Darwin took note of G. aurea in his 1875 manuscript, Insectivorous Plants. Recent study has focused on the carnivorous nature of G. aurea. At least two published sources note the variety within the species and genus and are optimistic that additional species will be located.
Carnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...
species in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Genlisea
Genlisea
Genlisea is a genus of carnivorous plants also known as corkscrew plants. The 21 species grow in wet terrestrial to semi-aquatic environments distributed throughout Africa and Central and South America. The plants use highly modified underground leaves to attract, trap and digest minute...
(family Lentibulariaceae
Lentibulariaceae
Lentibulariaceae is a family of carnivorous plants containing three genera, Genlisea, the corkscrew plants, Pinguicula, the butterworts, and Utricularia, the bladderworts....
). It has pale bundles of root-like organs up to about 15 cm long under ground that attract, trap, and digest protozoa
Protozoa
Protozoa are a diverse group of single-cells eukaryotic organisms, many of which are motile. Throughout history, protozoa have been defined as single-cell protists with animal-like behavior, e.g., movement...
ns. These organs are subterranean leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
, which lack chlorophyll
Chlorophyll
Chlorophyll is a green pigment found in almost all plants, algae, and cyanobacteria. Its name is derived from the Greek words χλωρος, chloros and φύλλον, phyllon . Chlorophyll is an extremely important biomolecule, critical in photosynthesis, which allows plants to obtain energy from light...
. G. aurea is endemic
Endemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, where it grows with several other species of Genlisea. It possesses the second smallest known genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
of any flowering plant
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
.
Characteristics
G. aurea is a perennial herb that forms small, compact rosettesRosette (botany)
In botany, a rosette is a circular arrangement of leaves, with all the leaves at a single height.Though rosettes usually sit near the soil, their structure is an example of a modified stem.-Function:...
composed of nearly linear leaves about 2 mm wide. Leaves are typically 5-50 mm in length, but most of that length, including the petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...
, is hidden beneath the soil. The rosettes can grow to be as big as 5 cm wide. It has no true roots and instead has highly modified subterranean leaves that act as the carnivorous trapping mechanism.
The up to 40 cm tall inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
produces one to three flowers at its apex that are typically 15-20 mm long and are the largest of the yellow-flowered species. Each inflorescence can produce up to a total of eleven flowers. In its natural habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
, G. aurea can be found flowering year-round. The flowers and the scapes
Scape (botany)
In botany, scapes are leafless flowering stems that rise from the ground. Scapes can have a single flower or many flowers, depending on the species....
are densely covered in glandular trichome
Trichome
Trichomes are fine outgrowths or appendages on plants and certain protists. These are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae.- Algal trichomes :...
s.
The genome
Genome
In modern molecular biology and genetics, the genome is the entirety of an organism's hereditary information. It is encoded either in DNA or, for many types of virus, in RNA. The genome includes both the genes and the non-coding sequences of the DNA/RNA....
s of several species in the genus Genlisea were studied in 2006. According to the study, prior to its publication the smallest known angiosperm (flowering plant) genome was that of Arabidopsis thaliana
Arabidopsis thaliana
Arabidopsis thaliana is a small flowering plant native to Europe, Asia, and northwestern Africa. A spring annual with a relatively short life cycle, arabidopsis is popular as a model organism in plant biology and genetics...
at 157 Megabase pairs
Base pair
In molecular biology and genetics, the linking between two nitrogenous bases on opposite complementary DNA or certain types of RNA strands that are connected via hydrogen bonds is called a base pair...
(Mbp). With a diploid chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...
number of around 52 (2n = ca.
Circa
Circa , usually abbreviated c. or ca. , means "approximately" in the English language, usually referring to a date...
52), G. aurea now holds the distinction of having the second smallest known angiosperm genome size
Genome size
Genome size is the total amount of DNA contained within one copy of a single genome. It is typically measured in terms of mass in picograms or less frequently in Daltons or as the total number of nucleotide base pairs typically in megabases . One picogram equals 978 megabases...
at 63.6 Mbp. The smallest individual chromatid
Chromatid
A chromatid is one of the two identical copies of DNA making up a duplicated chromosome, which are joined at their centromeres, for the process of cell division . They are called sister chromatids so long as they are joined by the centromeres...
s from mitotic
Mitosis
Mitosis is the process by which a eukaryotic cell separates the chromosomes in its cell nucleus into two identical sets, in two separate nuclei. It is generally followed immediately by cytokinesis, which divides the nuclei, cytoplasm, organelles and cell membrane into two cells containing roughly...
anaphase
Anaphase
Anaphase, from the ancient Greek ἀνά and φάσις , is the stage of mitosis or meiosis when chromosomes move to opposite poles of the cell....
are just 2.1 Mbp and therefore have a size smaller than some bacterial chromosomes, such as the approximate 4 Mbp of Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
. G. margaretae
Genlisea margaretae
Genlisea margaretae is a carnivorous species in the genus Genlisea native to areas of Madagascar, Tanzania, and Zambia. It has pale bundles of root-like organs up to about 20 cm long under ground that attract, trap, and digest protozoans. These organs are subterranean leaves, which lack chlorophyll...
has the smallest known angiosperm genome at 63.4 Mbp.
Distribution and habitat
G. aurea is endemicEndemic (ecology)
Endemism is the ecological state of being unique to a defined geographic location, such as an island, nation or other defined zone, or habitat type; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, all species of lemur are endemic to the...
to Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
from the states of Mato Grosso
Mato Grosso
Mato Grosso is one of the states of Brazil, the third largest in area, located in the western part of the country.Neighboring states are Rondônia, Amazonas, Pará, Tocantins, Goiás and Mato Grosso do Sul. It also borders Bolivia to the southwest...
in the west to northeastern Bahia
Bahia
Bahia is one of the 26 states of Brazil, and is located in the northeastern part of the country on the Atlantic coast. It is the fourth most populous Brazilian state after São Paulo, Minas Gerais and Rio de Janeiro, and the fifth-largest in size...
and down to Santa Catarina
Santa Catarina (state)
Santa Catarina is a state in southern Brazil with one of the highest standards of living in Latin America. Its capital is Florianópolis, which mostly lies on the Santa Catarina Island. Neighbouring states are Rio Grande do Sul to the south and Paraná to the north. It is bounded on the east by...
in the southeast. It typically grows on sandstone highlands at altitudes from 550 m to 2550 m. Its preferred substrate is a black humus-rich soil, which is sometimes mixed with sand. G. aurea lives among grasses in water-logged
Waterlogging
Waterlogging or water logging may refer to:* Waterlogging , saturation of the soil by groundwater sufficient to prevent or hinder agriculture...
seepages. The rosettes are usually submerged under water or produce a layer of mucilage
Mucilage
Mucilage is a thick, gluey substance produced by most plants and some microorganisms. It is a polar glycoprotein and an exopolysaccharide.It occurs in various parts of nearly all classes of plant, usually in relatively small percentages, and is frequently associated with other substances, such as...
that remains in the cup formed by the dense rosette.
Of all other Genlisea species, G. pygmaea
Genlisea pygmaea
Genlisea pygmaea is a corkscrew plant native to South America....
is the most closely related when considering morphological characteristics. It differs slightly in habitat by preferring sandier soils and in morphology by possessing smaller flowers and fewer leaves.
Carnivory
G. aurea, like all Genlisea species, is a carnivorous plantCarnivorous plant
Carnivorous plants are plants that derive some or most of their nutrients from trapping and consuming animals or protozoans, typically insects and other arthropods. Carnivorous plants appear adapted to grow in places where the soil is thin or poor in nutrients, especially nitrogen, such as acidic...
that attracts, traps, kills, and digests prey, which are typically protozoans. Evidence of this behavior had been postulated ever since Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
's time and has mostly relied on circumstantial findings of the occasional dead aquatic invertebrate in the utricle (digestion chamber). In 1975, however, British botanist Yolande Heslop-Harrison discovered digestive enzyme
Digestive enzyme
'Digestive enzymes' are enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption by the body. Digestive enzymes are found in the digestive tract of animals where they aid in the digestion of food as well as inside the cells,...
activity in G. africana. Later, in 1998, Wilhelm Barthlott
Wilhelm Barthlott
Wilhelm Barthlott is German botanist and the head of the Nees-Institute for Biodiversity of Plants and director of the Botanical Gardens of the University of Bonn.- External links :*...
and his colleagues concluded through experimentation that Genlisea attracts prey chemotactically
Chemotaxis
Chemotaxis is the phenomenon in which somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment. This is important for bacteria to find food by swimming towards the highest concentration of food molecules,...
, traps them in the corkscrew "lobster pot" trap, digests them with enzymes produced by the plant, and then absorbs the nutrients. This study represented the first conclusive evidence that G. aurea was carnivorous.
Botanical history
G. aurea was initially discovered and described by Augustin Saint-HilaireAugustin Saint-Hilaire
Augustin François César Prouvençal de Saint-Hilaire , French botanist and traveler, was born at Orléans, France, on 4 October 1779. He began to publish memoirs on botanical subjects at an early age...
in 1833 with four other Brazilian species. Darwin took note of G. aurea in his 1875 manuscript, Insectivorous Plants. Recent study has focused on the carnivorous nature of G. aurea. At least two published sources note the variety within the species and genus and are optimistic that additional species will be located.