Jasmonic acid
Encyclopedia
Jasmonic acid is derived from the fatty acid linolenic acid. It is a member of the jasmonate
class of plant hormone
s. It is biosynthesized from linolenic acid by the octadecanoid pathway
.
The major function of JA and its various metabolites is regulating plant responses to abiotic and biotic stresses as well as plant growth and development. Regulated plant growth and development processes include growth inhibition, senescence
, tendril
coiling, flower development and leaf abscission. JA is also responsible for tuber
formation in potatoes, yams, and onions. It has an important role in response to wounding of plants and systemic acquired resistance
. When plants are attacked by insects, they respond by releasing JA, which activates the expression of protease inhibitors
, among many other anti-herbivore defense compounds. These protease inhibitors prevent proteolytic activity of the insects' digestive proteases, thereby stopping them from acquiring the needed nitrogen in the protein
for their own growth.
Jasmonic acid is also converted to a variety of derivatives including ester
s such as methyl jasmonate; it may also be conjugated to amino acids.
This chemical may have a role in pest control, according to an October 2008 BBC News report. In addition, researchers at the UK's Lancaster University have signed a licensing deal with an American company to market jasmonic acid as a spray to be applied to seeds prior to planting; such a spray has been found to stimulate the natural anti-pest defenses of the plants that germinate from the sprayed seeds, without harming plant growth as happens when the acid is sprayed on plants that have already started growing.
Jasmonate
Jasmonate and its derivatives are lipid-based hormone signals that regulate a wide range of processes in plants, ranging from growth and photosynthesis to reproductive development. In particular, JAs are critical for plant defense against herbivory and plant responses to poor environmental...
class of plant hormone
Plant hormone
Plant hormones are chemicals that regulate plant growth, which, in the UK, are termed 'plant growth substances'. Plant hormones are signal molecules produced within the plant, and occur in extremely low concentrations. Hormones regulate cellular processes in targeted cells locally and, when moved...
s. It is biosynthesized from linolenic acid by the octadecanoid pathway
Octadecanoid pathway
The octadecanoid pathway is a reasonably well-characterized biosynthetic pathway for the production of the phytohormone jasmonic acid , an important hormone for induction of defense genes. JA is synthesized from alpha-linolenic acid, which can be released from the plasma membrane by certain lipase...
.
The major function of JA and its various metabolites is regulating plant responses to abiotic and biotic stresses as well as plant growth and development. Regulated plant growth and development processes include growth inhibition, senescence
Senescence
Senescence or biological aging is the change in the biology of an organism as it ages after its maturity. Such changes range from those affecting its cells and their function to those affecting the whole organism...
, tendril
Tendril
In botany, a tendril is a specialized stem, leaf or petiole with a threadlike shape that is used by climbing plants for support, attachment and cellular invasion by parasitic plants, generally by twining around suitable hosts. They do not have a lamina or blade, but they can photosynthesize...
coiling, flower development and leaf abscission. JA is also responsible for tuber
Tuber
Tubers are various types of modified plant structures that are enlarged to store nutrients. They are used by plants to survive the winter or dry months and provide energy and nutrients for regrowth during the next growing season and they are a means of asexual reproduction...
formation in potatoes, yams, and onions. It has an important role in response to wounding of plants and systemic acquired resistance
Systemic acquired resistance
The systemic acquired resistance is a "whole-plant" resistance response that occurs following an earlier localized exposure to a pathogen. SAR is analogous to the innate immune system found in animals, and there is evidence that SAR in plants and innate immunity in animals may be evolutionarily...
. When plants are attacked by insects, they respond by releasing JA, which activates the expression of protease inhibitors
Protease inhibitor (biology)
In biology and biochemistry, protease inhibitors are molecules that inhibit the function of proteases. Many naturally occurring protease inhibitors are proteins....
, among many other anti-herbivore defense compounds. These protease inhibitors prevent proteolytic activity of the insects' digestive proteases, thereby stopping them from acquiring the needed nitrogen in the protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
for their own growth.
Jasmonic acid is also converted to a variety of derivatives including ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
s such as methyl jasmonate; it may also be conjugated to amino acids.
This chemical may have a role in pest control, according to an October 2008 BBC News report. In addition, researchers at the UK's Lancaster University have signed a licensing deal with an American company to market jasmonic acid as a spray to be applied to seeds prior to planting; such a spray has been found to stimulate the natural anti-pest defenses of the plants that germinate from the sprayed seeds, without harming plant growth as happens when the acid is sprayed on plants that have already started growing.