AMINO ACIDS Description of Amino acids and their functions in plants

Transcription

1 AMINO ACIDS Description of Amino acids and their functions in plants

2 Technical Report 1. Introduction... 3 Proteic amino acids... 5 Amino acids in plants Amino acids functions Aliphatic... 6 Acids Basics Hydroxylic Sulfur-containing Amidic Conclusions ARTAL Solutions Aminotal Super Vegeamino... 22

3 1. Introduction Amino acids are organic molecules composed by Carbon, Hydrogen, Oxygen and Nitrogen. Their components are grouped into 3 major groups: a carboxylic acid (-COOH), an amino group (-NH2) and a lateral chain (-R). We can find two classes of amino acids inside a living being: a) Proteic amino acids: These amino acids do their function by aggregating themselves to other amino acids, making the molecules known as proteins. Proteins play an essential role in every metabolic pathway and in every structural part of the body. They are the bricks of which the body of the organism is made (structural proteins), as well as the motor that make the metabolism work properly (enzymes).

4 b) Non-proteic amino acids: These amino acids are not part of any proteins. They do their function by themselves, not by creating complexes with other amino acids. All the proteic amino acids, when they realize a function by themselves, are examples of non-proteic amino acids but there are more kinds of non-proteic amino acids that are not included in the list of the proteic ones. Examples of these amino acids are hydroxyproline, ornithine, mimosine, canavanine Furthermore, we can find to types of amino acids depending on the orientation of the amine group (-NH2) in the molecule. The pair of identical molecules with only this difference between them both are called enantiomers. When we find the amino group on the right, we call it D-enantiomer and when it is on the left we call it L-enantiomer. L-enantiomer D-enantiomer

5 Proteic amino acids We can find up to 20 different types of proteic amino acids inside a living being, all in the L-form enantiomer. The difference between the 20 proteic amino acids is the composition of the lateral chain. Depending of the lateral chain we can find: Alanine (ala), arginine (arg), aspargine (asn), aspartic acid (asp), cysteine (cys), glutamine (gln), glutamic acid (glu), glycine (gly), histidine (his), isoleucine (ile), leucine (leu), lysine (lys), methionine (met), phenylalanine (phe), proline (pro), serine (ser), threonine (thr), tryptophan (trp), tyrosine (tyr), valine (val). These amino acids are grouped due to the chemical properties of their lateral chain. Aliphatic (no cyclic lateral chain) - alanine, glycine, isoleucine, leucine, proline, valine. Aromatic (cyclic lateral chain) phenylalanine, tryptophan, tyrosine. Acidic - aspartic acid glutamic acid. Basic arginine, histidine, lysine. Hydroxylic (with an OH group in the lateral chain) - serine, threonine. Sulphur-containing (-SH group in the lateral chain) - cysteine, methionine. Amidic (containing amide group -NH2 in the side chain) asparagine, glutamine.

6 Amino acids in plants Plants are able to synthetize their own amino acids through five pathways, named after the precursor of the pathway. We can find: a) Pyruvate family: Alanine, valine and leucine are synthetized through this pathway. b) Oxaloacetate family: Aspartic acid/asparagine, lysine, threonine, methionine and isoleucine. c) Alfa-cetoglutarate family: Glutamic acid/glutamine, proline, hidroxy proline and arginine. d) Shikimate family: Tyrosine, phenylalanine, tryptophan and histidine. e) Calvin cycle family: Glycine, serine and cysteine. Animals cannot synthetize phenylalanine, histidine, tryptophan, valine, leucine, isoleucine, methionine and threonine. They are called essential amino acids and animals need to ingest them through a vegetal diet in order to dispose of them in the body. 2. Amino acids functions. Aliphatic Alanine Accumulated under anoxia, helps the production of ATP when the floor is waterlogged and no oxygen is available to create ATP, which is the main source of energy that the plant use to do its chemical reactions. Extra alanine helps the plant survive this kind of stress. Increases the Nitrogen uptake so less Nitrogen is required when fertilization has to be done.

7 Glycine This amino acid plays various serious roles when it forms part of proteins. There is a family composed by all the proteins who have high presence of this amino acid within them, known as Glycine Rich Proteins (GRP) which take part in many processes: a) They are implicated in the formation of the cell wall, leading to a better disposal of the structural tissue of the plant. b) Also GRP play a role in the defense against some diseases like the turnip vein-clearing tobamovirus. This is because Glycine plays a role in the deposition of callose, which impedes the movements of the viruses and diseases through the conductive system of the plant. c) This family plays a very important role in reproduction. It is a key element on the hydration of the pollen, process that allows the pollen to enter inside the ovaries. d) They are highly expressed in the stoma guard cells, where helps the regulation of the opening and closure if the stoma to prevent water loss when heat stress conditions occurs. e) They seem to play a role in cold shock adaptation of plants.

8 Isoleucine Together with valine, leucine and isoleucine they form the branched-chain amino acids, which play an important role in structural proteins. Also this amino acid plays a major role in the root development. Lack of this amino acids will shorten the roots drastically. Leucine Leucine is located in large quantities in a kind of proteins called Leucine- Rich Repeat Receptor Kinases, a family of protein placed in the cell wall with that trigger lots of important processes for the cell, like cell proliferation, stem cell maintenance, hormone perception, host-specific as well as non-hostspecific defense response, wounding response, and symbiosis with mycorhizes.

9 The functions of this amino acid are numerous, so a high disposal of this amino acid will help the plant grow fast and healthy. Proline It acts as a compatible solute. A compatible solute is a small solute, dissolved in the cellular matrix, who avoid osmotic imbalance. Osmosis works like this: When you have a liquid with a semipermeable membrane (this is, water can pass through it but not the solutes dissolved in the water) the water is compartmented in two zones. The osmotic pressure makes the water goes through the membrane to the zone where the solute concentration is higher to compensate the excess of solutes and to maintain an osmotic equilibrium. A compatible solute, proline in this case, helps the cell keeping water inside of it when hydric stress occur. When no water is available in the soil, and the concentration of solutes is high in it, water tends to leave the cell because the osmotic pressure. Proline increases the quantity of solutes inside the cell,

10 balancing the inner concentration and the outer concentration, balancing the osmotic pressure and keeping the water inside the cells. Also a compatible solute helps when low temperatures occur. The water freezes at lower temperatures when it has high concentration of solutes in it. The cell matrix is full of water and if it freezes, water crystals are formed damaging the cell structure like a knife. Solved Proline helps this freeze temperature to be lower, and it impedes the ice crystals not to be formed, and to avoid this damage produced by them. Proline also diminishes the oxidative effect of oxygen free radicals. It stabilizes the anti-oxidant proteins in the cell matrix making them live longer and increasing their activity. Proline play a key role in the plant response to all kinds of stress but also has been shown that the addition of proline helps the set of some fruits, like apples. Valine It has been found no specific functions of this amino acid beyond forming part of proteins.

11 Aromatics Phenylalanine L-Phenylalanine is the main precursor of the phenylpropanoid compounds that play key roles in the plant. This compounds are synthetized by the enzyme Phenylalanine ammonia lyase and they have several functions: a) They help the plant to deal with biotic stresses. These compounds accumulate in wounded or infected areas, damaged by herbivores or fungus, insects Some of these compounds are also toxics for herbivores. Also lignin is a derived compound of this phenylpropanoids, and is the compound that makes the wood, hardening the plant and reducing the damage that herbivores can cause to it. b) They help the plant to deal with abiotic stresses. Flavonoids and isoflavonoids, both derived from phenylpropanoid, reduce the harmful effect of the UV light to the plant. Also they absorb light when high insolation occurs, because photosynthesis reduces its efficiency with high light intensity.

12 This compounds can t be synthetized when there is a lack of phenylalanine, so a good supply of this amino acid is key for a good grow of the plant. Tryptophan This amino acid is the precursor of auxins (indol-3-acetic acid), process made by the plant naturally just with a 2-steps biochemical pathway. Auxins are a group of hormones involved in the plant s growth, especially in the formation of roots and cell elongation. They also delay foliar senescence. Because of this, tryptophan is needed for the plant to grow properly, especially when vegetative growth occurs. Tyrosine Tyrosine is the precursor of the catecholamines. These compounds are relative well known, adrenaline, noradrenaline and dopamine are part of this family of compounds. In plants they stimulate in some cases the growth of the

13 plant indirectly. Dopamine stimulate the production of ethylene in some plants, and this ethylene is the compound that stimulates the growth and the fruit ripening. Acids Aspartic acid The function of this amino acid is to be part of proteins and also it is the metabolic substrate from which lysine, threonine, methionine and isoleucine are produced. Also it acts as a substrate for the Krebs cycle, which is the one of the main producer of energetic metabolites. Glutamic acid In its ionized form, glutamate, it serves as the first organic form in which inorganic Nitrogen (ammonia) is fixed. Furthermore, this amino acid serves of Nitrogen donor for the biosynthesis of all the amino acids. This amino acid has roles for itself. It is important for the pollination: it increases the pollen germination and the length of the pollinic tube, key for the fertilization of the ovule.

14 Also it is the substrate for the formation of proline, hidroxy proline and arginine. Arginine Basics Arginine is the main source of nitrogen reservoir and also recycles the nitrogen. One of its functions is to distribute Nitrogen all over the plant. This amino acid is the substrate for the production of Nitric Oxide. Nitric oxide is a compound that plays several roles in the plant: a) Acts as part of the infection-resistance systems. b) Helps the mycorrhization process to be stablished in the plant. This process is a symbiosis (win-win relationship) between the plant and a beneficial fungus that is set in the plant s roots. c) Serves as initiator for the root development and the development of lateral roots. Auxins are also implicated in this process. d) Regulates aperture/closure of the stomata, epidermic holes in the leaves who open and closes depending on the outer temperature. If the temperature is high the stomata close to avoid losing water through these holes, but if the temperature is not high the stomata are open to allow gaseous exchange from the inside of the plant to the atmosphere. Also polyamides are synthetized from Arginine as well. The plant s representatives of these element are putrescine, spermidine and spermine. Polyamides are hormone-like compounds that modulate several processes:

15 a) Cell division. b) Dormancy breaking of tubers and germination of seeds, c) Stimulation, support and development of flower buds d) Embryogenesis, fruit set fruit ripening and growth. e) Plant morphogenesis. f) Response to biotic and abiotic stresses such as high/low temperatures, salinity, pollution In conclusion, arginine plays multi-faceted roles in lots of plants process. It is a key amino acid for the plant correct development and for it to face the biotical and abiotical stresses that the plant may suffer. Histidine Acts as Nickel and Zinc chelating at cell ph, both minerals needed for a correct enzyme function. It plays an essential role for embryo survival, without which high rate embryo abortions occur in plants. Lysine

16 It has been found no specific functions of this amino acid beyond forming part of proteins. Hydroxylic Serine Serine has an important role in the plant function. Its derivate, phosphatidylserine, is part of the structure of the cell membrane and its lack leads to deformity of this layer, which leads to some serious problems like: a) Lower on the tolerance of the plants to stress. b) Increase of the embryo abortion rate on some species. c) Total male gametophyte lethality in some species. d) Altered mineral balance. e) Decrease of the folate production, which is key for the formation of embryos and post-embryonic root development. f) Inefficiency on the control of the photorespiration, leading to energy availability problems for the plant. A good supply of this amino acids will help the plant not to have these conditions.

17 Threonine It has been linked the role of this amino acid to plant defense mechanism and the signaling of different metabolic pathways but very little is known about the function of this amino acid, despite the fact that it is present in the structure of many different proteins. Sulfur-containing Cysteine This amino acid is the precursor and pathway activator of many of other key compounds, such as vitamins, antioxidants and many defense compounds, so a good supply of this amino acid will lead the plant to improve the resistance to stress, diseases and infections. One special product that is synthetized from this amino acid (together with glycine and glutamic acid) is the glutathione. This compound is a powerful antioxidant which helps the organism to deal with free radicals formed in the metabolism, helping retarding senescence and plant damage.

18 Methionine It transports sulfured groups through the plant in the form of S- adenosylmethionine, the major donor for transmethylation reactions. This reactions are present, for example, during the production of some vitamins like B12 or the production of phosphatidilcoline, an essential cell membrane compound. This amino acid is also the precursor for the biosynthesis of ethylene, compound that allows the fruit ripening. So the role of this amino acid is key for the plant growth since it is needed for the production of ethylene, but it is also important for the general metabolism of the plant since transmethylation is a very common and important reaction in the plant. Amidic Asparagine Asparagine plays a central role in Nitrogen transport and storage in plants, and it is implicated in Nitrogen metabolism in different phases:

19 a) Nitrogen mobilization in germinating seeds. Asparagine is the main distributor of Nitrogen all over the plant. Germinating seeds need Nitrogen supplies before they can be autonomous in the production of nitrogenous compounds, so Arginine carries the nitrogenous compounds from the plant leaves to the seeds. b) Nitrogen recycling and flow in vegetative cells in response to biotic and abiotic stresses. Asparagine responds to stresses like darkness, salinity or damage where the plant starts to starve. Recycling of Nitrogen is key for the plant having enough nitrogenous substances not to starve at the first stages of these stresses. c) Nitrogen remobilization from source to sink organs. Nitrogen is absorbed mainly by the roots and it has to be transported all over the plant. The source organs in this case are the roots, and the sink organs are the part of the plant that needs this Nitrogen. But this transport also occurs when some organs, like the leaves, start the senescence process. Senescence is the wilt of any organ. In deciduous trees for example this process is massive, and the leaves that fall are full of nutrients and elements like Nitrogen. This Nitrogen has to be recycled to other parts of the plant to avoid losing it in form of Asparagine. Glutamine

20 This amino acid shares the Nitrogen recycling function with Asparagine. It recycles the Nitrogen that respiration produces and also a small portion of the exportations of the senescent organs are transported by this amino acid. 3. Conclusions The general effects of the amino acids in the plant could be summarized into six: a) Forming the structural proteins and the enzymes that will allow the plant to grow and to develop its metabolic processes. b) Acting directly as amino acids, or as part of proteins, in the anti-stress mechanisms that will protect the plant from infections or another kinds of stress. c) Helping the plant to absorb, transport and recycle the nutrients. d) Being the substrates from which many compounds, like hormones or other amino acids, are synthetized. e) Regulating the osmotic pressure of the cells and tissues. f) Chelating some Micronutrients like Zinc, Copper or Iron.

21 4. ARTAL Solutions Aminotal Super AMINOTAL SUPER is a bioactivator with a high concentration of free amino acids obtained by acid hydrolysis. Due to its elevated content of amino acids the application of this product: Will activate the crop metabolism. Will provide enough Nitrogen to its development. Will improve the microelements assimilation (thanks to the complexing effect of the amino acids). Will enhance the pesticides effect. AMINOTAL SUPER application is recommended during the active growth stages of the crop and during the freezing periods since it invigorates the crop and improves its development under stress conditions. The aminogram of the product is the following: ASP-VAL-GLU(9%)-PHE-SER-ILE-GLY-LEU-THR-LYS-ARG-HIS-ALA- PRO-TYR-HYP-MET AMINOTAL SUPER presents a fully assimilable formula, so it can be applied through foliar or radicular way. AMINOTAL SUPER is recommended for all kinds of crops: Fruit (pip and pit), citrus, horticulturals, cereals and ornamentals. ELEMENT GUARANTEED COMPOUNDS Free Amino acids 30,00% w/w = 37,0% w/v Total Nitrogen 9,00% w/w = 11,16% w/v Soluble Liquid ---

22 Vegeamino VEGEAMINO is a bioactivator with a high concentration of vegetal origin obtained by hydrolysis. The application of this product in the crop: Will activate the crop metabolism. Will provide enough Nitrogen to its development. Will improve the microelements assimilation (thanks to the complexing effect of the amino acids). Will enhance the pesticides effect. AMINOTAL SUPER application is recommended during the active growth stages of the crop and during the freezing periods since it invigorates the crop and improves its development under stress conditions. The aminogram of the product is the following: ASP-VAL-GLU(14%)-PHE-SER-ILE-GLY(5%)-LEU-THR-LYS-ARG-HIS- ALA-PRO-TYR-HYP-MET AMINOTAL SUPER presents a fully assimilable formula, so it can be applied through foliar or radicular way. AMINOTAL SUPER is recommended for all kinds of crops: Fruit (pip and pit), citrus, horticulturals, cereals and ornamentals. ELEMENT GUARANTEED COMPOUNDS Free Amino acids 20,00% w/w = 24,00% w/v Total Nitrogen 3,90% w/w = 4,83% w/v Soluble Liquid ---