Jasmonic Acid: Plant Hormone Biosynthesis, Signaling, and Defense Roles

[00:00:03][Music] hello everyone welcome you all to the EPG Panchala botany myself dr. Shyam Mitra working as an assistant professor in the Department of botany savitribai phule a Pune University Pune today I will talk on jazz Manik acid jazz malic acid is a plant hormone chemically it's a derivative of cyclopentanone and it is involved in various cellular processes in plant interestingly it is also playing an important role in plants biotic and abiotic defense responses in this module we will study how jazz malic acid is synthesized conjugated transported and inactivated we will also see the physiological effects that this hormone has on plants and the molecular mechanism involved in jazz monic acid signaling first we will see how Jasmine ik acid is synthesized in plants it is synthesized by the octa dekinai pathway its biosynthesis starts in the chloroplast first activation of lipase releases fatty acids from the membrane lipids and free linolenic acid is served as the precursor for Jasmine ik acid biosynthesis linolenic acid is further oxygenated by a specific lipoxygenase to form 13 hydro peroxide och today katrien O ik acid this is abbreviated as 13 HP ot the 13 HP OT is subsequently cyclized 2 in 12 ox o fight or die in oeq acid that is opda by the enzymes L in oxide synthase and allene oxide cyclists respectively after this Oh PDA is transported from chloroplast to the paroxysm and its movement is facilitated by the ABC transporters in the paroxysm the olefinic bond of the cyclopentanone ring is reduced by the enzyme opda reductase and NADPH is used as a cofactor after being reduced it undergoes three cycles of beta oxidation by the assign Co a oxidase one enzymes multifunctional protein and n3 keto Asil Co a tireless and converted to - manic acid now we will see after being exported from the paroxysm to cytosol how the just malic acid is further metabolized it is either conjugated with amino acids glucose or esterified - its methylated form methyl just Minette in the cytosol among all these GA conjugates jei solution is the most active form and plays a significant role in orchestrating plant defense responses after injury and insect herbivore the esterified form of jasmine ik acid that is methyl just Manette was first detected in the essential oil from the petals of just minam grandiflorum this esterification process is catalyzed by the enzyme jasmine 8 o methyl transferase methyl Jasmine it is extremely volatile in nature and easily diffusible through the membrane therefore it is considered as an important cue for both intra as well as interplant signaling catabolism of Jasmine Ed's includes the conversion of jasmine ik as and jazz Monica said isoleucine to their respective 12 hydroxy derivatives that is 12 Oh AJ and 1208 jei solution respectively cytochrome p450 are well-known for hydroxylation of small molecules and inactivation of fighter hormones to seep members sip 94 b3 and sip 94 c1 are involved in two successive oxidation process of jei solution now the question is are je and its various forms mobile after wounding or herbivory jasmine ik acid level is increased within two to five minutes throughout the plant therefore jasmine eights are known as long-distance mobile signal would induce je is transported to the root and is responsible for the systemic increase of je level in the root methyl Jasmine it is also mobile and it moves through both xylem and phloem if methyl respond it is applied exogenously it first diffused in the leaf tissue and entered the phloem stream along with four to assimilates however due to exchange of constituents between xylem and phloem methyl Jasmine it also enters the xylem stream mainly to the source via photo assimilates now we will see the physiological effects of Jasmine aids on plant Jasmine its modulate the expression of a variety of genes and play major role in plant photosynthesis growth senescence germination reproductive development and defense response to biotic and abiotic stress Jasmine let's decrease the expression of genes that regulate photosynthesis rubp case and other vehicles activists are the two major photosynthetic in Symes downregulated after Jasmine a treatment hence photosynthesis gibberellic acid are the growth promoting hormones that play important role in stem elongation leaf expansion etc to promote growth bioactive GA binds to the cognate receptor and leads to pretty awesome dependent degradation of it repressor protein della however j inhibits the degradation of della and restricts growth in addition to photosynthesis and growth jasmine it's also regulate various genes involved in leaf senescence exogenous application of Jasmine its causes chlorosis that may lead to senescence moreover it is known that jasmine Nets interact with many kindnesses and transcription factors involved in regulation of leaf senescence jasmine ik acid repression of the photosynthetic protein RCA or Rubisco activase is responsible for leaf senescence in arabic topsis jasmine 'it's also play an important role in germination and sibling development however it was later known that the intermediate of jasmine and biosynthetic pathway opda is the compound inhibiting the seed germination jasmine 'it's are important for the proper development of reproductive organs and show different phenotypes for example jasmine --it in sensitive mutant of rub-a-dub sister Lyanna showing a male sterile phenotype on the contrary the j insensitive tomato mutant j1 is female sterile and does not develop seeds the main intermediate of the j by synthesis 6:12 ox o fight or die Ayane Cassie seems to be the essential for proper seed development Jasmine eek acid also inhibits flower bud for me jasper nets are accumulated after wounding and hard before jasmine nets are known to be the signal for induction of stress responses jasmine 'it's induce the accumulation of major anti herbivore defense metabolites and entry nutritive proteins for example Jasmine had induced in the Lacaze know--let's in Brassica species in nicotiana after herbivory Jasmine adds are transported to the root and initiate the biosynthesis of nicotine another defense metabolites 17 hydroxy Geralyn Lila you'll die terpenoid glycosides is also increased after help every in a jasmine ik acid dependent manner Jasmine it's also induce the production of volatile organic compounds required for indirect defense not only defense signaling our trade-off between plant growth and defense metabolite accumulation is also seen to be brought by harvey very induce Jasmine at accumulation Jasmine and induced defenses impose significant costs on a plant growth Jasmine it's inhibits photosynthesis and plant growth the resources are used for synthesis of different metabolites which provide resistant to the forgivers now we will see the mechanism by which Jasmine adds regulate gene expression from the previous lives we know that the most bio active form of Jasmine 'its is jei solution it is structurally and functionally similar to the fighter toxin coronet in coronating in sensitive protein belongs to a highly comes out F box protein that recruits the substrate to skp one called one F box protein III ubiquitin ligase complex another protein called as Jasmine at zeem domain or jazz protein is a transcriptional repressor and binds to Mik transcription factor the complex of COI one and Jaz is the receptor for J signaling bioactive je isoleucine binds to both the ligand binding pocket on COI one and as well as the peptide of a by patent jazz one day Ron Jasmine de gran has a conserved helix for koi one anchoring and a loop to trap jei solution in the pocket a third essential component of this complex is inositol pintuck is phosphate that interacts with both koi one and jazz adjacent to the ligand and potentiates this complex there is another co-repressor called as topless and the adaptor protein called as normal interactor of jazz or Linda attached to this complex the binding of jei solution to the SEF koi jazz complex leads to the degradation of jazz protein by 26s proteasome pathway degradation of jazz releases the mcdu transcription factor from repression and induces the expression of genes that are required for stress response it has also been shown that the je biosynthesis intermediate opda also regulates expression of je response genes in a koi dependent and independent manner to summarize today's topic jasmine ik acid we have seen that jasmine ik acid is an oxy lipping which is partly by synthesized in the chloroplast where OPD is formed partly in the paroxysm where jasmine ik acid is formed and finally jasmine ik acid is released to the cytosol after it is released to the cytosol it is further metabolized to different dairy among them - Monica said isoleucine is the major bioactive conjugates which plays an important role in defense signaling previously it was thought that only jasmine ik acid is the bioactive compound but later on it is known that it's precursor and intermediates are also playing a significant role in defense signaling koi one is the receptor for jei solution and jei solution and Chi complex binds to the Jazz protein which is the repressor protein for defense response genes finally with 26 s proteasome this complex gets degraded and the defense responsive genes get activated thank you you