Elicitor-Induced Modulation of Indole Alkaloid Biosynthesis in Catharanthus Roseus

[Music] [Music] welcome to nptl online certification

course on pharmacognosy and metabolic engineering uh now we'll go to lecture 24 where the role of elicer in

modulating alkaloid accumulation particularly indor alkaloid accumulation will be covered so let us go to the

concepts covered so before I go to the elicit treatment for applic of indol alkaloids particularly on the mechanism

aspects I will go uh for a quick revision whatever I have covered in the ear ler

class okay so let's go to the board now what we have covered in the last class was uh the early steps of indol alkaloid

biosynthesis so there what we have seen that cryptomine

and seanin so seanin is basically coming from the tarpo pathway so from geranial

through multiple steps and this stript tamine and cyanin they joins together and form

the stripto sidin and this strictosidine

subsequently strict to stct C right subsequently form strictosidine

aglycon by the action of uh uh uh glucosides so and the enzymes responsible are I

have already mention this one is TDC and actually these two joins together so I must show it in that way

otherwise again you will be confused so sorry

sorry and actually tryptamine originates from tryptophan and now we put the enzyme so

this was stopan DEC carboxilate this one stto in synthes and this one uh this stto in glucosides which makes stto in

aglycon and stto in aglycon is a very active compound and that leads to formation of more than

300 uh different indor alkaloids in different plants now and so [Music]

but uh from stripto in aglycon there are three different skeletal structures originate uh and that leads to different

group of alkaloids so one major alkaloid what I have mentioned in the previous class that was AAL

sin another one is

CA ranin and another one is

vindoline now the structures uh these three alkaloids the chemical structure the structure is

different the skeletal structure so this was uh this this comes under cinan thin type Cor

cordan thean type in one of the later classes I will show you the structure in the form of

slides this one is called eogan type and this one is

called Plum run type

what I have also shown that from this stto in a

glycon it forms 421

dehydro gasio sizin a big name and from dehydr gasio sizing

different Roots originate one root goes towards catharanthine and vindoline this we will

study in detail and the other roote which goes

towards camine and camine can be converted

into aalin or

imum camine and this subsequently

formed Tetra Hydro Al stonin so this name I have not mentioned

yesterday so this is Tetra Hydro

Alin okay and aalin can be converted

into serpentin now Tetra Hydro

alstonine actually one can find in the plant called alonia asonia species different species

are there so there this alkaloid accumulates so this is in brief uh I have uh uh made the division

for you and this is Tetra Hydro alstonine synthes One enzyme is working here and this conversion is

by peroxides right so this is a brief revision so

this is more or less I have covered so now we go to the next aspect that is the mechanism of elicit

induced upliftment of this alkaloid okay so if you remember that I have

drawn this diagram in the previous class where it is showing basically a model for elicit signal transduction leading

to strict toyin synthes gene expression so what we see here that in the membrane there is a deceptor and a elicit

molecule comes and bind and that leads to influx of calcium channels which can directly with the

without the uh without the involvement of jasmonate can activate a transcription

Factor like cr r BF okay and that basically binds in the elicited response

Elements which is also called ba and the other one is that uh that uh elicit when it attached to that

that in turn also activates the uh octano pathway leading to the synthesis of jasmonates

and that jasmonate will be perceived by the jasmonate receptor and then through a protein kyus activity

ultimately uh this uh activates one transcription Factor like

Orca which comes and joins so now this aspect we will see in detail in the next slide then in the board so this is about

the mechanism of activation

of indle alkaloid

pathway in see codon Rosas

upon East extract treatment so let us

draw the diagram first so this is what is the plasma

membrane where there must be a receptor receptor is is Bally a

protein uh so this is what we can say receptor and

the this is the elicit that is East extract it

basically comes and bind here okay and so as a result of that what is going to happen let us see very in a very

brief way this is what is there inside the

nucleus [Music] so this is

nucleus this is cytoplasm and this is the plasma membrane so what happens that

uh receptor upon binding with the East extract it activates the jasmonic acid so that means leading to the activation

of jasmonate so one Arrow we can put it here and write it j a j stands for jasmonic acid and

increased level of G I put it in Arrow upper side that means it increased accumulation of jasmonic acid level okay

and that once it increase let us see what what is going to happen but before that I need to

draw here in the inside the nucleus okay so one is for this

this was a part of the promoter so this is an element Upstream element and then you have

the coding region for d and so on okay

so we will have to also draw the Str Str well uh

P so this is the promoter region here lies the tataa box for S

and this is nucleus next what we see this jasmonic acid uh what it does it activates the

orca3 so activation of orc3 which comes and bind near the data box so this

is I'll put Orca not three I am not mentioning here o RCA octoid responsive catharanthus apal

elements so it is a positive regulator of this uh DDC biosynthesis and not only that this e

extract also activates another transcription factor which comes and bind here which is

called BPF 1 now these are the positive Regulators

which will uh allow the Str Str Gene to express and uh TDC Gene to express okay and

orca3 also activates the St Str as well but there are some transcription factors which are

basically uh are the negative regulators for example like J City and like I put it in a different color like J

City and GBF so this try to block the activ

now J C is basically a Jin finger catharanthus transcription factor and BPF one is basically box P binding

Factor it is actually belongs to this B zip class and GBF is basically the Gbox

binding Factor so uh so what happens in normal cases this J C and GBF it binds so uh

uh and it binds in the promoter region and that is why it is not allowing the Str Str or TDC Gene to be transcribed so

upon the E elicitation happens so that activates the jasmonic acid and through jasmonic acid orc3 is getting

activated uh otherwise without this also uh okay it

also activates directly uh the BPF one so these are the positive regulators and once these are activated so that

actually uh remove the negative regulator and it binds and as a result of that what we see the transcription of

these genes that means transcription of uh the Str Str as well as TDC this is in brief a mechanism of

activation of indid pathway in cathan Rosia culture uh upon e extract treatment

Catania culture so it could be hary root culture it could be shoot culture it could be

cell culture so next we will see another model in the next slide

this model I briefly mentioned in one of the earlier classes when I have spoken about this elicitation in general but we

will again discuss this because this is directly in this relevant to this context so this is a

model for model for jasmonic acid J stands for jasmonic

acid induced s gene expression s means stricty

synthes mediated gen expression uh mediated by what we can say

mediated by the mediated by okay I'll put the the not

here mediated by the word

c three transcription

factor in catharanthus roseus

culture so just moonet jasm Monet okay I put the jasm

Monet towards little bit left otherwise I need The Bard B more so go to

pin and take this color

jmet jasmonate activates jasmonic acid receptor and that by some unknown

mechanism activates a

General uh transcription factor which was not fully known yet so so that is I put it in TF TF is

basically transcription activating Factor TF I'll put a TF here TF stands for transcription

activating Factor so that is getting activated so t a f when it is activated how I will denote I will denote by

adding a start so this in this means that it is

now activated and then

which in turn will activate the specific transcription

Factor required for activating the pathway that specific transcription factor is basically the

or CA and3 is one specific one this or C3 so was C3 will get

activated sorry size is not good

so activation means I put this star star means activated

and this activation what is going to happen so there are two things one let us

draw the DNA so here lies the jonet response element

J stands for jasmonate response element TF stands for transcription activating

Factor just smallet

response element so here this TF activated trf will come and bind

so I have to put some Arrow to add it here so right

this and that basically what will happen it will activate the uh the genes for orca3 so that leads to activation of

WC3 so what we put mRNA so this a is

basically showing activation of or

C3 so maybe or C3 I put it in this color so

uh so this is activates and then what will happen that it it it leads to activation of

orca3 and so that means and then War C3 is getting activated so this war C3 will come and

bind here so where is the word C3 here is the word C3 it will come and bind o r c

A3 so the activated WC3 will come and bind so it is activated and where it binds it binds in

the DNA where is where lies the jasmonate and elic response element so J stands for J E stands

for jmet elicer

response element okay and once it is there then what it does it basically activates

the Estrin so this is mRNA so what I will write here this

leads to activation of St are

gen so activation of estr gen and that leads to

the uh formation of the St protein and which plays important role in binding tryptamine and cyanin leading to the

formation of strictosidine so this part is basically the uh orc 3 activation o r c

A3 activation and this is all is basically this

transcriptional Cascade transcriptional so this is in brief a

model or jmet induced s Str gene expression so what Str Str does is basically Str Str

converts uh tryptamine

and C tripin tripin

SEO loanin to stripto sidin and pathway moves so the St Str

plays very important role so here is the S okay so this is all about the model

for jonet induced St Str gene expression now uh with this I will end this class I will not go into

the specific examples of uh here root culture expressing the transcription factor maybe in one of the subsequent

classes I will bring that issue so with this I will end this class thank you