This document discusses antisense RNA technology and its role in crop improvement. It begins by introducing antisense RNA as a method for inhibiting gene expression through complementary base pairing. It then discusses various applications of antisense RNA technology in crop improvement, including delaying fruit ripening in tomato and flower senescence in carnation, producing male sterility in petunia, and reducing neurotoxins in crops like khesari. The document concludes by noting that antisense RNA technology is an efficient gene knockdown method that could be useful for genetic improvement in many plant species.
RNAi is a powerful, conserved biological process through which the small, double-stranded RNAs specifically silence the expression of homologous genes, largely through degradation of their cognate mRNA.
RNAi is a powerful, conserved biological process through which the small, double-stranded RNAs specifically silence the expression of homologous genes, largely through degradation of their cognate mRNA.
MBB 501 PLANT BIOTECHNOLOGY
INFORMATION ABOUT DIFFERENT DNA MODIFYING ENZYMES
WHAT IS AN ENZYME?
Alkaline Phosphatase
Polynucleotide kinase
Terminal deoxyneucleotidyl transferase
Nucleases
Exonuclease
Bal31 Exonuclease III
Endonuclease
S1 endonulease
Deoxyribonuclease 1 (Dnase 1)
RNase A
RNase H
Restriction Endonuclease
PvuI
PvuII
Different types of endonuclease enzymes
The recognition sequences for some of the most frequently used restriction endonucleases.
Categorization of enzymes
Isoschizomers
Neoschizomers
Isocaudomers
Introduction
Ti plasmid
Agrobacterium tumefaciens
Ti plasmid structure
Overview of infection process
Ti plasmid derived vector systems
Cointegrate vectors
Binary vectors
Agrobacterium mediated transformation of explants
Conclusions
References
introduction
What is virus
What is virus resistance plant
History
Gene use for develop virus resistance plant
Coat protein gene
cDNA of satellite RNA
Defective viral genome
Antisense RNA approach and
Ribozyme – mediated protection
conclusion
References
RNA interference (RNAi): Cellular process by which an mRNA is targeted for degradation by a dsRNA with a strand complementary to a fragment of such mRNA.
Arabinose Operon is a self-regulatory sequence of genes used by material to metabolize a five-carbon sugar called arabinose when there is a deficiency of glucose in the environment.
MBB 501 PLANT BIOTECHNOLOGY
INFORMATION ABOUT DIFFERENT DNA MODIFYING ENZYMES
WHAT IS AN ENZYME?
Alkaline Phosphatase
Polynucleotide kinase
Terminal deoxyneucleotidyl transferase
Nucleases
Exonuclease
Bal31 Exonuclease III
Endonuclease
S1 endonulease
Deoxyribonuclease 1 (Dnase 1)
RNase A
RNase H
Restriction Endonuclease
PvuI
PvuII
Different types of endonuclease enzymes
The recognition sequences for some of the most frequently used restriction endonucleases.
Categorization of enzymes
Isoschizomers
Neoschizomers
Isocaudomers
Introduction
Ti plasmid
Agrobacterium tumefaciens
Ti plasmid structure
Overview of infection process
Ti plasmid derived vector systems
Cointegrate vectors
Binary vectors
Agrobacterium mediated transformation of explants
Conclusions
References
introduction
What is virus
What is virus resistance plant
History
Gene use for develop virus resistance plant
Coat protein gene
cDNA of satellite RNA
Defective viral genome
Antisense RNA approach and
Ribozyme – mediated protection
conclusion
References
RNA interference (RNAi): Cellular process by which an mRNA is targeted for degradation by a dsRNA with a strand complementary to a fragment of such mRNA.
Arabinose Operon is a self-regulatory sequence of genes used by material to metabolize a five-carbon sugar called arabinose when there is a deficiency of glucose in the environment.
RNAi (RNA interference/ Gene Silencing) and its importanceKaurKawaljeet
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is a conserved biological response to double-stranded RNA that mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes. Small pieces of RNA can shut down protein translation by binding to the messenger RNAs that code for those proteins. RNA interference is already proving to be an invaluable research tool, allowing much more rapid characterization of the function of known genes. More importantly, the technology considerably bolsters functional genomics to aid in the identification of novel genes involved in disease processes.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
Gene silencing techniques for crop improvementJhilickBanerjee
Gene silencing is a technique that aims to reduce or eliminate the production of a protein from its corresponding gene. Gene silencing is the regulation of gene expression in a cell.
Gene silencing can occur during either transcription or translation.
Gene silencing is often considered as “Gene knockdown’ i.e their expression is reduced. In contrast , when genes are knocked out they are completely erased from the organism’s genome and thus have no expression.
Methods used to silence genes include RNAi, CRISPR or siRNA, these reduce the expression of the gene by 70% but do not completely eliminate it.
RNA interference (RNAi) is a mechanism that inhibits gene expression at the stage of translation or by hindering the transcription of specific genes.
RNAi targets include RNA from viruses and transposons.
Antisense RNA Technology for crop improvement.pptxSanyamPatel2
Improvement of crops by following genetic engineering techniques:
Gene silencing
Post transcription silencing
Post translation silencing
Antisense RNA
RNA interference
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is a conserved biological response to double-stranded RNA that mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes. This natural mechanism for sequence-specific gene silencing promises to revolutionize experimental biology and may have important practical applications in functional genomics, therapeutic intervention, agriculture and other areas.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
3. Introduction
Antisense RNA technology is a method that used for the inhibition of
gene expression.
The antisense nucleic acid sequence can be either synthetic
oligonucleotides of 30 nucleotides (nt) or longer antisense sequence.
This technology may used for therapeutic purpose, functional genomics
and target validation.
Antisense RNA technology can be used to prevent viral disease.
Antisense RNA technology used for improvement of quality characters
in plants.
4. Antisense RNA approach
Antisense RNA is a single stranded RNA that is
complementary to messenger RNA (mRNA) transcribed
within a cell.
There are many cases in both prokaryotes and eukaryotes
where a single stranded RNA base pair with a
complementary region of an mRNA and its prevent
expression of the target mRNA.
Sense strand and antisense strand:
refers to the original sequence of DNA or RNA
molecule while, antisense refers to the complementary
sequence of DNA or RNA molecules.
5. Types of Antisense RNA Approach
Non Catalytic antisense RNA
Non catalytic antisense RNA strands blocks RNA
processing i.e. – modified the RNA strands or
transcription
Catalytic antisense RNA
Catalytic antisense RNA also called ribozymes which will
cleave the mRNA molecules at specific sequence
6. Construction of antisense RNA
• Antisense genes or RNA are constructed
by reversing the orientation of gene with
regard to its promoter.
7. Mechanism of non catalytic antisense gene
• Three types mechanism in antisense gene prevent gene
expression.
• mRNA not available for translation machinery.
• Degradation by dsRNA specific enzyme RnaseH which breaks
phosphodiester bond and degrades target mRNA.
• It repress the splicing process in pre mRNA .
8. Catalytic Antisense RNA or Ribozymes
Ribozymes are RNA enzymes that have endoribonuclease
activity .
Ribozymes used for gene knockdown application have a catalytic
domain that is flanked by sequence complementary to the target
RNA.
Once target RNA destroyed ribozymes dissociate and
subsequently can repeat cleavage on additional substrate.
First isolated from viroid RNAs.
Ribozyme activity enhanced through high Mg++ and high amount
of target RNA.
9. RNA interfernce(RNAi)
• RNAi is a advanced technique of antisense RNA technology.
• RNAi is a natural powerful mechanism that is thought to
have arisen for protection from viruses and transposon.
• RNAi first discovered in nematode C. elegans by Andrew z.
fire and Craig mello and get nobel prize in 2006.
• RNAi stop the gene expression through complementory
small double stranded RNA molecules.
Mostly two types of RNAi molecules studies.
• Small interfernce RNA (siRNA).
• microRNA (miRNA)
11. Key enzymes in gene silencing:
Haruhiko Siomi & Mikiko C. Siomi Nature /vol 457/22 2009
12. DICER A TYPE III RNA-SPECIFIC RIBONUCLEASE
Enzyme involved in the initiation of RNAi. It is able to digest
dsRNA into uniformly sized small RNAs (siRNA)
Dicer family proteins are ATP-dependent nucleases.
Rnase III enzyme acts as a dimer
Dicer homologs exist in many organisms including C.elegans,
Drosphila, yeast and humans
Loss of dicer leads to loss silencing processing in vitro
Four kind of dicer in Arabidopsis thaliana
DCL1-generation of miRNA
DCL2-Produce viral derived siRNA
DCL3-Generate DNA repeat associated siRNA
DCL4-Synthesis of tasiRNa
13. AGO Protein Family
RNA binding proteins, through conserved PAZ domain
Assemble into RISC
Direct cleavage of target mRNA
10 AGO members
Functional diversification of RNA silencing is linked to the
variation between AGO family members
e.g., AGO1-associated with miRNA pathway, AGO4 with
endogenous siRNA silencing
14. The RNA-induced silencing complex
(RISC)
Multicomponent RNAi nuclease (500 kDa):
1. Member of Argonaute family
2. RNA binding proteins
3. RNA helicase
4. Ribosomal protein
Sequence-specific nuclease that uses small RNA as
guides to target specific messages based upon
sequence recognition.
Cleavage site of cognate RNA (mRNA) is placed near the
middle of the region bound by the siRNA strand.
16. The small interference RNA
(siRNA)
• siRNA made artificially or produced in vivo from
double stranded RNA precursors.
• 21-25 nucleotides long .
Each strand of siRNA has:
a. 5’-phosphate termini
b. 3’-hydroxyl termini
c. 2/3-nucleotide 3’ overhangs
17.
18. miRNA
21-24 nt in length
The miRNA are endogenous small RNA guides that repress
the expression of target genes.
Differ from siRNA in biogenesis not in functions, although
mechanisms can be different. mRNA cleave when
complementarities is extensive, repress translation when
not.
More than 100 miRNA in Arabidopsis essential for plant
development.
20. Translation of cell mRNA is suppressed by its
complementary pairing with miRNA.
It is known that miRNAs are produced from cell
untranslated transcripts of 120–150 nt and even
produced by DICER from a miRNA precursor.
This interaction induces degradation of the target
mRNA or directly blocks translation.
Endogenous mRNA Silencing Caused by miRNA
23. tasiRNA
21-22nt long
Generation initiated by miRNA and or require DCL4 & RDR6
Role in plant development and hormone signaling
Down regulate auxin response factors
24. Chromatin assisted siRNA
24-25nt long
Most abundant class of siRNA
Generated by DCL3/RDR2/RNA PolIV/AGO4 to
transcriptional silencing
Role in DNA methylation & transcriptional gene silencing
25. natsiRNA
Endogenous siRNA derived from the overlapping
region of a pair of natural antisense transcripts
(NATs).
20-21nt long.
Regulate salt stress response in Arabidopsis.
Major source of endogenous siRNA for gene
regulation in response to different environmental
conditions.
26. scnRNA
Protozoan
First Identified in Tetrahymena thermophyla
27-30nt long
Role in developmentally programmed DNA
elimination (Lee and collins, 2006)
27. piRNA
Mammalian germlines & stem cells
26-31nt long
piRNA attacks a transcribed transposon & the
cleaved product contribute to the piRNA
production (Aravin et al., 2006)
29. lsiRNA
30-40nt long (long siRNA)
Share common features with endogenous siRNA
Induced either on pathogen infection or specific growth
conditions
Down regulation of gene expression into the form of mRNA
decapping or 5’-3’- degradation
32. Slow Fruit Softening in Tomato
• In Tomato enzyme polygalacturonase (PG) degrades pectin
which is the major component of fruit cell wall.
• It leads to the softening of fruits and deteriorate the fruit
quality.
• In transgenic tomato expression of PG antisense RNA
dramatically inhibit PG mRNA accumulation and enzyme activity
Theologis et al., 1992
33. Delayed Fruit Ripening in Tomato and Flower
Senescence in Carnation
• Fruit ripening and flower senescence is
promoted by ethylene phytohormone.
• Ethylene biosynthesis involves two enzymes
viz- ACC synthase (encoded by acc gene) and
ACC oxidase (aco gene)
• Methionine AdoMet ACC Ethylene
• Gene acc was suppressed by using antisense
of its cDNA.
• That antisense reduced more than 90% of
ethylene production.
Hamilton et al., 1992
34.
35. Male Sterility and White Flower Production in Petunia
• Flavonoids are essential for normal pollen development and
function.
• Chalcone synthase is a key enzyme for flavonoides synthesis.
• In Petunia antisense of enzyme CHS is insert.
• Transformed plants of Petunia have negligible CHS activity and
produce white flower and non functional pollen.
• For maintenance of male sterile line we give flavonol chemical
during pollen development.
Meer et al., 1992
36. Changed Fatty Acid Composition of Brassica Oil
Enzyme stearoyl-ACP desturase catalyze the conversion of
stearoyl ACP to oleoyl-ACP.
Transgenic B. rapa and B. napus plants containing the
antisense RNA of B. compestris stearoyl-ACP desaturase.
Transgenic plants highly reduced level of oleic acid and
increase the level of stearic acid from less than 2% to up to
40%.
These modification are aimed to generating saturated fatty
acid now obtained from cocoa.
knutzon et al, 1992
37. Protection of Plants From Viral Infection
Transgenic Barley resistant to BYDV (Barley yellow
dwarf virus) (Wang et al., 2000).
Transgenic Banana resistant to banana bract mosaic
virus (Williams et al., 2004).
In banana designing RNAi vector aimed at silencing the
coat protein region of the virus that is resistant to
BBrMV.
38. Production of Low Glutenin Rice
The rice mutant line LGC-1 (Low Glutelin Content-1)
was the first commercially useful cultivar produced by
RNAi (Kusaba et al, 2003).
It is a low-protein rice and is useful for kidney patient
unable to digest glutenin protein.
39. Reduced Lignin Content in Jute
A possible application of RNAi involve the down
regulation of a key enzyme in biosynthetic pathway of
lignin.
The enzyme 4-coamarate ligase (4-cl) is a type of key
enzyme in early stage of lignin synthesis
Transgenic jute variety expressing RNAi construct to
down regulate the quantity of 4-cl mRNA.
Williams et al., 2004
40. Reduced Gossypol Content in Cotton
Cotton cantains a toxic gossypol terpenoid. It protects
cotton plants from attack of insects and other pathogens
but it is harmful for both animal and human.
Transgenic cotton plant expressing a RNAi construct of the
d-cadinene synthase gene to fused with the seed specific
promoter caused seed specific reduction of gossypol
metabolites.
kumar et al., 2006
41. Increasing Grain Amylose Content in Wheat
Food rich in inefficiently digested carbohydrates such as
fiber are considered to be health promoting.
The major source of plant derived carbohydrate is
starch which, is composed of amylopectin and amylose
polysaccharides.
For increasing the amylose content in wheat grains a
RNAi construct design to silence the gene encoding
starch branching isozymes of amylopectin synthesis.
This result increase amylose content in wheat grain by
70% of total starch.
Tang et al., 2006
42. Reduced Neurotoxin in Khesari
Khesari (lathyrus sativus) is a legume crop .
Khesari contain a neurotoxin BOAA which causes
paralysis in lower limbs called lathyrism.
RNAi technology can be used to silence the gene
responsible for BOAA.
BOAA genes may be linked to this unique crop with
drought and flood tolerance.
So, bringing down the levels of BOAA to safe
concentration rather then totally silenced the gene.
Williams et al., 2004
43. Reduced Caffeine Content in Coffee
Caffeine is a stimulant of the central nervous system.
Its adverse effect include insomania and restlessness.
10% of coffee on the world shared by decaffeinate
coffee. which have 2mg to 4mg caffeine per cup while
standard cup of filter coffee generally contains 60 to 150
mg caffeine.
RNAi technology has enabled the creation of varieties of
coffee that produced low caffeine content.
Van Uyen, 2006
44. Production of Blue Rose
Flower colour in plants by Anthocyanin
Violet to blue colour is due to Delphinidin and red
colour due to cyanidin anthocyanin
RNAi technique used for cyanidin gene knockdown
A new delphinidin gene introduced into rose which
converted red colour into blue colour.
46. Improve Fruit Quality by RNAi
Broothaerts et al., (2004) reported the production of
transgenic apple trees. They are able to self pollinate
and develop fruits.
This break through was achieved by silencing the S-
gene responsible for self incompatibility.
Transgenic apple fruits silence the key enzyme
autocatalytic ethylene production was displayed an
increased shelf life (Dandekar et al., 2004).
Guo et al., (2005) studied that the transgenic citrus
down regulate the putative pectin methylesterase gene.
47.
48. Advantages
Highly gene specific
High gene silencing efficiency
Screening targeted plants takes less time
Highly inducible
Disadvantages
It does not knockdown a gene for 100%
siRNA tends to activate unwanted pathways
--Expensive
--Ethical problems
49. Conclusion
Based on present discussion antisense RNA technology is a
efficient knock down technology in plants.
It is thought to be useful for genetic improvement even in
plants with low transformation efficiency.
Basic concept of the application of transgene based RNAi to
the genetic improvement of crop plant has been established.
Further studies are needed for its wider application