Simplified way of applicability of introgression breeding for submergence tolerance in rice with special emphasis on physiology of submergence tolerance
Presentation by Rona Azucena on behalf of Dr. Abdelbagi M. Ismail (International Rice Research Institute) at the Global Forum for Innovations in Agriculture (GFIA), February 4, 2014
The presentation provides a brief discussion about mechanism of submergence tolerance in rice crop. The success story of introgression of sub 1 in rice crop.
Rice is a staple cereal of India cultivated in about 43.5 Mha area
Affected by abiotic stresses like submergence
Flash flood - plants are completely submerged for up to 2 weeks
30% (12–14 Mha) of the rice growing area affected
Severe loss in rice productive with an average of only 0.5–0.8 t/ha
Marker Assisted Gene Pyramiding for Disease Resistance in RiceIndrapratap1
Why marker assisted gene pyramiding?
For traits that are simply inherited, but that are difficult or expensive to measure phenotypically, and/or that do not have a consistent phenotypic expression under specific selection conditions, marker-based selection is more effective than phenotypic selection.
Traits which are traditionally regarded as quantitative and not targeted by gene pyramiding program can be improved using gene pyramiding if major genes affecting the traits are identified.
Genes with very similar phenotypic effects, which are impossible or difficult to combine in single genotype using phenotypic selection, can be pyramided through marker assisted selection.
Markers provides a more effective option to control linkage drag and make the use of genes contained in unadapted resources easier.
Pyramiding is possible through conventional breeding but is extremely difficult or impossible at early generations..
DNA markers may facilitate selection because DNA marker assays are non destructive and markers for multiple specific genes/QTLs can be tested using a single DNA sample without phenotyping.
CONCLUSION:
• Molecular marker offer great scope for improving the efficiency of conventional plant breeding.
• Gene pyramiding may not be the most suitable strategy when many QTL with small effects control the trait and other methods such as marker-assisted recurrent selection should be considered.
• With MAS based gene pyramiding, it is now possible for breeder to conduct many rounds of selections in a year.
• Gene pyramiding with marker technology can integrate into existing plant breeding program all over the world to allow researchers to access, transfer and combine genes at a rate and with precision not previously possible.
• This will help breeders get around problems related to larger breeding populations, replications in diverse environments, and speed up the development of advance lines.
For further queries please contact at isag2010@gmail.com
Within the last twenty years, molecular biology has revolutionized conventional breeding techniques in all areas. Biochemical and Molecular techniques have shortened the duration of breeding programs from years to months, weeks, or eliminated the need for them all together. The use of molecular markers in conventional breeding techniques has also improved the accuracy of crosses and allowed breeders to produce strains with combined traits that were impossible before the advent of DNA technology
Association mapping, also known as "linkage disequilibrium mapping", is a method of mapping quantitative trait loci (QTLs) that takes advantage of linkage disequilibrium to link phenotypes to genotypes.Varioius strategey involved in association mapping is discussed in this presentation
Presentation by Rona Azucena on behalf of Dr. Abdelbagi M. Ismail (International Rice Research Institute) at the Global Forum for Innovations in Agriculture (GFIA), February 4, 2014
The presentation provides a brief discussion about mechanism of submergence tolerance in rice crop. The success story of introgression of sub 1 in rice crop.
Rice is a staple cereal of India cultivated in about 43.5 Mha area
Affected by abiotic stresses like submergence
Flash flood - plants are completely submerged for up to 2 weeks
30% (12–14 Mha) of the rice growing area affected
Severe loss in rice productive with an average of only 0.5–0.8 t/ha
Marker Assisted Gene Pyramiding for Disease Resistance in RiceIndrapratap1
Why marker assisted gene pyramiding?
For traits that are simply inherited, but that are difficult or expensive to measure phenotypically, and/or that do not have a consistent phenotypic expression under specific selection conditions, marker-based selection is more effective than phenotypic selection.
Traits which are traditionally regarded as quantitative and not targeted by gene pyramiding program can be improved using gene pyramiding if major genes affecting the traits are identified.
Genes with very similar phenotypic effects, which are impossible or difficult to combine in single genotype using phenotypic selection, can be pyramided through marker assisted selection.
Markers provides a more effective option to control linkage drag and make the use of genes contained in unadapted resources easier.
Pyramiding is possible through conventional breeding but is extremely difficult or impossible at early generations..
DNA markers may facilitate selection because DNA marker assays are non destructive and markers for multiple specific genes/QTLs can be tested using a single DNA sample without phenotyping.
CONCLUSION:
• Molecular marker offer great scope for improving the efficiency of conventional plant breeding.
• Gene pyramiding may not be the most suitable strategy when many QTL with small effects control the trait and other methods such as marker-assisted recurrent selection should be considered.
• With MAS based gene pyramiding, it is now possible for breeder to conduct many rounds of selections in a year.
• Gene pyramiding with marker technology can integrate into existing plant breeding program all over the world to allow researchers to access, transfer and combine genes at a rate and with precision not previously possible.
• This will help breeders get around problems related to larger breeding populations, replications in diverse environments, and speed up the development of advance lines.
For further queries please contact at isag2010@gmail.com
Within the last twenty years, molecular biology has revolutionized conventional breeding techniques in all areas. Biochemical and Molecular techniques have shortened the duration of breeding programs from years to months, weeks, or eliminated the need for them all together. The use of molecular markers in conventional breeding techniques has also improved the accuracy of crosses and allowed breeders to produce strains with combined traits that were impossible before the advent of DNA technology
Association mapping, also known as "linkage disequilibrium mapping", is a method of mapping quantitative trait loci (QTLs) that takes advantage of linkage disequilibrium to link phenotypes to genotypes.Varioius strategey involved in association mapping is discussed in this presentation
Yellow rust seminar by Priyanka (Phd Scholar Genetics and Plant Breeding CSK ...Priyanka Guleria
This seminar explains about the yellow rust disease of wheat: Its genetics and prevention methods as well as molecular techniques to combat yellow rust
Quantitative trait loci (QTL) analysis and its applications in plant breedingPGS
Abstract
Many agriculturally important traits such as grain yield, protein content and relative disease resistance are controlled by many genes and are known as quantitative traits (also polygenic or complex traits). A quantitative trait depends on the cumulative actions of many genes and the environment. The genomic regions that contain genes associated with a quantitative trait are known as quantitative trait loci (QTLs). Thus, a QTL could be defined as a genomic region responsible for a part of the observed phenotypic variation for a quantitative trait. A QTL can be a single gene or a cluster of linked genes that affect the trait. The effects of individual QTLs may differ from each other and change from environment to environment. The genetics of a quantitative trait can often be deduced from the statistical analysis of several segregating populations. Recently, by using molecular markers, it is feasible to analyze quantitative traits and identify individual QTLs or genes controlling the traits of interest in breeding programs.
Marker assisted breeding of biotic stress resistance in Rice Senthil Natesan
A marker is a DNA sequence which serves as a signpost/flag post
linked to the trait/gene of interest and is co-inherited along with
the trait
Presence of specific allele of marker = Presence of specific allele of target gene based on the concept the MAS practiced -R.M. Sundaram
Directorate Rice of Research, Hydrabad , July 3rd 2009, CPMB&B, TNAU presentation
Marker assisted selection( mas) and its application in plant breedingHemantkumar Sonawane
Marker Types,Prerequisites for efficient marker-assisted breeding programmes,Advantages of MAS,Limitations of MAS ,Marker Assisted Breeding Schemes,• 1. Marker- assisted backcrossing,2. Marker- Assisted evaluation of breeding material,3 Gene pyramiding,4. Early generation selection ,Combined approaches,MAB: I level of Selection – FOREGROUND SELECTION,Second level of selection: Recombinant Selection,MAB: III Level of Selection BACKGROUND SELECTION,
Yellow rust seminar by Priyanka (Phd Scholar Genetics and Plant Breeding CSK ...Priyanka Guleria
This seminar explains about the yellow rust disease of wheat: Its genetics and prevention methods as well as molecular techniques to combat yellow rust
Quantitative trait loci (QTL) analysis and its applications in plant breedingPGS
Abstract
Many agriculturally important traits such as grain yield, protein content and relative disease resistance are controlled by many genes and are known as quantitative traits (also polygenic or complex traits). A quantitative trait depends on the cumulative actions of many genes and the environment. The genomic regions that contain genes associated with a quantitative trait are known as quantitative trait loci (QTLs). Thus, a QTL could be defined as a genomic region responsible for a part of the observed phenotypic variation for a quantitative trait. A QTL can be a single gene or a cluster of linked genes that affect the trait. The effects of individual QTLs may differ from each other and change from environment to environment. The genetics of a quantitative trait can often be deduced from the statistical analysis of several segregating populations. Recently, by using molecular markers, it is feasible to analyze quantitative traits and identify individual QTLs or genes controlling the traits of interest in breeding programs.
Marker assisted breeding of biotic stress resistance in Rice Senthil Natesan
A marker is a DNA sequence which serves as a signpost/flag post
linked to the trait/gene of interest and is co-inherited along with
the trait
Presence of specific allele of marker = Presence of specific allele of target gene based on the concept the MAS practiced -R.M. Sundaram
Directorate Rice of Research, Hydrabad , July 3rd 2009, CPMB&B, TNAU presentation
Marker assisted selection( mas) and its application in plant breedingHemantkumar Sonawane
Marker Types,Prerequisites for efficient marker-assisted breeding programmes,Advantages of MAS,Limitations of MAS ,Marker Assisted Breeding Schemes,• 1. Marker- assisted backcrossing,2. Marker- Assisted evaluation of breeding material,3 Gene pyramiding,4. Early generation selection ,Combined approaches,MAB: I level of Selection – FOREGROUND SELECTION,Second level of selection: Recombinant Selection,MAB: III Level of Selection BACKGROUND SELECTION,
Revitalizing Marginal Lands: Discovery of Genes for Tolerance of Saline and P-Deficient Soils to Enhance and Sustain Productivity
Ismael Abdelbagi, IRRI
GCP Project G3005.02: Progress and expected impacts of Saltol and Pup1 QTLs on rice improvement
6th Asian Crop Science Association Conference and the 2nd International Conference on Rice for the Future, organised by BioAsia in Bangkok, Thailand
November 2007
By A.M. Radanileson, O. Angeles, T. Li, A.K. Rahman, D. Gaydon
Revitalizing the Ganges Coastal Zone Conference
21-23 October 2014, Dhaka, Bangladesh
http://waterandfood.org/ganges-conference/
Effect of salinity on seedling growth in early vegetative phase of riceSohel Rana
The aim of this investigation was to analyze genotypic variations of salt tolerance of rice varieties at germination and seedling growth of early vegetative phase of rice.
Development of First Multiparent Advanced Generation Inter-cross (MAGIC) Popu...ICRISAT
Pigeonpea is the sixth most important legume crop in the world and it is a rich source of proteins. Conventional methods of breeding varieties with higher yield and inbuilt resistance are time consuming and cumbersome process. Molecular breeding with the help of genome wide sequence information will be helpful in achieving the goal in less time with high precision.
24 June 2015
MAGIC :Multiparent advanced generation intercross and QTL discovery Senthil Natesan
MAGIC or multiparent advanced generation inter-crosses is an experimental method that increases the precision with which genetic markers are linked to quantitative trait loci (QTL). This method was first introduced by (Mott et al., 2000) in animals as an extension of the advanced intercrossing (AIC) approach suggested by (Darvasi and Soller , 1995)for fine mapping multiple QTLs for multiple traits. Advanced Intercrossed Lines (AILs) are generated by randomly and sequentially intercrossing a population initially originating from a cross between two inbred lines.
MAGIC involves multiple parents, called founder lines, rather than bi-parental control. AILs increase the recombination events in small chromosomal regions for the purpose of fine mapping. These lines are then cycled through multiple generations of outcrossing. Each generation of random mating reduces the extent of linkage disequilibrium (LD), allowing the QTL to be mapped more accurately.
Salinity tolerance and breeding strategies on soybeanBishnu Adhikari
Introduction
Physiological effects
Salt tolerant varieties of different crop
Important genes mapped in soybean
Salinity condition in Korea
Breeding strategy for salinity tolerance in soybean
During the Bayer CropScience Annual Press Conference on September 17 2014, CEO Liam Condon provided journalists from all over the world with a perspective on global trends in the agricultural markets, and reported on the company’s business and financial performance.
Development of transgenics for the abiotic stress tolerance is the need of the hour as the existing plant types were prone to vagaries of climate change and therefore a new technology for the development of abiotic resistant varieties through genetic manipulation is imperative.
Breeding for yield potential and stress adaptation in riceAshish Tiwari
With resources such as land being limited, increasing yield potential holds an important place for feeding the growing population. Stress is one of the main reasons for hindering the full flourish potential of any crop. Thus, breeding for increasing yield potential as well as stress adaptability goes hand in hand. Various conventional as well as advanced breeding methods along with the understanding of crop physiology can help us achieve the goal
Effect of nitrogen and phosphorus amendment on the yield of a Chlorella sp. s...Agriculture Journal IJOEAR
Abstract— A strain of microalgae was isolated from phytoplankton samples collected from the sea coast of Amsheet, North Lebanon. Molecular diagnosis based on ribosomal RNA genes showed it to be most closely related to Chlorella sp. (GenBank accession KC188335.1) with over 90 % nucleotide identity. It was then evaluated whether N and P amendments of seawater fertilized with Guillard’s f/2 medium would improve algal growth and production. Addition of nitrogen (30 ppm) and/or phosphorus (2 ppm) to microalgae grown under laboratory conditions in 3L bioreactors resulted in improved biomass yield (mg dry matter/ L) by approximately 48%, and increased protein yield by approximately 56%, from 19.5% to 30.6% of DM content. Total protein yield/L of culture medium was therefore increased by approximately 83%. Total lipid content and carotenoid levels of the microalgal culture were not affected by the N+P amendement, whereas chlorophyll content was almost doubled. When lower levels of N+P supplementations, 10 and 20 ppm N, were tried, the biomass yield was also improved. The experiment was repeated in 20 L bioreactors in a plastic greenhouse, under normal environmental conditions, with an average temperature of 28°C and a maximum temperature of 36°C. At these relatively high temperatures, the growth rate was slowed down, but N supplementations at 10 and 20 ppm resulted in improved dry matter yield by 25 and 45% respectively, and protein content by 17 and 35%, respectively. Knowledge of the optimal culturing conditions of this local Chlorella strain is essential for its efficient production and is expected to serve future environmental and biotechnological purposes.
Transgenic approaches for abiotic stress tolerancePritish Swain
Drought, salinity, high temperature, and low temperature all have a significant impact on plant growth and productivity, resulting in yield losses. Because of climate change and environmental degradation, these stresses have become a major challenge for global food security. Traditional breeding methods have had limited success in producing plants with improved stress tolerance. Transgenic approaches, on the other hand, have provided an alternative and effective means of improving plant tolerance to abiotic stresses.
Transgenic plants are created by genetically modifying plants by inserting foreign genes into the plant genome. Specific traits encoded by the introduced genes can improve plant growth and tolerance to abiotic stresses. These genes can come from other plant species as well as non-plant organisms. Several genes that play critical roles in increasing plant tolerance to abiotic stresses have been identified and characterized.
Overexpression of genes encoding osmoprotectants like proline and glycine betaine, for example, has been shown to improve plant tolerance to drought and salinity and overexpression of genes encoding antioxidant enzymes such as superoxide dismutase and catalase improves plant tolerance to oxidative stress. Another strategy involves manipulating signaling pathways that control plant responses to abiotic stresses. for example, Overexpression of genes encoding transcription factors such as DREB and Cnb-1 has been shown to improve plant tolerance to drought, salinity, and cold stress. These transcription factors control the expression of genes involved in stress tolerance, such as those encoding for osmoprotectants and antioxidants.
The use of transgenic approaches has shown great potential for improving plant tolerance to abiotic stresses. For example, the development of drought-tolerant rice has been achieved through the overexpression of genes OsNAC9 for root development. A1b regulates the HSP in wheat which helps in heat stress tolerance.
In conclusion, abiotic stress tolerance is an important trait for plant growth and productivity, particularly in the face of climate change and environmental degradation. Transgenic approaches have proven to be an efficient way of increasing plant tolerance to abiotic stresses. These methods entail inserting foreign genes into plant genomes, which can improve plant growth and stress tolerance. While there are some reservations about using transgenic plants, the benefits of improved stress tolerance for agriculture and food security cannot be overlooked. To ensure safe and sustainable agricultural practices, it is critical to continue developing and deploying transgenic plants with effective biosafety protocols.
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.
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 .
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Richard's entangled aventures in wonderlandRichard 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.
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.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
2. Flooding is one of the most important environmental stresses
worldwide
Flash flooding adversely affects at least 16 % of the rice lands of the
world (Khush, 1984)
In the rainfed lowland areas of eastern India, submergence is the third
most important limitation to rice production (Widawsky and O'Toole,
1990)
Complete submergence due to frequent flooding adversely affects
plant growth and yield
The problem
3. Rice is the only crop plant adapted to aquatic environments
because of its well-developed aerenchyma tissues
However, complete submergence due to frequent flooding can
adversely affect plant growth and yield
Two types of flooding cause damages to rice:
Flash flooding
Deepwater flooding
Submergence tolerance is required in rainfed areas
The problem
4.
5. Carbohydrate concentration
• A strong positive correlation
• Influenced by growth conditions before submergence
• Level of carbohydrates remaining after submergence is more critical
Alcoholic Fermentation (AF)
• Major metabolic adaptation
• ATP produced by this process is very small (5%)
Experimental observations (Fukao et al. 2006):
(1) Enzymes of AF often increase under flooding
(2) Hypoxia pretreatment increased tolerance
(3) Mutants lacking ADH die more quickly
(4) Rates of AF are related to the tolerance
(5) High sugar supply improved survival
PHYSIOLOGY OF SUBMERGENCE
TOLERANCE
6. Stem elongation
• A strong negative correlation
• Sensitive cultivars survived on application of a gibberellins biosynthesis
inhibitor, paclobutrazol
• Addition of GA reduced survival of submergence tolerant lines
Aerenchyma Formation
PHYSIOLOGY OF SUBMERGENCE
TOLERANCE
Fig. 2: Diffrences in formation of lysigenous aerenchyma and patterns of radial O2 loss (ROL)
in rice roots under drained soil conditions & waterlogged soil conditions, Nishiuchi et al., 2012
7. Post Submergence Events
• High light intensity and higher oxygen levels
• Generation of reactive oxygen species and toxic oxidative products as
acetaldehyde
• Two mechanisms:
Presence of natural antioxidants: ascorbate, α-tocopherol, carotenoids,
glutathione etc.
Presence of antioxidant enzyme systems: superoxide dismutase,
catalase, peroxidase etc.
Role of Ethylene generated during submergence
• Submergence-intolerant cultivars usually showed increased levels of leaf
chlorosis
• Ethylene produced during submergence trigger leaf senescence
• This was proved by using an ethylene inhibitor, 1-methyl cyclopropene (MCP).
PHYSIOLOGY OF SUBMERGENCE
TOLERANCE
8. Two distinct strategies of
growth controls –
Quiescence strategy
(Colmer and Voesenek 2009)
Escape strategy
(Bailey-Serres and Voesenek
2008; Colmer and Voesenek
2009)
Both strategies depend on
ethylene- responsive
transcription factors
Fig. 3: Strategies of adaptation to excess water stresses in the
form of submergence or waterlogging, Nishiuchi et al., 2012
9. Xu et al. (2006) discovered SUB 1
locus contains-
SUB 1 A, SUB 1 B & SUB 1 C
All encode ethylene responsive factors
Upregulated under submergence
But only SUB 1 A confers flash flood
tolerance
Reason:
Restricted shoot elongation
Supresses expression of α-amylase &
sucrose synthase and regulates alcohol
fermentation (Fukao et al., 2006)
Enhances expression of SLR1 & SLRL1
(Fukao et al., 2008) and genes involved
in ABA-mediated accimation
Reduces accumulation of ROSFig.4: Schematic representation of
Sub 1 locus (Fukao et al. 2006, Xu et
al. 2006)
Fig.4: Schematic representation of
Sub 1 locus (Fukao et al. 2006, Xu et
al. 2006)
Sub 1 gene cluster and how it works
10. Introgression is the movement of a gene from donor to recipient
parent by the repeated backcrossing of an F1 hybrid with one of its
parent.
Purposeful introgression is a long-term process
WILD RELATIVE
CULTIVAR
11. (1) LEAF TISSUE
SAMPLING
(2) DNA EXTRACTION
(3) PCR
(4) GEL ELECTROPHORESIS
(5) MARKER ANALYSIS
Overview of ‘Marker Genotyping’Overview of ‘Marker Genotyping’
12. MAB has several advantages over conventional backcrossing:
Effective selection of target loci
Minimize linkage drag
Accelerated recovery of recurrent parent
Plants with desirable genes/QTLs are selected and alleles can be
‘fixed’ in the homozygous state
plants with undesirable gene combinations can be discarded
1 2 3 4
Target
locus
1 2 3 4
RECOMBINANT
SELECTION
1 2 3 4
BACKGROUND
SELECTION
TARGET LOCUS
SELECTION
FOREGROUND
SELECTION
BACKGROUND SELECTION
Marker-assisted backcrossing (MAB)
13. Selection for target gene
or QTL
Useful for traits that are
difficult to evaluate
Also useful for recessive
genes
1 2 3 4
Target
locus
TARGET LOCUS SELECTION
FOREGROUND SELECTION
14. Use of flanking markers to select
recombinants between the target
locus and flanking marker
Linkage drag is minimized
Require large population sizes
--depends on distance of flanking
markers from target locus
RECOMBINANT SELECTION
1 2 3 4
15. Use of unlinked markers to
select against donor
Accelerates the recovery
of the recurrent parent
genome
Savings of 2, 3 or even 4
backcross generations may
be possible
1 2 3 4
BACKGROUND SELECTION
16. Conventional backcrossing
Marker-assisted backcrossing
F1 BC1
c
BC2
c
BC3 BC10 BC20
F1
c
BC1 BC2
TARGET
GENE
TARGET
GENE
Ribaut, J.-M. & Hoisington, D. 1998 Marker-assisted selection:
new tools and strategies. Trends Plant Sci. 3, 236-239.
Markers can be used to greatly minimize the amount
of donor genome
17.
18. Donors: Two breeding lines derived from FR13A i.e. IR49830 and IR40931
Recipient parents:
Samba Mahsuri and CR1009 from India
IR64 from the Philippines (IRRI)
Thadokkham 1 (TDK1) from Laos
BR11 from Bangladesh
Strategy employed to transfer the tolerant Sub1 allele into the mega
varieties
closely flanking markers used for recombinant selection to reduce the target
introgression size
background markers used to select for recurrent parent alleles
The fully converted Sub1 lines were selected at the BC2F2 or BC3F2
generation
22. All Sub1 varieties had significantly higher survival rates compared
with the original recipient parents
IR 64- Sub 1, TDK1-Sub1 and CR1009-Sub1 showed the same high
level of tolerance
Whereas BR11-Sub1 was slightly less tolerant
Samba Mahsuri-Sub1 was the least tolerant among all the Sub1 lines
The heterozygous plants of F1 hybrids of IR64/IR64-Sub1 were
significantly less tolerant than the plants homozygous for the tolerant
allele
Findings:
23. During submergence increased ethylene levels trigger accumulation
of Sub 1 A transcripts
During submergence, transcription of both Sub 1 A & Sub 1 C is
strongly up regulated and down regulated upon desubmergence
Sub 1 A down regulates Sub 1 C (Xu et al.,2006)
24.
25. More submergence tolerant
No negative side effect in terms of yield
and grain quality when grown under
control Conditions
Starch and soluble carbohydrate levels
declined more slowly
mRNA levels coding for α-amylases and
sucrose synthases were lower
Pyruvate decarboxylase (PDC) and
alcohol dehydrogenase (ADH) activity
was increased
Ethylene production was lower
Transcription of expansin genes was
suppressed
Fig.: Sub 1 confers tolerance to M2O2, a
submergence intolerant japonica rice
variety
Findings
26. Sub1A is confirmed as the primary contributor to tolerance, while
Sub1C alleles do not seem important
Lack of dominance of Sub1 suggests that the Sub1A-1 allele should
be carried by both parents for developing tolerant rice hybrids
Sub1 could be solution for providing a substantial enhancement in
the level of tolerance of sensitive mega varieties
With the identification of physiological traits, DNA markers and
genes associated with submergence tolerance the prospects for
breeding suitable rice cultivars for rainfed lowlands have been
improved
Summary &
conclusion