Is the understanding of the genome of crop plants effective in designing drought resistant and more nutritional plants?

7/28/2019 Is the understanding of the genome of crop plants effective in designing drought resistant and more nutritional pl

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African Leadership Academy

Journal of Scientific Research2011


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Published June 2011 in Johannesburg, South Africa

About the Authors

The authors of these papers were all students at African Leadership Academy at the time that they conducted this research, wrote and presented their findings, and submitted these reports.

About African Leadership AcademyAfrican Leadership Academy (ALA) is transforming Africa by addressing its greatest need: ethical and entrepreneurial leadership. Over the next 50 years, ALA will create a network ofthousands of leaders who will work together to address Africas greatest challenges and bring about lasting peace and prosperity to the continent.


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Contents

Introduction

Species Extinction: How Much Is Left and What Are the Implications? ............................ Rose Mbaye

How Entanglement Makes the Dream of Building Nano-ultra-powerful

Computer Come True ..............................................................................................Jean Rome Malou

The Malleability of the Human Memory and the Power

of Suggestibility in Implanting False Memories ................................................... Bih-Neh Nsoh Estella

Energy From the Stars ................................................................................................... Kidus Mersha

How Impressionable Are We? The Psychology of Compliance .............................. Oluwatobi Runsewe

Space and Mars Exploration ........................................................................... Chernoh Sallieu Jalloh

Is God a Mere Philosophical Product or a Physical Entity? ........................ Yehou Michel Davy Gnopo

Is the Understanding of the Genome of Crop Plants Effective

in Designing Drought Resistant and More Nutritional Plants? .......................................Ali Baba Djire

Which Biofuels Are Most Feasible for Use in African Countries? ................................ Sandra Kimokoti

The Next Big Thing Is Small: Nanoparticles and Their

Application in Diagnosing and Curing Tumors .......................................................Abenezer Mulugeta

Technology Development for Digital Cinema (How can we virtually create

anything we can imagine?) ................................................ Mohamed ould Sidahmed ould Echkoune

Quantum Entanglement and the Possibilities of Temporal Teleportation ....................Anthony Otieno

Graphene: Current Trends and a Peek into Tomorrow ........................................... Gift Nyikayaramba

Human Commensal Bacteria: The Relationship We Share ...................................... Thatohatsi Sefuthi

Cancer and Its Cure: A Unison Cure for Cancer .................................................................. Syl Rogers

The Genetics of Infectious Disease ............................................................................... Stanley Ewala


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Introduction

The 2010-2011 school year marked the second year of the Scientific Research course at African

Leadership Academy. The goal of the course is to expose students to current research in the variousfields of science, to teach them to fully analyze and interpret joural level science writing, and to allowthem to become experts in a particular area on the frontiers of scientific knowledge. The students beganby reading widely about current developments, meeting weekly in small groups with an instructor anda few peers to share about their reading. They then focused on a topic of special interest, where theyquickly surpassed the knowledge even of the instructors, and they began to teach each other from theirfields of expertise.

This year saw explorations in a wide range of topics, from quantum dots to commensal bacteria to thepliability of human memory. Over the course of the year, students taught each other and learned from eachother through a process of review by discussions and presentations as they continued to develop theirunderstanding. At the end of the year, they compiled their research into comprehensive review paperson their field. The year culminated with the second annual Scientific Research Symposium where, forthe first time this year, each student presented a poster on their research with the wider community.

The Symposium also featured keynote addresses from Tobi Runsewe, Michel Gnopo, Sandra Kimokoti,and Anthony Otieno.

This journal is a compilation of the papers from this years of Scientific Research class. We hope youenjoy glimpsing the journey of this past year!

David Scudder, Vincent Tago, and Michael Adeleye

Instructors for Scientific Research


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Is the understanding of the genome

of crop plants effective in designing

drought resistant and more

nutritional plants?Ali Baba DjireABSTRACT

The idea of creating drought resistant plants has intrigued scientists minds for decades. Recent

studies have helped scientists to identify genes that are involved in the closure of plant stomata.These discoveries opened perspectives for scientists to investigate the design of drought

resistant plants. Even if they got to know about the implication of genes in the mechanism ofthe stomata closure, a full understanding of the way these genes operate is crucially

important for the development of drought resistant plants. From a different perspective, the

understanding of how some genes work helps scientists to develop more nutritional crops.Through biotechnological techniques they have been able to incorporate desired trait into acrops with the purpose of increasing the nutrient content. Some have already been a success, butthe most interesting part of the idea is still in trials.

Ali Baba Djire (Burkina Faso)

Ali Baba Djire is a young determined man from Burkina Faso. His passion for agriculture gave him the opportunity to

investigate some research in a horticulture laboratory in his home country. Ali Baba aspires to become an agribusiness man

and has the great vision to make hunger disappear from the African continent.Page 50 Journal of Scientific Research 2011


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INTRODUCTION

The past fifty years have been incredibly revolutionary to the application of technology in agriculture. The globalfood production dramatically increased by about 400% in to the last three decades. This massive increase was in factcharacterised by the development of the knowledge of plants genomes. Over the past five decades, scientists discovered

a lot about the role of individual plant genes and their impact on the development and the productivity of plants. Fromthe design of insect resistant crops to the improvement of the quality of seeds, scientists have been manipulating genesfor the desired traits according to the conditions. Today, the world is going through a dramatic shortage of water and

food in some areas. The pressing issue is whether the understanding of crop genomes can effectively help in designingmore drought resistant and productive crops. This issue has mobilised scientists from all over the world through longyears of research and findings.

The application of technology in agriculture is commonly known under the name of Biotechnology. Biotechnology

is a field of applied biology that involves the use of living things in engineering, technology, medicine, agriculture and otheruseful applications. Through this technique, scientists have developed over the past 15 years new types of crops calledtransgenic or genetically modified crops in order to improve crops productivity and resistance. In fact, transgenic crops arthose that carry and transmit one or more copies of a recombinant DNA sequence (i.e., a DNA sequenceproduced in a laboratory using in vitro techniques) (Adnan, 2010). Despite this great improvement, the world stillacknowledges the presence of low productivity in certain parts of the globe. The need that drives scientist is to know

how to improve water supply, seed quality and nutrient supply.

TECHNIQUES ENABLING THE IDENTIFICATION OF THE ROLE OF A GENE

The little knowledge that scientists had years ago about genes and their functions fuelled their desire to explicitly findout more about the plants genes including their locations, their roles, their period of expression, etc. For that, theyhave been using a range of methods and techniques to make this project come true. Among these we have databasesearch, expression profile and mutant library (Goff, 2004). Database search involves the comparison of a newly foundgene to the one already found. In other words, when scientists find a new sequence of a gene, they make a computercomparison with the ones they have already stored in their database. The aim of this is to check if there are anysimilarities between new gene and the one already found. For instance, of the 50,000 genes estimated in rice genome,about 20,000 are similar to the genes found in other organism and it can be inferred that they have the same functions(Goff, 2004).

Expression profile specifies the function of a gene, when and where it is activated. The process involves a microarraycontaining thousands of probes. A probe is a length of DNA that has a complementary base sequence to another piece ofDNA that we want to detect. Each probe is adapted to the activity of a specific mRNA (messenger RNA). At a

particular stage of plants growth, part of that plant is washed across the microarray. If there is any RNA, it will stick to itscorresponding probe, causing the probe to shine through the emission of light.

Finally, the most-used method is the mutant library technique, which involves the deactivation of a gene in order tofind out about the function of that specific gene. In order to do this, a piece of DNA is introduced into a gene in orderto knock out the gene during the development of the plant. Once the plants have grown, the mutant is screened for

observation of any physical or chemical difference between the norm and its mutant (Goff, 2004). The use of thesetechniques is really helpful in enabling scientists to understand the role of some genes in the development of plants.


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Images adapted from Back to the Future of Cereals byStephen Goff and John Salmeron.

DROUGHT RESISTANCE GENES

This study is going to focus particularly on two components of this question: water and nutrient supply. The pastdecade has been marked by scientists focus on developing drought resistant crops. They want to create a new varietyof crop plants that are going to use less water but have an increased yield. The discovery in this field is mainly markedby the result of the researchers at Purdue University who have found a mutation that allows plants to better endure

drought without losing biomass. Naturally, plants control the opening and the closing of their stomata for both theuptake carbon dioxide and the release of water vapor. Usually, the closing of the stomata suppresses both of theseevents. When the stomata are open, the plant releases water vapour to the atmosphere due to the water potential

gradient difference between the atmosphere and plant cells. It also releases oxygen as a waste product of photosynthesis and

absorbs carbon dioxide to carry out more photosynthesis. However, the new discovery compromised this idea(Walheimer, 2011).

The research was conducted by Mike Mickelbart, an assistant professor of horticulture; Mike Hasegawa, a professor ofhorticulture; and Chal Yul Yoo, a horticulture graduate student. Mickelbart and Yoo used an infrared gas analyzer todetermine the amount of carbon dioxide taken in and water lost in a mutant species called Arabidopsis. Carbon dioxidewas pumped into a chamber with the plant and the analyzer measured the amount left after a plant had started to take

up the gas. A similar process measured water lost through transpiration, in which water is released from a plants leaves(Walheimer, 2011).

Analysis showed that the plant, which has a mutant form of the gene GTL1, did not reduce carbon dioxide intake butdid have a 20 percent reduction in transpiration. The plant had the same biomass as a wild type ofArabidopsiswhen itsshoot dry weight was measured. Closely observed, it was also found that over 20 genes controlled the stomata function.One particular gene, known under SDD1, which is responsible for the regulation of the number of stomata in theleaves, was found to be prevalent in the mutant plants. It was also found that, in mutant plants with non-functionalGTL1, the gene SDD1 was highly expressed, resulting with the development of few stomata. This discovery wouldprobably open doors for a horizon of the designing of more drought resistant crops (Walheimer, 2011).

For further comprehension of the biology behind drought resistant plants, independent studies were carried out.

Seven genes were found to be involved in the drought resistant mechanism. These include transcription factors (e.g.CBF3), genes involved in abscisic acid (ABA) biosynthesis (e.g.NCED2, LOS5) and genes involved in oxygen-radical

d ifi i ( SOS2) F f ll d di f h h i h i d h ABA i lli


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pathway in a drought stressed conditions. It was then found that this condition triggered higher sensitivity to the ABA signal

As a result, there was a more-rapid stomatal closure, an increased water retention in the plant, and an increased seed yie

(Devine, 2010).

Questioning how to find out more about the drought resistance mechanism, another experiment revealed that a knockout of tFarnesyltransferase b subunit (FTB) which is an enzyme that enables the reaction between the farnesyl group and a proteinprotects Arabidopsis plants against drought. Knock-out is a technique that consists to inserting a smallpiece of DNA into a gene in order to silence that gene in the development of the plant. Once the plant developed,

the mutant is screened for physical or chemical difference from the normal in order to determine the role of the gene.The result of the latest experiment revealed that the knock-out plants exhibited some deleterious effects that delayedflowering and reduced yield (Devine, 2010).

Figure 1. Leaf transpiration, soil-water content, plant-water content and seed yield inArabidopsis, conferred by down-regulation of Farnesyltransferase b (YPT). Data areexpressed as percent of the parent (wild-type) control (Pei et al., 1998) (Devine, 2010)

Another observation provided an interesting insight about drought resistance. An experiment enables scientist toobserve that when a plant expresses down-regulation of the Farnesyltransferase b subunit (FTB) under the impact ofan anti-sense or RNA interference, there was the creation of a drought-resistant phenotype (Devine, 2010). Down-regulation is a process by which a cell reduces the amount of some crucial cellular components such as RNA proteindue to external pressure on the cell. As mentioned earlier, knock-out is followed by some deleterious effects of the geneswe want to test, for instance a delayed of the flowering or a reduction of the yield etc. In the case of down-regulation itwas interestingly found that, there were no such detrimental effects when knocking out genes (Devine, 2010).

Climate change is a phenomenon that affects peoples daily lives. Resources such as water are becoming scarcer at

the surface of the globe. Scientists have been worried about the adaptation of some plants such as rice which requirehigh amounts of water for their survival. Many researchers have then been undertaken in order to find a solution tothis challenge. Fortunately the incredibility of mutation appears here again as an answer to this problem. Recently,plant scientists at the University of California discovered a gene enabling rice to survive under drought conditions.In fact, this research is two dimensional. The gene that is known under the Sub1A usually controls the plant whensubmerged by water. It happens that this gene also helps the plant to endure drought (University of California, 2011).Molecular biology studies revealed that this gene in fact, draws the line between extreme drought and submersion.

The way this gene operates is not exactly clear, but it is thought that after a flood endured by the rice, it experiencesa period of dehydration in order to release the excess water in the cell. The role of the gene Sub1A is in fact expressedd ring this period While the plant end res dro ght condition Sub1A redefined its f nction to create an adaptation


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fully understood, the fact of knowing that it is involved in the adaptation of rice to drought conditions constitutes apotential means to develop drought resistant crops.

GENES AND THE IMPROVEMENT OF NUTRITIONAL VALUE OF CROPS

Discovering the role of a gene is in fact a great step toward the development of crops, but the application of thisknowledge and the implication of the decision made constitute the crucial part of the process. Having this in mind, scientistshave been working for effective impact of the knowledge of the individual genes. An important area of

concern is the nutrient content of the crops. In fact, some crops are really rich in one type of nutrient and poor inothers. While some people do rely on mainly one type of crop, it appears often difficult to receive a variety of nutrients inthe daily diet. For instance, while root and tuber crops are rich in carbohydrates, they are low in protein; legumes are usuallyhigh in protein, but deficient in essential amino acid methionine; and milled rice is rich in starch but contain little of theessential amino acid lysine, iron, and has no provitamin A (b-carotene) (Sun, 2008).

Through biotechnology, new methods were developed based on the knowledge of the genes controlling the productionof particular nutrients to increase both the productivity and provide crops with the essential amino acids (EAAs).This was done through four main techniques which are: a) modifying the protein sequence of a major crop proteinto contain higher content of a desired EAA; b) producing a synthetic protein rich in a target EAA; c) expressing aheterologous protein with high content of the desired EAA; d) manipulating the expression of a homologous protein

for desired EAA; or by increasing the pool of a specific free EAA through metabolic engineering. For example, by usingthe protein sequence modification technique, scientists inserted 4 contiguous methionines (amino acid) into soybeanglycinin (Sun, 2008). The soybean glycinin turned up to be Met-rich soybean glycinin under the control of a promotercalled Glub-1. More interestingly, a transfer of the newly formed gene into rice led to 5% increase of the total protein(Sun, 2008).

On the same note, one scientist, Kim, experienced the synthetic gene approach based on the structure of maize zeinproteins (Sun, 2008). He synthesized an artificial storage protein (ASP1) composed of 78.9% EAAs and successfullytransformed a tobacco gene known under 284bp ASP1.A close examination of the transgenic tobacco revealed thatan expression ofASP1in the tobaccos leaves. There was a relatively high level of accumulation of theASP1 protein.Further experiments have shown that the mutant protein of tobacco is passed to other generations, resulting in arelative increase of the level of amino acid and proteins. In a more recent experiment, theASP1 gene was transformedand expressed in the leaves and primary roots of cassava plants. The results revealed an increased level of amino acidcoding for the artificial storage of protein in the cassava, while the leaves had no major difference in the amino acid(Sun, 2008). These results are really important for modern agriculture because they open ways to increase the nutrientcontent in traditional food and the gene responsible for the increase protein can be passed down to other generation ofthe plant.

Other experiments based on the manipulation of homologous proteins also enabled an increase of protein contentin potatoes. Besides the methods enabling an enrichment of plants in protein, other fields of the technology makeit possible to similarly increase the amount of some nutritional molecules such as lipids, carbohydrates, ions, zincand vitamins (Sun, 2008). For instance, through transgenic technology, scientists use an innovative method calledbiofortification to increase vitamin A in rice, creating what is known as Golden Rice. Biofortification is a breeding

method of crops that enables an increase nutritional value (Adnan, 2010). On the same note, there are some promisingapproaches to eventually incorporate vitamin C, vitamin E, ions, and zinc into rice (Sun, 2008).

PROSPECTIVE POTENTIAL FINDINGS

Most of humans food comes from crops. The majority of these crops are annual plants. They need to be planted every yearusing the same resources such as land, machines, insecticides, etc. Agriculture is generally dominated by about 80% of theseannual plants (Glover, et. al., 2007). These types of crops compromise the agriculture that the human population has beenpracticing for centuries, which are perennial plants. In fact, it leads to a lot of environmentaldegradation that will probably worsen the condition of the worlds population in the long term (Glover, et. al., 2007).Theidea that comes as a panacea to this issue is the intensification of perennial crops. Perennial plants are plants which have the

capacity to live for many years, partly due to their roots being embedded deep in the soil.

Annual crops such as maize sorghum and soybean require continuous care through the supply of water and nutrients


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about 0.3 meter deep, leads to soil erosion, depletion of soil fertility and water contamination. Additionally, the short length ofthe roots makes it difficult for them to obtain sufficient water, nutrients and carbon from deeper groundlevels (Glover, et. al., 2007) Therefore, having roots that will be able to go deep into the soil might be the solution tothis problem. Researchers have shown that with deep roots, perennial crops appear to be 54 times more efficient inmaintaining the quality of the soil than those annual crops (Glover, et. al., 2007). More interestingly, talking aboutdrought resistance and the improvement of nutritional value of crops, it was documented that perennial plants cause a fivefoldreduction of water loss and about 35 fold reduction in nitrogen loss, which directly causes a net increase of the nutritionalcapacity of crops (Glover, et. al., 2007).

Perennial plants such as intermediate wheatgrass access nutrients and water in larger volumes of soil due to their bettdeveloped roots compared to annual plants, such as in winter. Moreover, perennial roots support microorganisms aother biological activity that enrich soil. The resulting dark, granular soil, taken from underneath a perennial meadoretains ample water and nutrients. Soil from an adjacent annual field is lighter with a weak, clumped structure. (Glovet. al., 2007)

Image adapted from Future Farming: A Return to Roots by Glover, et. al., 2007.

The idea of creating more nutritional and drought resistant crops is usually done by biotechnology, which is in factthe modification of genes. Some people might develop an allergy to these products. Most of the allergies are due toexpression of some new protein that plants develop in response to a foreign body (gene that has introduced into them)(Ezzell, 2003). On the same way that scientists knock genes out, they also tried to tackle the issue by knocking outsome genes that are responsible for producing protein in response to foreign bodies in the cell. For instance, AnthonyKinney, (a genetic researcher at Dupont) and his team used a method called RNA interference (RNAi) to knock out thegene responsible of the production of the protein p34, the protein responsible for causing major (65% of ) allergies tosoybeans (Ezzell, 2003).

HOW IMPORTANT ARE ALL THESE DISCOVERIES?

The activities of humans around the globe have resulted in the phenomenon known as global warming. This negativephenomenon, of which humans are the major cause, affects them in return as the running of their activities becomesdependent upon the influence of global warming. From fishing to agriculture, humans activities suffer the influence

of this dramatic change of our environment. Despite this change, men are trying to adapt themselves to the new era ofcalamity. With science as a guide, scientists are trying to rescue global agriculture from one of the main issues of globalwarming, which is drought. Current research and findings stand up in a spectacular way in the sense that they promisea future for global agriculture.

The discovery of genes such as GTL1 and Sub1A constitute an enormous step toward the development of droughtresistant plants. Looking at the irregularities of rainfall around the globe, it becomes evident that water is a scarce

resource. Farmers in developing countries who rely so much on rainfall might then suffer the vulnerability of lack ofwater. Food security might then become even worse in these regions of the world. Through the genes GTL1 and Sub

d f h t d th d l t f t f th t ill b t t i t t l th d


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The application of the knowledge of genes to the development of more nutritional plants is also amazing. Recently800 million people around the world were recorded as hungry and malnourished (Nemecek, 2001). The majority of

people who are generally malnourished are children. This is often not due to the fact that they do not get enough toeat, but rather to the fact that they consume the same crops over and over, which have a limited amount of a certainnutrient, depriving them of a variety of nutrients. Knowing what a gene codes for and transferring that gene into othercrops is in fact a huge promise to an improvement of the nutritional value to people. The vision of this technology is toincorporate a variety of nutrients that are found in different plants into a single crop. For instance, we might be able todevelop a new type of maize that is at the same time rich in carbohydrates, protein, lipid as well as vitamins.

On the economic perspective, this will be really incredibly cost efficient. Looking at the prospects of the technology,I believe that there is a lot of promise in the future of crops. At first, scientists were fascinated by the idea of creatinghigh yielding varieties of crops to increase productivity. Today, this is now part of our story. Biotechnology did not onlyhelp scientists to create plants with high yields but also to provide plants with insect, bacteria and virus resistance. Theunderstanding of the genes such as GTL1 and Sub1A are just a few samples of the variety of the genes involved in thecontrol of drought. As mentioned earlier, about seven or more genes are thought to be involved in drought resistance.

The application of biotechnology in agriculture and the discoveries made show huge potential in designing plantsthat require less water but have high yield and contain more nutrients. My vision of the future of this field is one ofspectacular accomplishments. Imagine farmers predicting the exact amount of crops that will be harvested (precisionfarming); imagine scientists designing crops that will mature in half the length of time they usually take; imaginea tree producing both mangoes and oranges. The genes that I usually call the bible of information contain all the

information that controls the development of plants. As we get to understand deeper the mechanism of these geneswe shall dive into a new generation, a generation where genes will change the nature of life and revolutionize ouragriculture.


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BIBLIOGRAPY

Adnan, Amna. Biofortification-A technique used in agriculture. Biotech Articles, 22-06-2010. Web. 14 Mar 2.

Devine, Malcom. Enhancing Crop Productivity Through Increased Abiotic-Stress Tolerance and Biomass ProductPerformance Plants Inc., n.d. Web. 14 Mar 2011.

Ezzell, Carol. Fixing Food. Biotech(2003): 24. Web. 22 Jan 2011. .

Glover, Jerry, Cindy Cox, and John Reganold. Future Farming : A Return to Roots?. Scientific American. N.p., Au2007. Web. 22 Jan 2011. .

Goff, Stephen and John Salmeron. Back to the Future of Cereals. Scientific American. N.p., August 2004. Web. 222011. .

Nemecek, Sasha. Does the World Need GM Foods?. Scientific American, April 2001. Web. 26 Feb 2011. .

Sun, Samuel. Application of agricultural biotechnology to improve food nutrition and healthcare produ

Department of Biology, the Chinese University of Hong Kong, Hong Kong, China, n.d. Web. 14 Mar 2011.

University of California. Technique allows researchers to identify key maize genes for increased yield. ScienceDaily

January 2011. 14 March 2011 .

Walheimer, Brian. Gene helps plants use less water without biomass loss. Physorg.com. Purdue University, 112011. Web. 23 Jan 2011. .

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Research 2011
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Is the understanding of the genome of crop plants effective in designing drought resistant and more nutritional plants?