Biotechnology And Sustainable Agriculture

Green revolution and high impact agriculture have satisfied the food requirement of most of the human population as it has doubled since 1960. But increase in food productions has led to serious environmental problems, i.e., high impact agriculture is not sustainable for more than a few decades. So, more and more farmers are trying forms of agriculture that cause less environmental problems. Sustainable agriculture (or alternative agriculture of low-input agriculture) is based on beneficial biological processes and environment friendly chemicals. In sustainable agriculture, certain modern agricultural techniques are combined with traditional farming methods. Sustainable Agriculture may be simply defined as, "Agricultural methods that rely on beneficial biological processes and environment friendly chemicals rather than conventional agricultural  techniques."
In other way, Sustainable Agriculture may be defined as, "The successful management of resources for agriculture to satisfy human needs while maintaining or enhancing the natural resource base and avoiding environmental degradation".

Hence we can say, Sustainable Agriculture is not a single programme but there is a series of programmes that are adapted for specific soils, climates and farming requirements. Water and energy conservation, crop rotation, breeding of disease resistant crop plants, use of biofertilizers (BGA fertilizers mycorrhizae, symbiotic and asymbiotic nitrogen fixers, organic fertilizers, green manures), biological pest control methods and bio-pesticides or Integrated Pest Management (IPM) are practiced in sustainable agriculture.

(Bio-fertilizers and biological pest control are given separately in detail in this unit.
In addition to these practices, biotechnology also plays a promising role in sustainable agriculture. Biotechnology held the potential of marrying biology and engineering and is essentially interdisciplinary area consisting of biochemistry, molecular biology, microbiology and genetics. Plant biotechnology includes two major technologies cell, tissue and organ culture and the recombinant DNA technology/genetic engineering. Cell and tissue culture has many commercial applications which include micro propagation, haploid breeding, productions of secondary metabolites and use in production of transgenic crops or genetically modified crops. Recombinant DNA technology has two major uses namely molecular marker technology and production of genetically modified transgenic crops. In general genetic engineering promises greater productivity and more nutritious foods.

The molecular markers have been utilized in characterization, maintenance and sustainable use of PGRs, (plant genetic resources). Their main uses in plant breeding include selection of desirable plants in early segregating generations at the seedling stage and selection of diverse parents for hybridization.

The most important use of plant biotechnology has been in the production of superior transgenic crops which are having not only resistance to different biotic and abiotic stresses but are also having improved nutritional quality of food.

Using traditional breeding methods, it takes 15 years or more to introduce disease resistance genes into a particular crop plant but genetic engineering or recombinant DNA technology takes a fraction of that time in achieving the same goal. Further in this desirable genes from any organisation can be used.

Genetic engineering may produce more nutritious food plants because they would contain all the essential amino acids. Recently in 2000, an international team of scientists has successfully engineered rice grains to produce beta-carotene or vitamin A (Golden rice or miracle rice).This rice has the potential to improve world health because about half of the world's population use rice as their staple food and rice is a poor source of many vitamins including vitamin A.

Using genetic engineering,crop plants resistant to insect-pests, viral diseases, drought, heat, cold, herbicides and salty or acidic soils can be developed.

In a cross of agriculture and medicine, molecular biologists are developing GM plants ( Genetically modified plants) that give edible vaccines, e.g., antidiarrhea vaccine and cholera vaccine both contain in raw potato. Similarly, extract preventing tooth decay and a vaccine against ulcers have been obtained from GM crops. Bananas (more palatable than potato) are also being genetically modified to provide edible vaccines, Edible vaccines hold important role for developing countries as they can be grown where most needed and they will not require clean needles and constant refrigeration.

Genetically modified crops transgenic crops have already transformed agriculture and they have been grown in more than 100 million acres of farmer's fields, each in year 1999 and 2000 despite of protests and debates.

Plant genomics is the latest or new field of plant biotechnology. Under this discipline, complete genome of Arabidopsis has been sequenced and of rice is being sequenced. This will lead to find the functions of all genes (reverse genetics), which will be having a great impact in field of cytogenetics, plants breeding and plant pathology. The Knowledge from genomics research will be utilized in detection, isolation and manipulation of genes in a variety of crops and thus, novel transgenic crops will be produced. As there is a great complexity of plant system, so let us see which way the wind blows.

Thus plant biotechnology has a great potential to improve agriculture

Branches of biotechnology

Biotechnology has over many totally different branches that are referred to by dissimilar terms principally noticeable with dissimilar colours to clarify the biotechnological field that it's employed in. the bulk extensively used ones are introduced here. first of all there's the red biotechnology that's used for medical processes, like finding genetic cures by prying genomic manipulations and making organisms to provide antibiotics.


Green biotechnology is employed in orientation to agricultural method that use biotechnology.. Some samples of that might be the event of transgenic plants that ar calculated to survive beneath precise environmental circumstances. an oversized goal of the inexperienced biotechnology is to expand a lot of atmosphere friendly solutions, as an example to search out the simplest way eliminate the requirement for pesticides.

Green biotechnology that is a lot of sometimes called Plant Biotechnology could be a speedily increasing field among fashionable biotechnology. It basically involves the gap of foreign genes into inexpensively vital plant species, leading to crop improvement and also the production of novel product in plants.

The term used for producing biotechnology is white biotechnology. this kind of biotechnology is employed to decrease the prices for manufacturing industrial provides that occur once ancient processes ar used. as an example, white biotechnology will expand AN organism that's capable to provide an explicit helpful chemical by natural processes quite than by industrial ways in which it absolutely was done earlier.


The industrial biotechnology society sometimes accepts a casual divide between producing and pharmaceutical biotechnology. an example would be that of company rising plant life to provide antibiotics, e.g. antibiotic from the genus Penicillium fungi.

Some extra samples of branches of biotechnology ar blue biotechnologies that handle marine and a marine usage of biotechnology, however that's not terribly extensively used. once discussing regarding not the straight analysis a part of biotechnology then bioeconomy is employed to speak regarding the savings and also the economical edges that biotechnology brings.

Biotechnology with marine organisms, feed into cultivation, fauna and fish health, marine natural product (including medicines), biofilms, bioremediation, marine ecology and bio-oceanography and different marine product (e.g. enzymes)

Biotechnology in india

In india, biotechnology has gained momentum after 1980-85.The Indian Agricultural Research Institute (IARI), New delhi has taken  initiative in fundamental and applied aspects of molecular biology and biotechnology. Tissue culture technique and micropropagation have been  adopted for producing seedlings of horticulturally tested varieties of orchids and banana. Protoplast fusion and somatic hybridization have also been applied for producing the rare hybrids of ornaments and vegetable plants. Council of Scientific and Industrial Research (CSIR), New delhi and Indian Council of agricultural Research (ICAR) have taken keen interests towards fundamental studies in molecular biology (such as protoplast culture, tissue culture, organ culture, translation and transcription processes in prokaryotes, immobilization of plant cells, clonal propagation, etc.)

National Biotechnology Board(NBTB) has been set up for promoting research in biotechnology on the whole i.e., in microbial genetics, gene biotechnology, DNA sequencing, genome study, tissue culture, enzyme technology, fermentation technology, immunization technology, gene amplification and DNA finger-printing. In india DNA finger printing was first carried out Dr. Lal ji singh Director, centre for cellular and molecular  biology (CCMB), hyderabad. He was able to synthesize DNA probe by himself for carrying out DNA fingerprinting in india. This techique is applied for solving the complicated problems of murders (in absence of eye witness), rapes an dispute parentage.

United National Industrial Development organization (UNIDO) have taken initiatives in establishing an international  Centre for genetic Engineering and Biotechnology (ICGEB) in New delhi to provide tools and techniques for establishing modern biotechnology centres at different Universities and Institutions working in biotechnology and genetic engineering in various developing nations. Lal Bahadur shastri centre for biotechnology has recently been established at IARI, New Delhi  for basic and applied researches in non-gene and gene biotechnology in india.
Advantages of tissue culture in cell culture, organ culture, micropropagation, conservation of rare and endangered germ-plasts, protoplast culture and its use in somatic hybridization and advantages of somaclonal variations have been discussed in coming article of Plant breeding and Tissue culture. They are now widely used in pharmaceutical industries or fermentation based industries.

Gene Biotechnology

In Gene biotechnology, suitable techniques are developed to synthesis gene/s in vitro, either by chemical synthesis method (as was used by Dr. Har govind khurana for synthesizing first gene in vitro ) or by using DNA or RNA obtained from the organism themselves (i.e from natural source). It needs a well organized Molecular biology lab, with facilites of gel electrophoresis, southern blotting, autoradiography, recombinant DNA technology, gene synthesis, PCR technique, tissue culture technique, etc

Recombinant DNA technology has extensively been used for introducing genes of interferon, insulin, somatotropin, nif- genes, bt-genes, etc., in plasmid DNA obtained from suitable bacterial organisms. The recombinant DNA is then inserted into suitable host cell (bacterial cells used as cloning organism) for gene cloning (producing indentical copies of recombinant DNA). This technique has been applied for producing genetically modified or engineered bacteria carrying desired gene/s.)

Transgenic organisms or Genetically Modified (GM) organism (plants, animals or microbes) are the most valuable gifts of biotechnology as they carry desired genes. They are capable of fulfilling the food requirements of growing world populations. Recombinant DNA technology has now been used widely not only in industries or pharmaceuticals concerns but also in agriculture and environmental biology.
Non-gene biotechnology is infact dealing the modern aspects of microbiology. Microorganisms can show be exploited for producing antibiotics, antibodies and industrially important biochemicals including enzymes.It has opened the door for several industrial and agro based companies for biorevolution. Many Nobel Laureates have also offered their services to the biotechnological organizations carrying out researches in advanced microbiology and biotechnology.

In addition to these practices, biotechnology also plays a promising role in sustainable agriculture. Biotechnology held the potential of marrying biology and engineering and is essentially interdisciplinary area consisting of biochemistry, molecular biology, microbiology and genetics. Plant biotechnology includes two major technologies cell, tissue and organ culture and the recombinant DNA technology/genetic engineering. Cell and tissue culture has many commercial applications which include micro propagation, haploid breeding, productions of secondary metabolites and use in production of transgenic crops or genetically modified crops. Recombinant DNA technology has two major uses namely molecular marker technology and production of genetically modified transgenic crops. In general genetic engineering promises greater productivity and more nutritious foods.

The molecular markers have been utilized in characterization, maintenance and sustainable use of PGRs, (plant genetic resources). Their main uses in plant breeding include selection of desirable plants in early segregating generations at the seedling stage and selection of diverse parents for hybridization.

The most important use of plant biotechnology has been in the production of superior transgenic crops which are having not only resistance to different biotic and abiotic stresses but are also having improved nutritional quality of food.

Using traditional breeding methods, it takes 15 years or more to introduce disease resistance genes into a particular crop plant but genetic engineering or recombinant DNA technology takes a fraction of that time in achieving the same goal. Further in this desirable genes from any organisation can be used.

Genetic engineering may produce more nutritious food plants because they would contain all the essential amino acids. Recently in 2000, an international team of scientists has successfully engineered rice grains to produce beta-carotene or vitamin A (Golden rice or miracle rice).This rice has the potential to improve world health because about half of the world's population use rice as their staple food and rice is a poor source of many vitamins including vitamin A.

Using genetic engineering,crop plants resistant to insect-pests, viral diseases, drought, heat, cold, herbicides and salty or acidic soils can be developed.

Foods reformed by Biotech

In the last five years, the area under transgenic crops has increased enormously in USA, China and some other advanced countries. In USA, 35% of corn and 55% of all soybean planted were transgenic in 1999. As soybean and corn are used as ingredients in a wide range of food products, many foods currently contain ingredients  derived from genetically engineered or transgenic crops. The area under transgenic crops will continue to rise and thus will result in more food derived from transgenic crops. The foods derived from transgenic crops are called ' GM foods' or genetically modified foods.

Health and food safety concerns have been raised to ensure the safety of GM foods throughout the development and commercialization of transgenic crops. The main concerns  about the potential of GM foods/ crops relate to:

Increase in toxins
Introduction of allergens
Changes in levels of essential nutrients
Reduced efficacy of antobiotics
Issues of food safety from GM crops came with a 3-years study conducted by Dr. Arpad Pusztai at Rowett Research Institute, Scotland in 1999, who showed partial suppression of growth and of development of immune system in rats fed on GM potato.

Dr. March Lappe (1999) showed that certain GM foods (GM soybean ) have lower levels of vital nutrients especially phytoestrogen and isoflavones which protect the body from heart diseases and cancer.


Nordlee( 1996)  reported that Brazilnut (Bertholletica excelsa) genes in soya caused epileptic fits.similarly, Shrimp gene in strawberry induced allergic response.

During early course of development of trangenic crops, a concern was raised that transfer of antibiotic resistance transgene from plants  to pathogene in environment or in the gut of humans or animals would compromise antibiotic therapy by rendering pathogens immune to the effects of the antibiotic.

On the other hand genetically modified crops are being developed with enhanced nutritional qualities such as increased iron (Fe) or vitamin A content in edible plant parts (e.g., 'Golden rice' or 'Miracle rice' rich in vitamin A and iron). Iron fortification of rice  has been done by soybean ferritin gene.

The US food and drug Administration (USFDA) established extensive guidelines to address the concerns and ensure the safe commercial introduction  of GM crops for use in food and feed. These guidelines have been developed through evaluation of scientific data consultation with experts from around the world. Foods containing GM crops meeting the FDA guidelines are deemed to be as safe and nutritious as their non- GM counter parts already in market.

There have been debates in many countries on whether or not, it should be mandatory to label the genetically engineered food. In USA, no such mandatory lebelling has been considered necessary, unless the transgenic food or GM foods differs significantly in composition or is allergic, e.g., tomato having significantly reduced content of vitamin C should be lebelled. Similarly , tomato having a gene from peanut should disclose this as peanut contains allergens. Transgenic canola (oil seed rape ) having a gene of brazilnut (being allergenic) is considered to have no commercial utility and hence should be lebelled for consumers
GM Foods safety guidelines established using current scientific knowledge are not static and will continue to refined as new knowledge is gained in areas related to food safety .

Enzymes worn in biotechnology or r-DNA Technology

DNA ligase enzyme- A type of enzyme used to seal the cut ends of DNA  fragments. It is a type of molecular adhesive used during joining of desired gene with suitable vector DNA. DNA ligase was first discovered by Dr. Khorana from T4 bacteriophages and thus named as T4-ligase.
Endonuclease enzyme- It is a tiny biological scissor used to cut foreign DNA and plasmid DNA before they are allowed to form recombinant DNA. It occurs naturally in some bacterial cells and acts as chemical weapon against the invading bacteriophages. It cuts both the strands of double stranded DNA and occurs in solution form.
Most of the restriction endonuclease enzyme a specific palindromic sequence for producing cuts and they usually show sticky end type cutting. The existence of restriction enzyme in bacterial cells was first demonstrated by Arber. (1906) in Haemophilus influenzae and named as Hind-III .So far, over 475 types of restrictions endonuclease enzymes have isolated and identified.

Exonuclease enzyme: The enzyme which cut single strand of DNA, digesting base pairs on 5' to 3' end or at single stranded nick of a DNA strand.

Reverse transcriptase enzyme: It was discovered by Temin and Baltimore from retroviruses. Reverse transcriptase directs complementary DNA strand formation on the templates of m-RNA (RNA directed DNA synthesis or reverse of transcription process). It helps in in vitro synthesis of DNA or gene using specific m-RNA obtained from the cell. New gene can be obtained through this technique within a short duration using DNA polymerase enzyme and nucleotides of DNA molecules in triphosphate  form (dATP, dGTP, dTTp, dCTP.

S-I nuclease enzyme: It degenerates the single stranded DNA or single strand of a double stranded DNA with cohesive ends. As a result of action of S-I nuclease, cohesive ends are converted into blunt ends.

DNA polymerase enzyme: It is used for producing copies of DNA through PCR technique or replication  of DNA under usual  condition (DNA directed DNA synthesis). It was first discovered by Kornberg.

RNA polymerase enzyme: It is meant for transcription of DNA molecules, i.e, DNA directed RNA synthesis or synthesis of RNA on DNA templates. All types of RNA (m-RNA, t-RNA and r-RNA) are synthesized by DNA templates using RNA polymerase.

Crops regenerate by the help of Biotech

GENETICALLY  MODIFIED  CROPS  OR  TRANSGENIC  PLANTS /CROPS
The most important use of the  plants biotechnology  is  the production  of  superior  transgenic  crops/plants  which  are  having  not only  the  resistance  against a  variety  of  biotic  and abiotic  stresses, but also having some improved value added properties  like nutritional quality  of  food.Transgenic plants are those plants in which a  foreign  gene  has  been  introduced  and stably  integrated  into host DNA. A gene that  has transferred  using  the  tools  of  molecular biology is called  transgene. The.The transfer or introduction  of  a  foreign  gene  result  in  synthesis  of  desirable  traits like disease  resistance, insect  resistance, herbicide resistance, etc.

Transgenic  plants have now been  produced  in more  than 60 plants species (mostly in  dicotyledonous families and  in some monocotyledonous  families  also).The  first transgenic plants were  produced  in tobacco (Nicotiana tobacum).Some other higher plants where transgenic plants have been produced are petunia hybrid,Lycopersicum esculentum (tomato), solanum tuberosum (solanum) melongena (brinjal), Lactuca sativa (lettuca) ,Brassica napus (oilseed rape or canola), Glycine max (soybean), piscum sativum (pea), Beta vulgaris (sugar beet), vitis vinifera (grape),Asparagus. Secale cereale (rye), Triticum aestivum (wheat), Zea mays (maize), Avena sativa (oat) and a gymnosperm picea glaucoma (white spruce), etc.

Some of the transgenic plants have been released for commercial cultivation,e.g.,'Flavr savr' and Endless Summer' tomatoes, 'Freedom II' Squash, 'high lauric' rape and seed or canola, 'Roundup Ready' soybean. Similarly genetically engineered insect resistance potato (New leaf ), corn (Maximizer) and cotton (Boll gard), each having Bt toxin gene from B acillus thuringiensis, have been granted full registration. Transgenic plants/crops are also called genetically engineered crops or gm crops (genetically modified crops) or gmo (genetically modified organised)

Salt tolerant transgenic plants have been developed in Arabidopsis and tomato and heribicide resistance transgenic plants have been developed in maize, beet, rape, tomato, potato, tobacco, chicory and melon.

Specific gene transfer in plants is mostly done with Agrobacterium tumefaciens bacteria (causes crown gall) diseases in many dicots). The tumour causing ability resides in a plasmid called Ti plasmid of a tumefaciens. This plasmid has become important in plant breeding because specific genes can be inserted into the Ti plasmid by recombinant DNA technique and thereby changing the genotype and phenotype of the plant. A tumefaciens based gene transfer is hampered by host range  limitations.
               
Nematode resistance in tobacco plants has been brought about by RNA interference( RNAi) technique. In the technique, a complementary RNA binds to mRNA to form a dsRNA, which is unable to translate and hence the expression is blocked. Here a nematode specific gene is introduced in host plant. When this plant is infected by the nematode, the nematode specific gene is triggered and it produced a single stranded RNA which is complementary to RNA produced by the nematode is order to infect the host plant. This complementary RNA binds to the mRNA of the nematode to form a double stranded RNA that cannot be translated. Hence the nematode is unable to infect the transgenic tobacco plant.

Gene transfer can also be made directly without using biological vectors (plasmids, bacteriophages, etc.) Naked plant cells as protoplasts have been found ideal for vectorless gene transfer. Some vectorless gene transfer methods are:

a)Gene transfer using practicle bombardment or biolistics which involves directly shooting a piece of DNA into the recipient plants tissue by a gene gun. Tungsten or gold beads (which are smaller than the plants cells themselves) are coated in the gene of interest and fired through a stopping screen, accelerated by Helium, into the plants tissue. The particles pass through plant cell, leaving the DNA inside. This technique is being used in monocotyledonous and dicotyledonous plants successfully. It is relatively simple laboratory technique. The transformed tissue is selected using marker genes such as those that code for antibiotic resistance. Whole plants are then regenerated from the totipotent transformed cells in culture, containing a copy of transgene in every single cell.

b)technique
c)Macroinjection
d)Lipofection
e)Silicon carbide fibre-vortex
f)Ca-DNA co-precipitation method
g)Electroporation
h)Ultrasonication
i)UV-laser microbeam ( However, success in few systems).


Recently , transgenic plants have been explored for production of biologically active peptides and proteins (having pharmaceutical applications including use as vaccines immunomodulators , growth factors, hormones, blood proteins and enzymes).These proteins and peptides play a key role in production  of edible vaccines and antibodies , which are convenient and inexpensive for immunotherapy. An edible vaccine against  diarrhoea has been expressed in potato and against  dental caries in tobacco. Research on transgenic plant-based production  of various vaccines and antibodies is in early stages but these generate a hope towards low-cost edible vaccines and antibodies from plants.

Plant bio technologies in india have claimed the production of an edible vaccine against cholera in tomato. This tomato will be light bluish in colour and is expected to be in market in next years.

Golden rice or Miracle rice (rich in vitamin A or b-carotene and iron ) and decaffeinated coffee are also valuable achievements of gene transfer technology.

Biosafety of Transgenic plants: Nowadays, there is a debate on biosafety issues of transgenic plants. The key points are:
i. Potential of GM crops to become weeds.
ii. Opportunities of gene flow from a GM plant to other plant.
iii. Impact of growing transgenic plants on biodiversity.
iv. Capacity of pest and pathogens to adapt to the cultivation of GM crops.

Ignoring the risks involved in cultivation of transgenic crops, in China, 2300 hectares of land has been placed under transgenic crops . In india, however onlyone transgenic crop (bt-cotton) has so far been released for cultivation. Some srains of Bacillus thuringiensis produce proteins which have the property of killing certain insects. Specific by toxins genes isolated from Bacillus thuringiensis are incorporated into cotton and other crop plants. As most of the bt toxins are insect-group specific, so choice of genes depends upon the crop and the targeted pest. The bt toxin is coded by a gene called cry, Which are of different types like cry 1Ac, cry II Ab (Controlling cotton bollworms) and cry 1Ab (controlling corn borers). Recently in March 2002, Government of India has permitted the commercial cultivation of three varieties of bt-cooton, the first genetically modified crop of the country. This has been developed by MAHYCO ( Maharashtra Hybrid Seeds Company ) in collaboration with American company Monsanto. bt-cotton is resistant to Boll-worm disease of cotton.