This document discusses plant biotechnology and genetically modified organisms. It describes how plant biotechnology can be used to develop genetically modified plants with improved traits like increased yield, quality, and disease resistance. It provides several examples of how specific crops have been genetically engineered for resistance against certain pathogens. While acknowledging these benefits, it also outlines some of the objections that have been raised against genetically modified organisms, including concerns about their impact on the environment and human and animal health.

1. BARAKAT, 2019

2. Plant biotechnology
the promise and the objections
 Plant biotechnology can be defined as the use of tissue
culture and genetic engineering techniques to produce
genetically modified plants that exhibit new or
improved desirable characteristics.
 The desirable characteristics include, among others,
better yields, better quality, and greater resistance to
adverse factors, including diseases, pests, and
environmental conditions such as freezes, drought,
and salinity. Plant biotechnology also makes possible
the production in plants of useful proteins coded by
microbial, animal, or human genes.

3.  Plant biotechnology has shown that all of these goals
are attainable, at least in the kinds of plants on which
they have been attempted.
 The number of crop, ornamental, and forest plants
that have been modified genetically and released by
university and industry scientists around the world is
in the thousands and continues to grow.

4.  There are numerous cases in which plant
biotechnology is used successfully to produce crop
plants that avoid or resist certain plant pathogens.
 Some plants have been rendered resistant to specific
pathogens by genetically engineering (transforming)
them with isolated specific genes that provide
resistance against these pathogens.
 Transformed plants become resistant by coding for
enzymes that mobilize other enzymes that carry out
numerous defensive functions, such as breaking down
the structural compounds of the pathogen.

5.  Several of the enzymes produce compounds in the plant
that are toxic to or otherwise inhibit the growth and spread
of the pathogen both through the plant and to other plants.
 Other plants have been transformed with animal (mouse)
genes that code for antibodies (plantibodies) against a coat
protein of the pathogen. Genetic engineering has been
particularly effective in producing plants resistant to
viruses by incorporating viral genes in the crop plants that
code for virus coat protein, for altered movement protein,
or by incorporating in the plant noncoding segments of
virus nucleic acid or even segments of the nonsense strand
of the virus nucleic acid.

6.  Many of these crop plants have been tested for
resistance in the field with excellent results. Practical
examples of successful genetic engineering of disease-
resistant plants include melon, squash, tomato,
tobacco, and papaya crops that are protected from a
variety of viral diseases.
 The success of genetically engineered papaya for
resistance to papaya ring spot virus has saved the
papaya as a crop in Hawaii and in the Far East.

7.  Numerous other cases are still under development. For
example, engineering tobacco with a chimeric
transgene containing sequences from two different
viruses (turnip mosaic and tomato spotted wilt)
resulted in new plants resistant to both viruses.
 Similarly, engineering tomato plants with a truncated
version of the gene coding for the DNA replicase of
one of the very destructive geminiviruses resulted in
plants resistant not only to the virus from which the
transgene was obtained, but also to three other viruses.

8.  In other work, potato plants engineered with a
chimeric gene encoding two insect proteins exhibiting
antimicrobial activities showed significant resistance
to the late blight oomycete and their tubers were
protected in storage from infection by the soft rot-
causing bacteria.

9.  In other work, raspberry plants engineered with the
gene coding for the common plant polygalacturonase-
inhibiting protein (PGIP) became resistant to the gray
mold fungus Botrytis cinerea, although the transgene
in raspberry, but not in otherplants, is expressed only
in immature green fruit. In addition to helping us
engineer plants resistant to disease, molecular biology
and biotechnology have made possible the
development and use of nontoxic chemical substances
that, when applied to plants externally, stimulate the
plants and elicit the activation of their natural defense
mechanisms, i.e., activation of the localized defense
mechanism (hypersensitive response) and systemic-
aquired resistance (SAR).

10. Messenger® mode of action.
A. Messenger is sprayed onto the plant.
B. Harpin protein, the active ingredient
in Messenger®, is recognized by
receptors.
C. The plant initiates and amplifies a set
of complex signaling pathways, causing
natural gene expression.
D. This natural process results in
activation of plant defense systems,
increased nutrient uptake and
photosynthesis, improving crop yield
and quality.

12.  University have demonstrated that harpin has an
ability to improve growth as evidenced by one or more
of the following:
 increased photosynthesis
 increased nutrient uptake
 increased biomass
 increased root development
 increased seed germination
 earlier flowering
 improved fruit development
 earlier fruit maturation

13. Mode of action - Actigard

14. Genetically Modified Organisms
(GMO)
 That type of publicity has, in turn, led many large buyers to
refuse to buy and use products produced by genetically modified
organisms (GMO). Following the adverse publicity, several
governments, especially in Europe, passed laws and raised
barriers to the importation of products derived from genetically
modified organisms. In addition to the argument against
introducing into crops, through genetic engineering, new
proteins that may cause allergic reactions in some people, there
have also been arguments against biotechnology because it takes
possession of, patents, and monopolizes genetic material that
was previously available and free to everybody; it replaces the
numerous sustainable local varieties with a few genetically
engineered ones, the seed of which the farmers must buy from
large companies every year; i

15.  it threatens the development of pests and pathogens that
can resist or overcome the transformed resistant crops; it
threatens to lead to the use of larger amounts of herbicides
with crops like those made herbicide resistant while the
weeds are still susceptible; it threatens unknown numbers
of nontarget organisms that may be affected adversely by
the protein; it threatens to upset the plant balance, and
through it the entire biotic balance of the environment, by
having such new genes transferred naturally to nontarget
plants and their proteins, harmless or not, consumed by
microorganisms, animals, and humans unaccustomed to
such proteins; it threatens the occurrence of accidents in
which crops transformed for the production of
pharmaceuticals, vaccines, and so on become mixed with
edible crops.

16. Food safety
 In recent years, food safety has been threatened by a
number of events and developments that allow
foodborne microorganisms pathogenic to humans,
e.g., the bacteria Salmonella, Listeria, Escherichia coli
strain 0157:h17, the protozoa Cyclospora,
Cryptosporidium, and Giardia, and the hepatitis A
virus, to reach and contaminate our food in a variety of
ways.

17.  These include
 (a) increased processing of fresh plant produce (e.g.,
fruit juices, fruit or vegetable purees, coleslaw, fruit
sections and cut-up vegetables for salads in bulk or in
plastic bags) that may sometimes contain produce that
carries a significant amount of food-spoiling bacteria
and mycotoxin-producing fungi;

18.  (b) inadequate food processing procedures that allow
survival of human pathogens in the processed
product;
 (c) long storage of foods that encourages the
development of pathogenic microorganisms;
 (d) application to fruit and vegetable fields of
improperly aged or poorly treated manure that carries
human pathogens;

19.  (e) application on the plants of irrigation water that
may be carrying one or many of the aforementioned
human pathogens due to contamination by humans
and animals through run-off of waste waters, etc.;
 (f) unacceptable hygiene of harvesters, handlers, and
packers after using the toilet that results in the
contamination of fruits and vegetables with human
pathogens;

20.  and (g) the presence of pets, livestock, and wildlife
animals, some of which may carry human pathogens
on their bodies or in their feces to fruits and
vegetables.
 Not only is it costly to take all measures necessary to
secure food safety, but there is also the fear and cost of
rejection of produce shipments at the point of
destination. Similarly, there is the possibility of refusal
of buyers to purchase produce from farms that do not
meet the buyer’s food safety standards.

21.  . In the United States and other developed countries,
many of the large buyers of food products for their
mills, processing factories, or chain stores demand
third party audits of farms by certified specially
trained individuals and consulting firms regarding the
employment by the farm of all necessary precautions
in the type of manure they may be using, the quality of
water used for irrigation, the health and hygiene of
their workers and plant handlers, and so on.

22.  Also, to avoid unjustified accusations of offering
contaminated produce, farmers are or will soon be
expected to have a traceback system in place.

23. Bioterrorism, agroterrorism,
biological warfare, etc.
who, what, why?

24.  Bioterrorism is loosely defined here as the use, or
threat of use, of biological agents, mainly pathogenic
microorganisms that could infect people and cause
disease and, thereby, instil fear and terror in all of the
populace.
 Bioterrorism may differ from biological warfare in that
the latter is usually directed against enemy armies and
its purpose is to incapacitate or kill enemy soldiers,
whereas in bioterrorism the purpose is to frighten and
terrorize civilian populations, although casualties in
large numbers may or may not occur.

25.  The most vivid example of bioterrorism occurred in
the fall of 2001 when persons in various positions in
politics and the television news media in New York
and Washington received letters through the mail
containing spores of the bacterium Bacillus anthracis,
the cause of the severe and often deadly anthrax
disease.

26.  It became apparent at the time that the perpetrators of
the anthrax bioterrorism, or others, could easily
expand to other forms of bioterrorism by either
contaminating agricultural products such as
vegetables, milk, or meat on the farm or in the store
with microorganisms pathogenic to humans, which
would scare buyers away from such products
(agroterrorism), or by spreading selected plant
pathogenic microorganisms on certain crops, e.g.,
cereals, potatoes, and corn, which they could infect
and destroy to various extents, thereby causing
devastating losses that would further increase the fear
of the people.

27.  At the same time, however, several countries have been
experimenting with and stockpiling microorganisms that
can infect and destroy important staple food crops for
certain countries, e.g., rice, potatoes, wheat, or beans,
which could affect the availability of food and thereby
survival of the people, or at least, their will to fight and
prolong the war.
 This type of agricultural biological warfare has revolved
around important pathogens of such crops, e.g.,
Magnaporthe grisea, the fungus causing the blast disease of
rice; Phytophthora infestans, the oomycete causing the late
blight of potato; and Puccinia graminis, the fungus causing
the rust diseases ofwheat and other small grains.

28.  As the specialization of crops in each area increases and as
our knowledge of diseases of such crops increases, it
becomes evident that such areas or countries become
extremely vulnerable to agroterrorism or agrosabotage.
 This happens even if, or especially if, they grow relatively
small areas of such specialty crops, e.g., bananas, citrus,
coffee, and cacao, which are the main export crop and the
main source of foreign currency for these countries. For
each area producing such a crop there are pathogens of the
crop elsewhere that, if introduced, could destroy the crop
for the year to come and, possibly, forever.