Jacobsen, E.

Nataraja, K.N.

English

Wageningen Yield 

OPINION 
 
CURRENT SCIENCE, VOL. 94, NO. 11, 10 JUNE 2008 1365
Cisgenics – Facilitating the second green revolution in India by  
improved traditional plant breeding 
 
E. Jacobsen and Karaba N. Nataraja 
 
Safe and sufficient food production is an 
important issue in India. Development of 
improved varieties by modern plant 
breeding is crucial, especially when 
global warming, population growth, en-
vironmental stresses, diminishing land 
resources associated with increased de-
mand for quality food like healthy fruits 
and vegetables are considered as serious 
challenges in the future. To master these 
challenges, a second green revolution is 
needed in the country. During the first 
green revolution, India had taken the 
lead by translating new scientific deve-
lopments like short straw traits1. Trans-
formation of locally adapted varieties 
into short straw varieties by backcrossing 
resulted in higher yields. Nowadays, GM 
(genetically modified) varieties are 
emerging as a strong tool and promise. 
One of the major outcomes until now in 
GM technology is yield security by resis-
tance against pathogens, pests and total 
herbicides. These GM crops are at the 
moment connected with transgenes and 
worldwide such GM crops were grown 
over 120 m ha in 2007. Between 1996 
and 2006, there was about 60-fold in-
crease in the area under GM crops, sug-
gesting that crop biotechnology is one of 
the fastest adopted technologies in recent 
history2. 
Transgenes, cisgenes and  
traditional breeding  
Transgenes (hybrid) are genes originating 
from other organisms or non-crossable 
species3, which is a new source of genetic 
variation for plant breeding. In trans-
genic technology, bacterial genes coding 
for resistance to antibiotics or herbicides 
are used for the selection of transformed 
plant cells. Therefore, it is logical that 
for the introduction of these classes of 
genes, new GM regulations have been 
developed in order to master the poten-
tial risks connected with the genes.  
 Recent major developments in science, 
like genome sequencing, are being ap-
plied in crop plants like rice, maize and 
potato, and efficient gene isolation meth-
ods such as map-based cloning and allele 
mining have opened up new avenues in 
plant breeding using cloned indigenous 
genes. Natural indigenous genes, isolated 
from the crop plant itself or from cross-
able species, are now called cisgenes in 
order to distinguish them from trans-
genes4–7. The traits of these cisgenes rep-
resent the existing genetic variation 
applied in classical plant breeding. The 
use of genetic variation coming from the 
crop plant itself or from crossable spe-
cies has a long history of safe use in 
many crops. They can be used directly in 
traditional breeding programmes as a 
source of genetic variation. If the genes 
are from wild species, introgression breed-
ing and induced translocation breeding4 
combined with induced mutation breed-
ing have been developed for transferring 
the desired traits into crops. The transfer 
of desired traits in traditional breeding is 
a relatively slow process and frequently 
connected with the problem of linkage 
drag (many neighbouring donor genes, of 
which one or a few could have negative 
impact). These linkage drag problems 
can only be solved by making more 
backcrosses and simultaneously looking 
for a recombination which is uncoupling 
the desired trait from the trait with nega-
tive impact in the offspring3. The use of 
isolated cisgenes coding for desired 
traits, could solve these problems drasti-
cally. In addition, the possibility of marker-
free plant transformation, without bacte-
rial antibiotic resistance or herbicide  
tolerance genes as selection marker,  
enables the creation of clean cisgenic 
plants without transgenes8. 
Second green revolution in  
traditional breeding by cisgenesis 
Cisgenesis is better than traditional in-
trogression and translocation breeding 
because of the absence of linkage drag 
and the reduced number of steps. Domes-
tication of crop plants has diminished the 
presence of toxic components into accept-
able levels, and there is increased possi-
bility of acquiring unrelated traits/toxic 
compounds when wild species are used 
for crop improvement. In cisgenesis these 
problems can be eliminated easily and 
desired traits can be incorporated by 
gene stacking. For example, cisgenic ap-
ple varieties are being evolved by stack-
ing resistance genes from crossable 
Malus plants for durable résistance to 
apple scab3, and biotic interaction bet-
ween potato–Phytophthora infestans is 
being studied for durable resistance by 
stacking several R-genes9. Similar ap-
proach can be attempted for developing 
cisgenic crop plants for quality traits and 
biotic/abiotic stress tolerance in India. 
Cisgenesis can be applied for all domi-
nantly inherited traits. 
 A second green revolution is needed in 
India to overcome the challenges related 
to yield security, quality traits and healthy 
vegetables and fruits. Integrated gene 
management along with precision farm-
ing is suggested for evergreen agricul-
tural revolution1. We believe cisgenesis 
can open up new options for evergreen 
revolution. For many crops, including 
vegetatively propagated ones, cisgenesis 
can be used directly for the improvement 
of existing varieties, which have already 
been shown to be safe for use in the mar-
ket.  
GM-regulations 
The GM-regulations worldwide do not 
distinguish between transgenes and cis-
genes. This means that the GM-regulations 
developed for transgenes (representing 
genes from the new gene pool for plant 
breeding), are also applied for situations 
in which only cisgenes (belonging to the 
existing breeding pool with a long history 
of safe use) are used. In the EU directive 
2001/18/EC, a definition of genetic 
modification is given which in practice is 
too broad10. It includes aspects like in vitro 
fertilization, polyploidization, induced 
mutation and protoplast fusion which, 
except for protoplast fusion, have a long 
history of safe use. Therefore, in vitro 
fertilization and induced polyploidization 
techniques and their products are not 
considered as GMOs (genetically modi-
fied organisms, annex 1a; ref. 10) and 
plants generated from induced mutations 
OPINION 
 
CURRENT SCIENCE, VOL. 94, NO. 11, 10 JUNE 2008 1366 
and protoplast fusion between crossable 
species though considered as GMOs, are 
exempted from the regulation. The traits 
related with cisgenes are safe and being 
used in traditional breeding. Therefore a 
strong recommendation is made to add 
cisgenes to the list of exemptions in an-
nex 1b (ref. 10).  
 In India, the framework for transgenic 
crops is described by the Department of 
Biotechnology11, which consists of the 
following rules and guidelines: (1) 
‘Rules and Policies’ with Rules 1989 un-
der Environment Protection Act (1986) 
and Seed Policy (2002), and (2) ‘Guide-
lines’ for Recombinant DNA (1990) and 
for Research in Transgenic Crops (1998). 
For research, the recombinant DNA 
guidelines have been classified into three 
categories: Category I activities include 
those experiments involving self-cloning 
using strains and also inter-specific clon-
ing belonging to organisms in the same 
exchanger group, which are Generally 
Considered As Safe (GRAS). Category I 
experiments need only intimation to the 
IBSC and are exempted from approval of 
‘competent higher authority’. In our 
opinion, cisgenes of plants belong to the 
same category as self-cloned genes in 
microorganisms. This would mean that 
the guidelines for research in transgenic 
plants, which are normally grouped un-
der three categories (I–III), a category 0 
with cisgenes, natural indigenous genes, 
should be added with exemption of these 
genes in parallel with category I of the 
recombinant DNA guidelines. This 
would mean that in the seed policy, va-
rieties from cisgenic plants could stay 
out of the separate section (No. 6) on 
transgenic varieties. It is interesting to 
observe that in the Food Safety and 
Standards Bill of India (2005), GM food 
has been defined as the food which is 
produced through techniques in which 
the genetic material has been altered in a 
way that does not occur naturally by mat-
ing. As mentioned earlier, the cisgenic 
crop plants are highly comparable with 
traditionally bred varieties because in 
this approach no new class of genes from 
non-crossable organisms will be intro-
duced.  
Objections against exemption and 
clarification 
A few objections against cisgenesis to 
exempt them from the GM-regulation 
are: (1) the random insertion of the gene 
into the genome and (2) mutation caused 
in the plant genome. In plant breeding 
such events are not new. We know from 
induced translocation breeding by irra-
diation that a piece of alien chromosome 
containing the desired resistance trait of 
the wild species, surrounded by many 
other donor genes, is inserted randomly 
in the crop genome, and such an approach 
is employed in wheat. In crops like 
maize, transposable elements can move 
within the genome. In practice induced 
mutation breeding is safe, as illustrated 
by safe use of more than 2500 mutant va-
rieties in many different crops. The new 
GM varieties with transgenes are a good 
example of random insertion without 
problems, if selection procedures of nor-
mal breeding are applied.  
Conclusion 
The classical methods of alien gene 
transfer by traditional breeding yielded 
fruitful results. However, modern varie-
ties demand a growing number of com-
bined traits, for which pre-breeding 
methods with wild species are often 
needed. Introgression and translocation 
breeding require time-consuming back-
crosses and simultaneous selection steps 
to overcome linkage drag. Breeding of 
crops using the traditional sources of ge-
netic variation by cisgenesis can speed 
up the whole process dramatically, along 
with usage of existing promising varie-
ties. This is specifically the case with 
complex (allo)polyploids and with het-
erozygous, vegetative propagated crops. 
Therefore, we believe that cisgenesis is 
the basis of the second/ever green revolu-
tion needed in traditional plant breeding. 
For this goal to be achieved, exemption of 
the GM-regulation of cisgenes is needed.  
 
 
1. Swaminathan, M. S., Crop Sci., 2006, 
46, 2293–2303. 
2. James, C., ISAAA Briefs, No. 35 ISAAA, 
Ithaca, NY, 2006. 
3. Jacobsen, E. and Schouten, H. J., Trends 
Biotechnol., 2007, 219, 219–233.  
4. Friebe, B. et al., Euphytica, 1996, 91, 
59–87. 
5. Jacobsen, E. and Hutten, R., In Potato 
Developments in a Changing Europe 
(eds Haase, N. U. and Haverkort, A. J.), 
Wageningen Academic Publishers, 2006, 
pp. 46–57. 
6. Schouten, H. J., Krens, F. A., and 
Jacobsen, E., Nature Biotechnol., 2006, 
24, 753. 
7. Schouten, H. J., Krens, F. A. and 
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8. Vetten, de N. et al., Nature Biotechnol., 
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9. Haverkort, A. J. et al., Potato Res., 2007, 
(in press).  
10. Anon., Report, Official Journal of the 
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11. Anon., Report, Department of Biotech-
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http://dbtindia.nic.in/ 
 
 
E. Jacobsen is in the Laboratory of Plant 
Breeding, Wageningen University, 
Wageningen, The Netherlands and 
Transforum Agribusiness and Rural Areas, 
Louis Pasteurlaan 6, 2700 AB Zoeter-
meer, The Netherlands; Karaba N. 
Nataraja* is in the Department of Crop 
Physiology, University of Agricultural 
Sciences, GKVK, Bangalore 560 065, India. 
*e-mail: nataraja_karaba@yahoo.com  
 
 
 
 
 
 
 


Cisgenics - Facilitating the second green revolution in India by improved traditional plant breeding

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