National Research Centre on Plant Biotechnology

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Unraveling molecular processes involved in
adventive polyembryony towards genetic
engineering for fixation of heterosis
A subproject under Component 4 of National
Agricultural Innovation Project (Indian Council
of Agricultural Research)
National Research Centre on Plant
Biotechnology Indian Agricultural Research
Institute Campus New Delhi 110012   National
Bureau of Plant Genetic Resources New Delhi
110012   Institute of Himalayan Bioresources and
Technology, Palampur, Himachal Pradesh  
National Research Centre on Medicinal and
Aromatic Plants Anand, Gujarat- 387310  
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The overall objective of the National
Agricultural Innovation Project (NAIP) of Indian
Council of Agricultural Research (ICAR) is to
facilitate an accelerated and sustainable
transformation of the Indian agriculture, so that
it can support poverty alleviation and income
generation through collaborative development and
application of agricultural innovations by the
public organizations in partnership with farmers,
the private sector and other stakeholders. The
objective of the NAIP under the Component 4 is to
build capacity to undertake basic and strategic
research in frontier areas of agricultural
sciences and also generate basic information on
some of the fundamental processes relevant to
agriculture. Present project is funded by the
NAIP to undertake basic studies on polyembryony
with an ultimate aim to fix heterosis.
In the current scenario of limiting land and
other vital resources, productivity enhancement
appears to be the only option available for
meeting food demands of the future. Production of
hybrids in crops like rice, corn, pearl millet,
sunflower, cotton and several vegetable crops
amply testify the importance of heterosis
breeding in increasing the productivity of crops,
but various technical constraints limit the
exploitation of heterosis breeding in several
other crops. Moreover, hybrids seeds are
expensive and need to be purchased every time
making it beyond the reach of resource-poor
Indian farmers. It is widely believed that any
technology that can fix heterosis has the
potential to usher in another green revolution.
Apomixis is an asexual mode of reproduction
through seeds where embryos develop
parthenogenetically from unreduced egg and are an
exact genetic replica of the mother. Thus if
apomixis is engineered into crops, heterosis can
be fixed directly. Apomixis, however, could not
be exploited so far mainly because of very
limited understanding of apomixis at molecular
level.
At present, the world over efforts are directed
at understanding molecular basis of gametophytic
apomixis. Gametophytic apomixis involves a major
shift in the normal reproductive process to
generate genetically identical progenies. The
uniqueness of the present project is its focus on
an alternate route of apomixis via polyembryony.
In apomictic polyembryony multiple genetically
identical embryos are produced in a seed directly
from somatic cells. In majority of such cases
(e.g. citrus) polyembryony occurs in addition to
the normal sexual hybridization. Thus,
polyembryony being an add-on feature could
perhaps be more amenable for genetic engineering.
Estimated cost of the project Rs. 606.97 lakhs
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• OBJECTIVES
• Identification and characterization of nucellar
  tissue-specific genes and
• promoters of Arabidopsis.
• 2. Confirmatory survey of citrus to identify
  plants showing mono- or
• polyembryony.
• 3. Survey of guggul to identify plants
  reproducing through apomictic or sexual
• pathways.
• 4. Identification of molecular markers associated
  with polyembryony in citrus
• and guggul.
• 5. Identification and cloning of genes
  specifically expressed during initiation and
• development of asexual embryos/seeds in citrus
  and guggul.
• 6. Induction of polyembryony by nucellar specific
  expression of candidate genes.

• The project aims at identification of genes and
  promoters involved in adventive embryony with
  emphasis on the following
• Identification of monoembryonic genotypes in
  citrus.
• Identification of sexual types in guggul.
• Identification of promoters specifically
  expressed in the nucellus.
• Identification of genes specifically expressed
  during adventive polyembryonic development in
  citrus and guggul.
• Engineering polyembryony through induction of
  adventitious embryos from nucellar cells in
• vivo.

• Output
• GFP tagged promoter trap population of
  Arabidopsis for identification of novel plant
  promoters, and would serve as important tools for
  crop manipulation.
• Molecular markers associated with adventive
  embryony in citrus and guggul.
• Genes specifically expressed during adventive
  embryony in citrus and guggul.
• Nucellus specific promoter.

• Expected output and impact of the project
• Critical information on genes and promoters
  related to apomictic development in citrus and
  guggul
• Identification and characterization of nucellar
  specific promoters
• The project will pave the way towards breeding of
  apomictic hybrids across crop species
• Populations of GFP-tagged Arabidopsis is an
  important resource for all the plant biologists

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Consortium Partners
Consortium Advisory Committee
Prof. J. P. Khurana, Dept. of Plant Molecular
Biology, University of Delhi South Campus, New
Delhi (Chairman) Prof. B. D. Singh, School of
Biotechnology, Banaras Hindu University,
Varanasi, Uttar Pradesh (Member) Prof. D. R.
Sharma, Director Research, University of
Horticulture and Forestry, Solan, Himachal
Pradesh (Member )