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Genomics and Applied Biology
, 2012, Vol.3 No.2 8-21
h http://gab.sophiapublisher.com
A Review Open Access
Exploring Plant Proteinase Inhibitors
Chumki Bhattacharjee
1
,
Doddananjappa Theertha Prasad
2
, Nagenahalli Huchappa Manjunath
3
,
Debarshi
Sanyal
4
, Sajad Majeed Zarga
5
1. Biochemistry Department, Garden City College, 16th KM, Old Madras Road, Bangaluru, 560049, India
2. Department of Biotechnology, University of Agricultural Sciences, GKVK, Bangaluru, 560065, India
3. Biochemistry Division, Department of Chemistry, Central College Campus, Bangalore University, Bangaluru, 560001, India
4. IHMA, Thanjavur, 613001, India
5. School of Biotechnology, SKUAST-J, Chatha, Jammu, 180009, India
Corresponding author:
Authors
Genomics and Applied Biology 2012, Vol.3 No.2 doi: 10.5376/gab.2012.03.0002
Received: 10 Jul., 2012
Accepted: 28 Jul., 2012
Published: 10 Aug., 2012
Copyright
© 2012 Chumki et al., This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
Chumki et al., 2012, Exploring plant proteinase inhibitors, Genomics and Applied Biology, 2012, Vol.3 No.2 8-21 (doi: 10.3969/gab.2012.03.0002)
Abstract
Proteinase Inhibitors (PIs) are small, natural antagonists of proteinases and present in all life forms. PIs are widely present
in plants and often found in storage organs. They are known to be inducible in plants by injuries, such as insect damage. PIs have
enormous diversity of function through regulation of target proteinases. Various plant sources have been explored for isolating PIs
and broad-spectrum of biological activities have been elucidated. A range of strategies have been attempted to improve effectiveness
of proteinase inhibitors as antimetabolites towards insects, bacteria and fungi. Much emphasis is yet to be given to address the health
benefits of the PIs and implementing it in the most available forms throughout.
Keywords
Serine proteinase inhibitor; Trypsin inhibitor; Insect pest; Cloning
Plants are continuously exposed to insect pest and
pathogen attacks during their life cycle. Like animals,
plants cannot move away from an endangering
environment nor do they possess a characteristic
immune system. Each plant species or cultivars have
developed diverse defense mechanism, which includes
both specific and general defense responses.
Herbivorous insects, mites and nematodes are major
contributors to yield loss either directly through
consumption of plant biomass or indirectly as
vectors/facilitators of pathogen infection. Consequently,
introgression of insect-pest resistance into crops has
become one of the major priorities for plant breeders.
Resistant cultivars reduce dependence on insecticides
and need for crop rotation, provide economic benefits
without compromising the environmental stewardship.
Studies on host plant resistance reveal that plants have
evolved natural defense strategies against pests,
including the production of compounds that contribute
directly or indirectly, protection against herbivore
invasion. The best-known plant substances
supposedly involved in defense mechanisms against
phytophagous insects are ribosome-inactivating
proteins (RIPs), protease inhibitors (PIs), amylase
inhibitors (áAl-I) and lectins. Insects have
developed several strategies to overcome plant
defense barriers, allowing them to feed, grow and
reproduce on their host plants. However, insects
possess a powerful assemblage of enzymes that
constitute their defense against chemical toxicant
(Ryan, 1990; Smith and Boyko, 2006).The major
digestive proteases present in herbivorous insect gut
are serine, cysteine, and aspartyl proteases. Inhibitors
of these proteinases have been identified in plants that
inhibit gut proteolytic activity, and adversely affect the
growth and development of insect pests. Studies
reveal that PIs are induced under various stress
conditions such as insect attack, mechanical wounding,
pathogen attack and exposure to UV. Role of PIs in
plants as natural defense has greatly stimulated
thinking towards enhancing the plant defense against
insect pests through genetic engineering. The strategy
to improve plant defenses against insect pests is being
tried using serine proteinase inhibitors. Evolutionarily
during plant–insect interactions, insects have adapted
to the PIs of their host plants. Therefore, non-host
plants were also evaluated and subsequently used for
transferring these traits into commercial cultivars.
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