Molecular Plant Breeding, 2016, Vol.7, No.16, 1-7
1
Review Ariticle
Open Access
Molecular Biology of Ethylene, a Review
Siddra Ijaz
1, 2
1 Centre of Agricultural Biochemistry and Biotechnology (CABB), University of Agriculture Faisalabad, Pakistan
2 Department of plant sciences, University of California Davis, CA,USA
Corresponding email:
Molecular Plant Breeding 2016, Vol.7, No.16 doi:
Received: 20 Dec., 2015
Accepted: 19 Feb., 2016
Published: 19 Feb., 2016
Copyright
© 2016 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
:
Siddra Ijaz, 2016, Molecular Biology of Ethylene, a Review, Molecular Plant Breeding, 7(16): 1-7 (doi:
)
Abstract
Ethylene is a plant hormone of wide-ranging diverse effects on plants physiology and development. This simple molecule
interacts with other hormones and factors with very versatile and fantastic manner for executing growth as well as developmental
events in plants. Ethylene has strong impact on myriad developmental events of plants from germination to senescence. Here intent is
to focus and highlight the importance, synthesis, regulatory genetic network and signaling integration of this versatile molecule that
affects plant growth and development in a myriad ways.
Keywords
Ethylen; Biosynthetic pathways; Ethylene signaling; Receptor; Plant physiology; Growth hormones
Introduction
Ethylene is a plant hormone and simplest unsaturated
hydrocarbon. It is a gaseous signal molecule and a
wide range of metabolic, physiological as well as
developmental events in plants is regulated by this
biologically active gas (Schaller, 2012). Ethylene has
strong impact and effect on climacteric fruits ripening
and also on triple responses in etiolated seedling of
dicotyledonous plants. Fruit ripening mechanism is a
complex and genetically programmed developmental
event. Ripening process in fruits is started from its one
sector and spreads to adjoining sector. In this process
ethylene is diffused cell to cell and thereby is
assimilated in whole fruit. This physiological event is
culminated in remarkable variations and modification
in texture, color, aroma and flavor of fruit flesh (Klee
and Giovannoni, 2011).
Ripening mechanism is different in different fruits;
therefore on the basis respiration rate and ethylene
production, these are grouped into two categories;
climacteric and non-climacteric fruits. The former
ones show rise in respiratory rate and concomitant
ethylene production at high level when they close to
maturity and edibility. At this time ethylene burst is
achieved. Thus for ripening climacteric fruits have no
need to remain attached to tree and they ripen after
harvesting such as banana, mango, apple, tomato,
papaya etc. Whereas in non-climacteric fruits such as
citrus, grapes, strawberries, and pineapple etc, no
ethylene burst is achieved at this stage and respiration
rate is at its lowest level and is continuously declined
until senescence occurs. Hence these fruits only ripen
when they are on trees or vines. In climacteric fruits,
for operating ethylene regulation, two systems have
been proposed i-e., ethylene autoinhibitory and
ethylene autocatalytic. During normal vegetative
growth, former one is functional and is also involved
in the ethylene production at basal level that are
noticed in all tissues of climacteric fruits and even in
non-climacteric fruits. While later one is operated
during climacteric fruit ripening and is also
responsible in the senescence of some petals
(Alexander and Grierson, 2002).
Pollination stimulates ethylene induction and
production in floral organ that leads to growth of
ovaries and floral senescence and abscission ((Balbi
and Lomax, 2003; Wang et al., 2005). Genes involved
in ethylene biosynthetic pathway as well as
responsible for its signaling are down regulated after
fruit setting (Pandolfini et al., 2007; Stepanova et al.,
2008) when plants are pollinated and even treated with
gibberellin. The effect of ethylene in fruit setting and
development was not under keen consideration of
scientists and that’s why had not been studied eagerly
until last 1-2 decades. Now research on ethylene
