Gene pyramiding and omics approaches for stress tolerance in leguminous plants - Legumes Under Environmental Stress: Yield, Improvement and Adaptations - page 265

Chapter 16

Gene pyramiding and omics approaches for
stress tolerance in leguminous plants

Neha Handa, Renu Bhardwaj, Ashwani Kumar Thukral, Saroj Arora, Sukhmeen Kaur Kohli, Vandana
Gautam and Tajinder Kaur
Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar, India

16.1 Introduction

enzymatic or structural role during development of
legume seeds (Duranti, 2006). Hence, these are usually
stored in membrane-bound organelles or protein bodies
in parenchyma cells of cotyledons (Duranti, 2006). These
storage proteins are of three types, namely albumins,
globulins and prolamins, of which globulins are most
abundant (Duranti, 2006). Nutritionally, these storage
proteins are rich in the essential amino acid lysine but
deficient in sulphur-rich methionine and cysteine. Hence,
they are usually supplemented with cereals, which are
rich in the latter, along with tubers (Graham & Vance,
2003). Apart from proteins, legumes also form a source of
minerals such as calcium and phosphorus. Carbohydrates,
some water-soluble vitamins and dietary fibre are also
important components of legumes (Liu, 1997).
In addition to providing food security to the world's
population, legumes have also proven beneficial to the
soil in which they are grown (Morel et al., 2012).
According to the US Department of Agriculture (USDA),
these plants have the ability to enhance the organic
matter and porosity thereby improving the structure of
the soil. They also help in decreasing soil pH and recy-
cling nutrients, and they slowly release nitrogen into
the soil thereby enhancing fertility (Morel et al., 2012).
Hence, legumes are either grown in rotation with
cereals or intercropped with them. These beneficial
effects of leguminous plants are mainly due to the ability
of these plants to fix atmospheric nitrogen. These plants
can form symbiotic associations with nitrogen-fixing
bacteria and hence become major contributors to
biological nitrogen fixation - a process of enzymatic
conversion of atmospheric nitrogen to ammonia thereby

The Leguminosae forms the third largest family of
flowering plants after Orchidaceae and Asteraceae and is
known for its great diversity (Doyle & Luckow, 2003).
The family consists of some 670 to 750 genera and 18,000
to 19,000 species, which are usually grouped into three
subfamilies, namely Mimosoideae, Caesalpinoideae and
Papilionoideae, and these are widely distributed in
diverse habitats ranging from forests to deserts, lowlands,
alpine regions and even aquatic habitats of Africa,
America and Asia (Silveira et al., 2010; Olajide et al.,
2013). The plants of this family have wide-ranging
roles - as food crops, ornamentals, forage and green
manure - and these days they are also explored for their
role in herbal medicines (Olajide et al., 2013). Moreover,
members of this family are also economically important
with their roles in paper production, oil production,
wood for fuel and timber, and sources of various chemi-
cals (Lewis et al., 2005). Hence, the family overall has
great significance in providing a livelihood and improving
socioeconomic conditions for many people (Olajide et al.,
2013). Of major significance is that members of this
family are important food crops after cereals, thereby
contributing to food security of the world (Uzoechina,
2009). Legumes are especially rich in proteins and thus
play a vital role in the sustenance of large human popula-
tions of both developing and developed countries.
Amongst all legumes, grain legumes are one of the major
sources of low-cost dietary proteins and minerals (Apata
& Ologhobo, 1997). The high content of proteins is due to
the accumulation of proteins that do not possess any