Variability in Fusarium species Causing Wilt Disease in Crops: A Transcriptomic Approach to Characterize Dialogue Between Host and Pathogen - Crop Improvement: New Approaches and Modern Techniques - page 268

identified association between species (crops and microbes ( Fusarium sp.) can
reveal processes which can be exploited beneficially for applications in biotechnol-
ogy. Specifically, we address the question how the new knowledge gained from
transcriptomic approaches and analyses of interactions between plants and disease
causing microbes ( Fusarium ) can be exploited in ways that will ultimately lead to
crop improvement by development of crop cultivars that are productive under mul-
tiple environmental pressures.
Introduction
The genus Fusarium consists of species that attack almost all food crops. Out of
101 most economically important plants, at least 81 are hosts of Fusarium sp.
(Table 8.1 ) (Nayaka et al. 2011 ). The Fusarium spp are responsible for various
diseases among live-stocks and humans and these diseases are ascribed to myco-
toxins produced by these fungi belong to secondary metabolites (Table 8.2 ). The
diseases caused by Fusarium spp have had several major economic impacts around
the world in time and resulted in loss of billions of dollars. So, due to their economic
importance Fusarium spp are being used as models for various biological and mor-
phological studies. Plant pathogenic fungi show variability as they are known to
contain a considerable number of sub-species/formae specialis or strains, which are
almost morphologically identical but they may have quite different infection capac-
ity on their hosts (Nayaka et al. 2011 ). This variability in pathogenic populations
results in variation in host resistance (Leilani et al. 2006 ). Thus, degree of varia-
tions among plant pathogens are must for understanding the pathogen as well as
the disease they cause. The amount of pathogen variation may have a direct impact
on its biological activity and its role in the environment (Zabalgogeazcoa 2008 ).
The variations may occur at any stage of growth leading to changes in morphology
that determine its host range, inoculum potential, infectivity, and virulence (Parker
and Gregory 2004 ). Therefore, it is relevant to monitor pathogen populations for
shift in virulence with changes in environmental factors and host cultivar(s). Hence,
the variability studies within and between pathogenic populations from different
geographical regions is essential for selection of resistant genotypes in breeding
programs that aim at developing resistant varieties.
Crop Productivity for Food Security
The Environment has a role in limiting the plant productivity due to biotic and abi-
otic stresses, e.g. most or all the existing crops can be significantly affected by dis-
eases and have reduced productivity in terms of yield and quality. The prevention of
diseases by conventional breeding to yield resistant crops is most effective (Akhond
and Machray 2009 ; Gust et al. 2010 ) and is said to be the environmentally friendly