1.12 Perspectives
1.12.1 Metabolites-Inducer Factors
Metabolism is the sum of all the chemical reactions that occur in an organism.
Primary metabolites such as carbohydrates, proteins, lipids nucleic acids among
others, are the end up molecules of carbon, nitrogen, and energy. These metabolites are required for the proper functions of cells and organisms. In contrast, plants
produce molecules known as secondary metabolites, which once were thought to
be the result of aberrant metabolism and possess no activity (Lewinsohn and
Gijzen 2009). Nowadays, secondary metabolites are not only of commercial and
industrial importance used as colors and scents, but also they are key ingredients in
medicinals and nutraceuticals. It is recognized that they protect plants against
being eaten by herbivores and against infection with microbial pathogens; they
serve as attractants for pollinators and seed dispersing animals. Moreover, they
function as agents of plant–plant competition and plant–microbe symbioses.
Therefore, secondary metabolites are relevant in agriculture for plant defense
purposes but their presence is also desirable in foods.
The difference between primary and secondary metabolites is not always easily
to be made. Primary and secondary metabolites share many of the same intermediates and are derived from the same metabolic pathways. Primary metabolites
are essential in order to fulfill daily nutrient requirements related to satisfy energy,
regulation, and structural activities. Secondary metabolites usually are present in
the plant in relatively low quantities and their production, as it was said before,
may be restricted to particular families, genera, or even species.
Metabolites-inducer factors (MIFs) are conditions or compounds that enhance
the production of primary and/or secondary metabolites in plants. Serrano et al.
(2010) showed that applications of nitrophenolate increased the levels of glucose,
fructose, ascorbic acid, citric acid, as well as total phenolics in sweet pepper. In a
study by Nzanza et al. (2011) where T. harzianum and arbuscular mycorrhizal
fungi (AMF) inoculation were used, it was concluded that these fungi inoculants
have the potential to influence yield and nutrient content of greenhouse tomatoes.
Folate content increased in coriander throughout elicitation (Puthusseri et al.
2012). Wang and Frei (2011) reviewed the impact of abiotic environmental
stresses on crop quality. Here, they report that as a general trend stimulation of
protein and antioxidant concentration or lower starch and lipid concentration
occur, but these outcomes depend on numerous confounding physiological,
environmental, and experimental factors.
The presence of both kinds of metabolites is of core relevance since they are
required for the plant itself but also for their consumers. Consequently, further
knowledge is needed that allows to carefully manipulate plant metabolism. Major
knowledge of the direct and indirect causes that lead to the activation of metabolic
pathways is still needed. It remains to be conclusive about what compounds can be
used as MIFs, MIF’s time of application (at what stage to be used), site of
1 Strategies for Sustainable Plant Food Production
37
1.12.1 Metabolites-Inducer Factors
Metabolism is the sum of all the chemical reactions that occur in an organism.
Primary metabolites such as carbohydrates, proteins, lipids nucleic acids among
others, are the end up molecules of carbon, nitrogen, and energy. These metabolites are required for the proper functions of cells and organisms. In contrast, plants
produce molecules known as secondary metabolites, which once were thought to
be the result of aberrant metabolism and possess no activity (Lewinsohn and
Gijzen 2009). Nowadays, secondary metabolites are not only of commercial and
industrial importance used as colors and scents, but also they are key ingredients in
medicinals and nutraceuticals. It is recognized that they protect plants against
being eaten by herbivores and against infection with microbial pathogens; they
serve as attractants for pollinators and seed dispersing animals. Moreover, they
function as agents of plant–plant competition and plant–microbe symbioses.
Therefore, secondary metabolites are relevant in agriculture for plant defense
purposes but their presence is also desirable in foods.
The difference between primary and secondary metabolites is not always easily
to be made. Primary and secondary metabolites share many of the same intermediates and are derived from the same metabolic pathways. Primary metabolites
are essential in order to fulfill daily nutrient requirements related to satisfy energy,
regulation, and structural activities. Secondary metabolites usually are present in
the plant in relatively low quantities and their production, as it was said before,
may be restricted to particular families, genera, or even species.
Metabolites-inducer factors (MIFs) are conditions or compounds that enhance
the production of primary and/or secondary metabolites in plants. Serrano et al.
(2010) showed that applications of nitrophenolate increased the levels of glucose,
fructose, ascorbic acid, citric acid, as well as total phenolics in sweet pepper. In a
study by Nzanza et al. (2011) where T. harzianum and arbuscular mycorrhizal
fungi (AMF) inoculation were used, it was concluded that these fungi inoculants
have the potential to influence yield and nutrient content of greenhouse tomatoes.
Folate content increased in coriander throughout elicitation (Puthusseri et al.
2012). Wang and Frei (2011) reviewed the impact of abiotic environmental
stresses on crop quality. Here, they report that as a general trend stimulation of
protein and antioxidant concentration or lower starch and lipid concentration
occur, but these outcomes depend on numerous confounding physiological,
environmental, and experimental factors.
The presence of both kinds of metabolites is of core relevance since they are
required for the plant itself but also for their consumers. Consequently, further
knowledge is needed that allows to carefully manipulate plant metabolism. Major
knowledge of the direct and indirect causes that lead to the activation of metabolic
pathways is still needed. It remains to be conclusive about what compounds can be
used as MIFs, MIF’s time of application (at what stage to be used), site of
1 Strategies for Sustainable Plant Food Production
37