26
F. M. Romero et al.
Thus, the first step for novel product development is the exploration and discovery
of new potential candidates as BCAs. Ultimately, the success of biocontrol relies on
how well the search and screening process is done. Although there is not a unique and
correct way to perform it, researchers should always keep in mind the final goal of the
product. For example, looking for microorganisms to control postharvest diseases
requires screening of microbes able to grow and colonize the surface of the fruits
quickly to exclude pathogens.
Another strategy to take into consideration is to conduct the isolation of potential
candidates from the same or similar habitats that they will be used. If the BCAs
were pretended to be used to control tomato diseases under greenhouse cultivation,
it would be recommendable to isolate microbes from tomato plants cultivated under
these conditions, so microorganisms will be better adapted. Moreover, screening
should be performed in a way that mimics the conditions under which the agent will
be used to increase control efficiency. Besides, ideal BCAs should be efficient in a
wide range of environmental conditions. Then, it is important to test potential BCAs
at field conditions during different years and climate conditions, and unless the BCAs
is being intended to be used in a relatively constant environment it is important to
determine to what extent environmental parameters such as temperature, moisture,
and soil type affect biological control efficacy. On the other hand, understanding
the mechanisms involved in the control by the BCAs will also help to develop a
better and more efficient control strategy. For instance, parasitic BCAs will require
the application of large doses of biocontrol microbes to ensure a population high
enough to improve control. However, if the main control mechanism is the induction
of resistance in the host, lower doses will be necessary.
Finally, another important aspect that needs to be considered is the composition
of native microbial communities where the BCAs will be inserted. Also, the modification in the communities’ structure provoked by the application of BCAs must be
analyzed because unwanted effects could be originated. For example, there could be
negative effects if the incorporation of biocontrol agents reduces the number of other
beneficial microbes in the plant-associated communities. Nowadays, the use of nextgeneration sequencing techniques has led to a better understanding of the structure
of plant-associated microbial communities, which will be essential to improve the
design and application of biological control strategies.
Regarding the relationship between nutrient management and biological control,
the available information is scant. Certain reports relate the iron deficiency response
with the induction of ISR mediated by beneficial microorganisms. Also, evidence has
been provided on the uptake and distribution of nitrogen during the plant-endophytepathogen interaction. However, the mechanisms involved in these processes, as
well as the true biological meaning of these responses yet to be explored for their
bioefficacy in a befitting manner.
Acknowledgments This work was supported by grants of Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) (PICT 2014-3718, 2014-3648, 2015-1803). A.G, F.R.R and O.A.R
are members of the Research Career of CONICET. F.M.R is member of the Research Career of
Comisión de Investigaciones Científicas (CIC). A.S.N is a postdoctoral fellow of CONICET.
F. M. Romero et al.
Thus, the first step for novel product development is the exploration and discovery
of new potential candidates as BCAs. Ultimately, the success of biocontrol relies on
how well the search and screening process is done. Although there is not a unique and
correct way to perform it, researchers should always keep in mind the final goal of the
product. For example, looking for microorganisms to control postharvest diseases
requires screening of microbes able to grow and colonize the surface of the fruits
quickly to exclude pathogens.
Another strategy to take into consideration is to conduct the isolation of potential
candidates from the same or similar habitats that they will be used. If the BCAs
were pretended to be used to control tomato diseases under greenhouse cultivation,
it would be recommendable to isolate microbes from tomato plants cultivated under
these conditions, so microorganisms will be better adapted. Moreover, screening
should be performed in a way that mimics the conditions under which the agent will
be used to increase control efficiency. Besides, ideal BCAs should be efficient in a
wide range of environmental conditions. Then, it is important to test potential BCAs
at field conditions during different years and climate conditions, and unless the BCAs
is being intended to be used in a relatively constant environment it is important to
determine to what extent environmental parameters such as temperature, moisture,
and soil type affect biological control efficacy. On the other hand, understanding
the mechanisms involved in the control by the BCAs will also help to develop a
better and more efficient control strategy. For instance, parasitic BCAs will require
the application of large doses of biocontrol microbes to ensure a population high
enough to improve control. However, if the main control mechanism is the induction
of resistance in the host, lower doses will be necessary.
Finally, another important aspect that needs to be considered is the composition
of native microbial communities where the BCAs will be inserted. Also, the modification in the communities’ structure provoked by the application of BCAs must be
analyzed because unwanted effects could be originated. For example, there could be
negative effects if the incorporation of biocontrol agents reduces the number of other
beneficial microbes in the plant-associated communities. Nowadays, the use of nextgeneration sequencing techniques has led to a better understanding of the structure
of plant-associated microbial communities, which will be essential to improve the
design and application of biological control strategies.
Regarding the relationship between nutrient management and biological control,
the available information is scant. Certain reports relate the iron deficiency response
with the induction of ISR mediated by beneficial microorganisms. Also, evidence has
been provided on the uptake and distribution of nitrogen during the plant-endophytepathogen interaction. However, the mechanisms involved in these processes, as
well as the true biological meaning of these responses yet to be explored for their
bioefficacy in a befitting manner.
Acknowledgments This work was supported by grants of Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT) (PICT 2014-3718, 2014-3648, 2015-1803). A.G, F.R.R and O.A.R
are members of the Research Career of CONICET. F.M.R is member of the Research Career of
Comisión de Investigaciones Científicas (CIC). A.S.N is a postdoctoral fellow of CONICET.