10
Potential Use of Extracts of
Seaweeds Against Plant Pathogens
Jatinder Singh Sangha,
1,2
Robin E. Ross,
3
Sowmyalakshmi Subramanian,
1,4
Alan T. Critchley
5
and Balakrishnan Prithiviraj
1,
*
Introduction
Seaweeds are marine macroalgae, and classified into three phyla based on their pigmentation: Chlorophyta
(green algae), Phaeophyta (brown algae), or Rhodophyta (red algae) (Guiry 2012; Guiry and Guiry
2018). Seaweeds are exploited for numerous uses, as food, in industry, and in agriculture. The use of
seaweeds as an organic amendment in soil has been documented as common practice by farmers in
many parts of the world for many centuries. Some of these whole seaweeds such as kelps (Laminaria
digitata) and rockweed (Ascophyllum nodosum) are still used in agriculture as soil amendments, the
application of extracts in plant protection has been an emerging practice. This is due to the fact that
macroalgae are rich sources of nutrients and also an exceptional source of several biologically active
compounds, including complex polysaccharides, a great variety of secondary metabolites which exhibit
a broad spectrum of bioactivity (Kulik 1995; Lordan et al. 2011). In fact, various algal species have the
potential to be used in innumerable fields such as food, industrial raw materials, therapeutic uses (Gupta
and Abu-Ghannam 2011; Marfaing 2017; Srikong et al. 2017) and agriculture and especially in plant
production as biostimulants (Yakhin et al. 2017).
Seaweeds, in general, are suggested to have inherent bioactive properties due to the presence of various
components and or metabolites, which are produced under normal growth conditions, as well as during
periods when they are challenged by stressors (i.e., desiccation and or pressure of herbivores) (Contreras1
Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, PO Box 550, Truro
B2N 5E3, NS, Canada.
2
Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, 1 Airport, Road, Swift Current,
Saskatchewan, Canada S9H 3X2.
3
Acadian Seaplants Limited, 30 Brown Avenue, Dartmouth, B3B 1X8, NS, Canada.
4
Department of Plant Sciences, 21111, Lakeshore road, Macdonald Campus, McGill University, Montreal, Canada H9X
3V9.
5
Verschuren Centre, Cape Breton University, 1250 Grand Lake Rd, Sydney, Nova Scotia, Canada B1P 6L2.
Emails: jatinder.sangha2@canada.ca; rross@acadian.ca; sowmyalakshmi.subramanian@mail.mcgill.ca;
alan.critchley2016@gmail.com
* Corresponding author: bprithiviraj@dal.ca
Potential Use of Extracts of
Seaweeds Against Plant Pathogens
Jatinder Singh Sangha,
1,2
Robin E. Ross,
3
Sowmyalakshmi Subramanian,
1,4
Alan T. Critchley
5
and Balakrishnan Prithiviraj
1,
*
Introduction
Seaweeds are marine macroalgae, and classified into three phyla based on their pigmentation: Chlorophyta
(green algae), Phaeophyta (brown algae), or Rhodophyta (red algae) (Guiry 2012; Guiry and Guiry
2018). Seaweeds are exploited for numerous uses, as food, in industry, and in agriculture. The use of
seaweeds as an organic amendment in soil has been documented as common practice by farmers in
many parts of the world for many centuries. Some of these whole seaweeds such as kelps (Laminaria
digitata) and rockweed (Ascophyllum nodosum) are still used in agriculture as soil amendments, the
application of extracts in plant protection has been an emerging practice. This is due to the fact that
macroalgae are rich sources of nutrients and also an exceptional source of several biologically active
compounds, including complex polysaccharides, a great variety of secondary metabolites which exhibit
a broad spectrum of bioactivity (Kulik 1995; Lordan et al. 2011). In fact, various algal species have the
potential to be used in innumerable fields such as food, industrial raw materials, therapeutic uses (Gupta
and Abu-Ghannam 2011; Marfaing 2017; Srikong et al. 2017) and agriculture and especially in plant
production as biostimulants (Yakhin et al. 2017).
Seaweeds, in general, are suggested to have inherent bioactive properties due to the presence of various
components and or metabolites, which are produced under normal growth conditions, as well as during
periods when they are challenged by stressors (i.e., desiccation and or pressure of herbivores) (Contreras1
Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, PO Box 550, Truro
B2N 5E3, NS, Canada.
2
Swift Current Research and Development Centre, Agriculture and Agri-Food Canada, 1 Airport, Road, Swift Current,
Saskatchewan, Canada S9H 3X2.
3
Acadian Seaplants Limited, 30 Brown Avenue, Dartmouth, B3B 1X8, NS, Canada.
4
Department of Plant Sciences, 21111, Lakeshore road, Macdonald Campus, McGill University, Montreal, Canada H9X
3V9.
5
Verschuren Centre, Cape Breton University, 1250 Grand Lake Rd, Sydney, Nova Scotia, Canada B1P 6L2.
Emails: jatinder.sangha2@canada.ca; rross@acadian.ca; sowmyalakshmi.subramanian@mail.mcgill.ca;
alan.critchley2016@gmail.com
* Corresponding author: bprithiviraj@dal.ca