Role of marine macroalgae in plant protection & improvement for sustainable agriculture technology

Marine macroalgae are plant-like organisms with simple internal structures that generally live in coastal areas. They mainly include different communities of red, brown and green macroalgae. Marine macroalgae commonly occupy intertidal and sublittoral-to-littoral zones on rocks and other hard substrata. They are considered to be an excellent natural biosource in different aspects of agricultural fields. They have great proficiency in improving soil physical and chemical properties. Marine macroalgae are also characterized by producing a large array of biologically active biocidal substances against plant-infecting pathogens. Unfortunately, most available literatures on marine macroalgae and their derivatives mainly focused on their pharmaceutical applications but their potential utilization in sustainable agriculture development is still often regarded as a secondary goal. However, a relatively considerable dataset on marine macroalgae showed that they could play a major role in plant protection and improvement. This review summarizes different aspects of potential macroalgal applications in agriculture. Commercial production and exploitation of specific compounds with interesting biotechnological importance from marine macroalgae including microbicides, nematicides, insecticides, biofertilizers, biostimulators and soil conditioners are highlighted and discussed in detail. Bioactive compounds like fatty acids (in particular polyunsaturated fatty acids (PUFAs), proteins (amino acids), bioflavonoids, sulfated polysaccharides, carotenoids, polyphenols and carbohydrates are considered to have bactericidal, antiviral and fungicidal effects against some plant-infecting pathogens. These biocontrol agents provide multiple benefits and act as useful pointers for improving cultivation practices in diverse habitats. Marine macroalgae can be generally considered as promising multifunctional bioinoculants and ecofriendly environmental tools in recent trends of organic farming.