Abstract

The potential use of cell wall derived oligosaccharides as regulators of plant defence, growth and development was already referred to nearly 20 years ago in a first review (Albersheim and Darvill, 1985). These bioactives, called oligosaccharins, are now relatively easy to produce and ready to face public acceptance because of their natural origin. In this review, we summarise the results obtained by a consortium of research institutions and companies working in the preparation, bioactivity studies, and practical use of different oligosaccharides as biostimulants in agriculture. We will start by explaining how fungal cell wall-derived chitosan and chitooligosaccharides stimulate plant defence, growth and improve crop yield and quality of many species. Then we will focus on different oligosaccharides such as oligogalacturonides, prepared from citrus pectin, that can partial or totally substitute phytohormones in the culture “in vitro” of sugar cane, citrus, coffee, tomato, rice and banana plants, reducing the time required for plant propagation, avoiding culture-induced genetic changes and increasing field survival percentage of these plants but also inducing rooting and plant growth. Then we will explain how the use of xyloglucan oligosaccharides, derived from the plant cell wall cannot only promote plant growth but also differentially act on the regulation of diverse biotic and abiotic stress-related genes. We will also discuss several field experiments where the foliar application of lipo-chitooligosaccharides, a nodulation factor in the soybean-rhizobium symbiosis, was shown to be effective in the enhancement of plant growth and production yield in soybean, wheat and corn. In short, this work aims to synthesize and explain the roles of different oligosaccharins and explain why their agricultural use will be likely to increase within the next years.