Could plant biotechnology help breed prebiotic-rich food crops?
Complex carbohydrates that can act as a prebiotic are found in a wide variety of vegetable, root and tuber crops, as well as some fruits and grain crops. However, there is big potential to use biotechnology and genetic techniques to produce new nutritionally-dense crops that have high levels of micronutrients and probiotic carbohydrates, say researchers.
Writing in the Electronic Journal of Biotechnology, the authors’ noted that recent research has shown that is it possible develop nutritionally dense crops to fight widespread malnutrition, especially in the developing world.
“It is encouraging to note that plant breeders are aware that other quality traits such as micronutrients, vitamins and now prebiotics are equally important as are oil and protein,” wrote the team, led by Sangam Dwivedi from New Mexico State University.
Indeed, Dwivedi and colleagues noted that breeders and researchers interested in crop biotechnology are progressively taking a holistic approach “to breed crops that provide wholesome food promoting human health at large.”
“Increasing in the levels of prebiotics together with other quality traits (fat, protein, minerals, and vitamins) in staple food crops is therefore an important strategy to enhance nutrition and health of malnourished people worldwide,” wrote the US-based team.
They said that ‘limited’ research in barley and wheat grains has already revealed good genetic variation for inulin and fructans – adding that while prebiotic compounds are abundant in vegetables, roots, tubers, and fruit, targeted research aimed at identifying genetic variability for prebiotics is yet to begin.
“A multidisciplinary approach involving all stakeholders is needed to develop nutritionally dense and prebiotic-rich cultivars adapted to diverse agro-ecosystems,” they said – noting that transgenic maize, potato and sugarcane have all been bred with high fructan levels, with no adverse effects on plant development, “which suggests that it is feasible to introduce fructan biosynthesis pathways in crops to produce health-imparting prebiotics.”
Dwivedi and colleagues reiterated that while fructooligosaccharides (FOS), inulin, and galactooligosaccharides (GOS) from plants are best-known sources of prebiotics, other potential prebiotics including polysaccharides found in plant cell walls, such as xylans and pectins have also been recognized as the potential sources for diverse polysaccharides to produce new prebiotics.
Indeed, performing a literature search between 2003 and 2014, revealed the presence of prebiotic carbohydrates in a number of food crops, with vegetable and root and tuber crops being the predominant sources, said the team.
They noted that plants identified as containing prebiotic compounds include: garlic, Jerusalem artichoke, leek, okra, dragon fruit, nectarine, chicory, and yacon – while mushroom has also been reported as potential source of prebiotic carbohydrates, said the team.
While there is a wider range of potential plant sources of prebiotics, the team noted that research investigating the genetic variation for prebiotic carbohydrates in most of these crops is in its infancy.
They said that ‘core’ and ‘mini core’ collections that represent diversity of the entire collection of a given species preserved in a genebank are,however, reported in most of the grain crops and could therefore could be used as resource to identify prebiotic-rich germplasm for use in crop breeding.
“Likewise, many genebanks have large germplasm collections of fruits, vegetables, and root and tuber crops, which were previously reported as source of high fructans,” they said. “There is a need to develop representative subsets in these crops, which could be systematically evaluated for prebiotic carbohydrates.”
In addition to identifying the potential genes for prebiotic compounds through genetic databanks, the team also noted that much of the nutritional traits of a crop are highly influenced by environment (location). Indeed they cited evidence from a trial involving 10 lentil cultivars evaluated at two locations for two years, which reported significant year and location effects for sorbitol, mannitol and verbascose, while other studies have detected genotype × environment interactions for inulin content in Jerusalem artichoke.
Source: Electronic Journal of Biotechnology
Volume 17, Issue 5, Pages 238–245, doi: 10.1016/j.ejbt.2014.07.004
“Plant prebiotics and human health: Biotechnology to breed prebiotic-rich nutritious food crops”
Authors: Sangam Dwivedi, et al