Short-Chain Chitin Oligomers: Promoters of Plant Growth
Alexander J. Winkler,
Jose Alfonso Dominguez-Nuñez,
Inmaculada Aranaz,
César Poza-Carrión,
Katrina Ramonell,
Shauna Somerville,
Marta Berrocal-Lobo
Affiliations
Alexander J. Winkler
Department of Systems and Natural Resources, MONTES (School of Forest Engineering and Natural Environment), Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
Jose Alfonso Dominguez-Nuñez
Department of Systems and Natural Resources, MONTES (School of Forest Engineering and Natural Environment), Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
Inmaculada Aranaz
Departamento de Físico-Química, Instituto de Estudios Bifuncionales, Facultad de Farmacia, Universidad Complutense, Paseo Juan XXIII, 1, 28040 Madrid, Spain
César Poza-Carrión
Centro Nacional de Biotecnología, Calle Darwin, 3, 28049 Madrid, Spain
Katrina Ramonell
Department of Biological Sciences, P.O. Box 870344, University of Alabama, Tuscaloosa, AL 35487, USA
Shauna Somerville
Plant Biology, Carnegie Institution of Science, 260 Panama St., Stanford, CA 94305, USA
Marta Berrocal-Lobo
Department of Systems and Natural Resources, MONTES (School of Forest Engineering and Natural Environment), Universidad Politécnica de Madrid, Ciudad Universitaria s/n, 28040 Madrid, Spain
Chitin is the second most abundant biopolymer in nature after cellulose, and it forms an integral part of insect exoskeletons, crustacean shells, krill and the cell walls of fungal spores, where it is present as a high-molecular-weight molecule. In this study, we showed that a chitin oligosaccharide of lower molecular weight (tetramer) induced genes in Arabidopsis that are principally related to vegetative growth, development and carbon and nitrogen metabolism. Based on plant responses to this chitin tetramer, a low-molecular-weight chitin mix (CHL) enriched to 92% with dimers (2mer), trimers (3mer) and tetramers (4mer) was produced for potential use in biotechnological processes. Compared with untreated plants, CHL-treated plants had increased in vitro fresh weight (10%), radicle length (25%) and total carbon and nitrogen content (6% and 8%, respectively). Our data show that low-molecular-weight forms of chitin might play a role in nature as bio-stimulators of plant growth, and they are also a known direct source of carbon and nitrogen for soil biomass. The biochemical properties of the CHL mix might make it useful as a non-contaminating bio-stimulant of plant growth and a soil restorer for greenhouses and fields.
