Arbuscular mycorrhizal fungi increase the proportion of cellulose and hemicellulose in the root stele of vetiver grass

Aims Arabidopsis thaliana is the model plant that is mainly used in studying cellulose and hemicellulose (CH) biosynthesis. Unfortunately, A. thaliana does not associate with mycorrhiza and as a result there are only rare reports on the role of arbuscular mycorrhiza (AM) fungi on CH biosynthesis. This study aims to investigate the effects of AM fungi on changing the CH content in mycorrhizal plant. Methods Three AM fungi, Glomus aggregatum, Rhizophagus intraradices and Funneliformis mosseae, were inoculated to vetiver grass (Chrysopogon zizanioides) and grown for 12 months. Roots were harvested, and the proportions of CH, lignin, lipids and hydrosoluble content were analysed. The corresponding root tensile strength (positively correlated with the proportion of CH) was measured to counter check the CH content. Results Plants inoculated with AM showed a higher proportion of CH (P < 0.05) compared with uninoculated ones. This increase was coupled to a 40-60% enhancement in tensile strength. Potential mechanisms for this phenomenon are discussed. Conclusions This is the first study showing that the proportion of CH and tensile strength of plant root could be significantly affected by AM symbiosis. It is thus desirable that future research on CH biosynthesis uses mycorrhizal-associating plants, such as medic (Medicago truncatula) and rice (Oryza sativa).