The role of mycorrhizas in plant nutrition: field and mutant based approaches

Abstract

The majority of plants, including most crops, form arbuscular mycorrhizas (AM). These associations play an important role in the growth and nutrition of plants. Here we present results from our ongoing research on the role of AM in sustainable production systems. Firstly, we present results of a survey of the formation of AM by field grown tomato plants from across the south-eastern Australian processing tomato industry. This survey revealed low levels of colonisation, which could be explained by various farm management and edaphic factors. Secondly, to explore the role of AM in these farming systems, we grew a mycorrhiza defective tomato mutant and its mycorrhizal wild type progenitor in in-tact cores containing tomato farm soils. This novel genotypic approach to controlling for AM colonization allows us to study the formation and functioning of AM in field soils without the need to fumigate soils to establish non-mycorrhizal controls. Using this approach we found an important role for AM in the nutrition of tomato plants. Given the role of AM in plant nutrition, and the low levels of colonization in the survey, our ongoing research aims to identify better ways to manage AM in the field.