SCIENTISTS MAP FUNGAL PARTNERSHIP IN TOMATO ROOT CELLS

Researchers at VIB and Ghent University have created the first detailed cell-by-cell map of how tomato roots respond to colonisation by arbuscular mycorrhizal fungi, according to findings published in Current Biology. The study identified four successive stages of interaction between the plant and fungus Rhizophagus irregularis. Scientists used gene-sequencing technology to analyse activity in nearly 66,000 individual root cells, allowing them to observe molecular changes as the fungal partnership developed.

Arbuscular mycorrhizal fungi form symbioses with the majority of land plants, a relationship that dates back more than 400 million years. The fungi improve plant access to phosphate, nitrogen and other nutrients in exchange for sugars produced by the plant, reducing the need for chemical fertilisers. Previous research had struggled to understand how plants accommodate fungal structures called arbuscules—the main sites of nutrient exchange—inside root cells, because different colonisation stages occur simultaneously in the same root tissue. The team used a fluorescent tag to identify and focus on root regions where the fungus was actively present.

The research identified four distinct stages: root surface cells detecting the arriving fungus, inner cells preparing to allow entry, cells constructing nutrient-exchange structures, and cells housing fully functional fungal structures ready for nutrient trade. Professor Sofie Goormachtig of VIB-UGent Centre for Plant Systems Biology stated the findings reveal molecular programmes underlying the symbiosis and identify genetic regulators that could potentially be used to engineer more efficient, sustainable crops in future.