Affiliation:
1. Department of Botany University of Innsbruck Sternwartestraße 15 6020 Innsbruck Austria
2. Department of Life Sciences University of Trieste Via L. Giorgieri 10 34127 Trieste Italy
3. Institute of Biology University of Graz Holteigasse 6 8010 Graz Austria
Abstract
SummaryExposing their vegetative bodies to the light, lichens are outstanding amongst other fungal symbioses. Not requiring a pre‐established host, ‘lichenized fungi’ build an entirely new structure together with microbial photosynthetic partners that neither can form alone. The signals involved in the transition of a fungus and a compatible photosynthetic partner from a free‐living to a symbiotic state culminating in thallus formation, termed ‘lichenization’, and in the maintenance of the symbiosis, are poorly understood. Here, we synthesise the puzzle pieces of the scarce knowledge available into an updated concept of signalling involved in lichenization, comprising five main stages: (1) the ‘pre‐contact stage’, (2) the ‘contact stage’, (3) ‘envelopment’ of algal cells by the fungus, (4) their ‘incorporation’ into a pre‐thallus and (5) ‘differentiation’ into a complex thallus. Considering the involvement of extracellularly released metabolites in each phase, we propose that compounds such as fungal lectins and algal cyclic peptides elicit early contact between the symbionts‐to‐be, whereas phytohormone signalling, antioxidant protection and carbon exchange through sugars and sugar alcohols are of continued importance throughout all stages. In the fully formed lichen thallus, secondary lichen metabolites and mineral nutrition are suggested to stabilize the functionalities of the thallus, including the associated microbiota.
Cited by
9 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献