Strigolactones: New plant hormones in action

23 Apr 2018 - By: Cristina Prandi and Hinanit Koltai

Strigolactones: new plant hormones in action

Striga Harro
The parasitic weed Striga hermonthica uses strigolactones exuded by the roots of its host, in this case sorghum, as a cue for host presence. The strigolactones induce germination of the seeds of the parasite, which subsequently attaches to the host with a haustorium and robs its host of assimilates, nutrients and water. Photo: Dr Aad van Ast. 


By Cristina Prandi and Hinanit Koltai

Strigolactones were only recently recognized as an important new class of plant hormone, and are now the subject of intensive research. This is leading to rapid growth in our understanding of their diverse roles, as well as novel agricultural applications. The reviews and research in the latest special issue from Journal of Experimental Botany cover a wide range of aspects, from biosynthesis and specificity to the cascade of events leading to perception and transduction, as well as the importance of strigolactone transport and activity in plant development and plant–microbe interactions. The role of the emerging class of non-canonical strigolactones is also covered.

Strigolactones are a class of small terpene-derived molecules that have drawn the attention of the scientific community during the past decade. Although known for decades as germination inducers for the seeds of parasitic plants, in 2005 Akiyama and colleagues reported on their activity as hyphal branching stimulants for arbuscular mycorrhizal fungi, opening new research into the intricate network of communication signals active in the rhizosphere. In 2008 two papers appeared almost simultaneously in Nature (Gomez-Roldan et al., 2008; Umehara et al., 2008) reporting on their role as plant hormones in shoot branching.

Strigolactones are now known unequivocally to play crucial roles both in adaptive changes in plant architecture as a consequence of environmental stimuli and in plant–rhizosphere interactions. They are also recognized as having great potential for agriculture. Such applications include their use in modifying and/or managing root and shoot architecture; as stimulants to induce seed germination of parasitic weeds, controlling infestation by reducing their seed bank; and as ‘biostimulants’ of plant root colonization by arbuscular mycorrhizal fungi, improving plant nutritional capabilities.

Most of the collaborations which led to the research presented in the special issue were developed inside the COST network (see stream.unito.it: FA1206 Strigolactones: biological roles and applications). The concluding meeting of this COST action was the ‘2nd International Congress on Strigolactones’, held in Turin in 2017.

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Journal of Experimental Botany publishes an exciting mix of research, review and comment on fundamental questions of broad interest in plant science. Regular special issues highlight key areas.

 

Author: Cristina Prandi and Hinanit Koltai
Category: Plant Biology
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Cristina Prandi

Cristina Prandi

Cristina Prandi is at the University of Torino in Italy, where she has carried out research on the synthesis of bioactive phytohormone analogues focusing on structure–activity relationships and design of active derivatives, as well as bioimaging studies developing fluorescent-tagged molecules and the use of plant metabolite analogues for their potential anticancer activity. In other research she is working on the characterization of plant extracts and on the formulation of the active ingredients for a new generation of biostimulant.

Hinanit Koltai

Hinanit Koltai

Hinanit Koltai is at the Volcani Centre in Israel. Her research on strigolactones as plant hormones included identification of the role of these molecules in regulation of root development and response to phosphate deficiency, as well as cellular events associated with strigolactone signalling. She is also working on the implementation of new technologies to crops, including for regulation of plant architecture. In other research she is working on plant secondary metabolites as potential anti-inflammatory and anti-cancer treatments.