Analysis and manipulation of strigolactone biosynthesis in petunia

• Forschungsstelle: COST
• Projektnummer: C14.0074
• Projekttitel Englisch: Analysis and manipulation of strigolactone biosynthesis in petunia

Schlüsselwörter (Englisch)

Strigolactone biosynthesis; arbuscular mycorrhiza; petunia; CCD7; CCD8; D27; MAX1; D53

Forschungsprogramme (Englisch)

COST-Action FA1206 - Strigolactones: biological roles and applications

Kurzbeschreibung (Englisch)

Strigolactones (SL) are central regulators of shoot architecture and stimulants of the root symbiosis with arbuscular mycorrhizal (AM) fungi. In addition they have various hormone-like effects in the root, and they act as germination stimulants of parasitic weeds. Since their discovery, major progress has been made in the analysis of SL biosynthesis and sensing, and their various roles in plant development and interactions with the biotic environment. However, further effort is required to use this knowledge for application in crops. We will study the expression of SL biosynthetic genes in response to endogenous and exogenous factors such as hormones and nutrients, respectively. We will develop SL reporter lines in petunia as sensor tools to analyze SL distribution at cellular resolution. Furthermore, we will analyze the potential of overexpression of SL biosynthetic genes to increase SL production in an attempt to manipulate petunia as a model for crop improvement. The research program consists of three interrelated Swiss research projects that are part of the COST Action FA1206. In short, the three individual projects target strigolactone biosynthesis, strigolactone exudation and strigolactone effects on rhizosphere microbiota and are directed by the joint project partners Reinhardt, Borghi/Martinoia and Schlaeppi/vdHeijden, respectively.

Partner und Internationale Organisationen (Englisch)

AT; BE; BG; HR; CZ; DK; FR; DE; EL; HU; IL; IT; NL; NO; PL; PT; RO; RS; SK; SI; ES; SE; UK; JP; AU; US

Abstract (Englisch)

Strigolactone (SL) research has increased markedly since their discovery as a plant hormone in 2008 for their role in inhibiting shoot branching. During the last years, novel hormonal functions have been demonstrated and important progress has been made in deciphering the biosynthesis pathway from carotenoids with the identification of the intermediate carlactone. SLs exuded by the host root stimulate hyphal growth of the obligate bio-trophic arbuscular mycorrhizal (AM) fungi. Arbuscular mycorrhizal symbiosis occurring in more than 80% of land plants, should play in the future a central role in agriculture to reduce abiotic stresses. Later during evolution, the obligate parasitic plants, Striga (witchweeds) and Orobanche (broomrapes), causing devastating yield reductions in several major crops, used SLs to develop a system inducing seed germination only when seeds were in close proximity to the host root. In order to assess SL distribution in plant tissues at high resolution, we have carried out RNAseq experiments after addition of exogenous SL to identify SL-responsive genes, the promoters of which will be used for the construction of reporter lines with GFP and GUS. In addition, we have cloned the promoters of SL biosynthetic genes. These are also used to generate GFP- and GUS-based marker lines in order to identify the site of SL biosynthesis in the plant tissues. Moreover, we measured expression of genes coding for enzymes involved in biosynthesis and signaling of SL under various abiotic conditions to see if these genes are regulated only by SLs or by other factors. Finally, we are using the open reading frames (ORFs) of the SL biosynthetic genes to transform petunia in order to obtain SL-overproducing plants. These will be crossed with lines that overexpress the SL transporter PhPDR1 to generate 'high strigolactone performance' (HSP) lines in Petunia hybrida. The effect of manipulated SL production and secretion will be evaluated by next generation sequencing (NGS) of the microbiome in the rhizosphere with a focus on the diverse bacterial communities and on AM fungi. Our ultimate joint goal is to better understand SL biology and explore the application of this knowledge to crops.

Datenbankreferenzen (Englisch)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C14.0074