Engineering plant architecture via CRISPR/Cas9-mediated alteration of strigolactone biosynthesis

Haroon Butt,Jian You Wang,Magdy Mahfouz,Muhammad Jamil,Salim Al-Babili

doi:10.1186/s12870-018-1387-1

Haroon Butt, Jian You Wang + Show 3 more

Open Access

https://doi.org/10.1186/s12870-018-1387-1

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Abstract

BackgroundPrecision plant genome engineering holds much promise for targeted improvement of crop traits via unprecedented single-base level control over the genetic material. Strigolactones (SLs) are a key determinant of plant architecture, known for their role in inhibiting shoot branching (tillering).ResultsWe used CRISPR/Cas9 in rice (Oryza sativa) for targeted disruption of CAROTENOID CLEAVAGE DIOXYGENASE 7 (CCD7), which controls a key step in SL biosynthesis. The ccd7 mutants exhibited a striking increase in tillering, combined with a reduced height, which could be rescued by application of the synthetic SL analog GR24. Striga germination assays and liquid chromatography–mass spectrometry analysis showed that root exudates of ccd7 mutants were also SL deficient.ConclusionsTaken together, our results show the potential and feasibility of the use of the CRISPR/Cas9 system for targeted engineering of plant architecture and for elucidating the molecular underpinnings of architecture-related traits.

Highlights

Precision plant genome engineering holds much promise for targeted improvement of crop traits via unprecedented single-base level control over the genetic material
We report the engineering of SL biosynthesis by clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated mutation of OsCCD7
The OsCCD7 gene (LOC_Os04g46470) has 7 exons encoding a protein of 609 amino acids (Fig. 1b), which mediates a key step in SL biosynthesis (Fig. 1a)

Summary

Introduction

Precision plant genome engineering holds much promise for targeted improvement of crop traits via unprecedented single-base level control over the genetic material. Strigolactones (SLs) are a key determinant of plant architecture, known for their role in inhibiting shoot branching (tillering). Genome engineering requires molecular scissors capable of making precise double strand breaks (DSBs) in the genome [41, 49]. Strigolactones are a novel class of plant hormones that play an essential role in establishing plant architecture, determining the number of shoot branches/tillers and regulating the growth of primary and lateral roots [3, 21, 28, 48, 50]. Plant roots release SLs into the rhizosphere to trigger hyphal branching in

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