Feedback-Regulation of Strigolactone Biosynthetic Genes and Strigolactone-Regulated Genes in Arabidopsis

Abstract

Strigolactones (SLs) have recently been found to regulate shoot branching, but the functions of SLs at other stages of development and the regulation of SL-related gene expression are mostly unknown in Arabidopsis. In this study, we performed real-time reverse transcription-PCR (RT-PCR) and microarray analysis using wild-type plants and SL-deficient/insensitive mutants to understand the molecular mechanisms underlying SL biosynthesis and signaling. We found that there is responsiveness to SL in the gene expression of Arabidopsis seedlings, which includes feedback regulation of two carotenoid cleavage dioxygenase genes. Microarray analysis revealed that exogenously applied SL regulated the expression of several genes, including light signaling-related genes and auxin-inducible genes. We also found that MORE AXILLARY GROWTH (MAX)2 plays an important role in the expression of SL-regulated genes. Our data support previous studies indicating that SL might function at the seedling stage. Analysis of SL-responsive and MAX2 downstream gene candidates provides new opportunities to broaden our understanding of SL signaling.

Diverse Roles of Strigolactone Signaling in Maize Architecture and the Uncoupling of a Branching-Specific Subnetwork

“…4D). The overall mechanism for feedback regulation of SL biosynthesis is evidently conserved in diverse species (Foo et al, 2005;Snowden et al, 2005;Arite et al, 2007;Mashiguchi et al, 2009;Minakuchi et al, 2010).…”

Strigolactones as mediators of plant growth responses to environmental conditions

“…Mashiguchi and co-workers found that light-signaling-related genes are induced in Arabidopsis seedlings shortly (90 min) following exposure to GR24. 48 Analysis of roots and shoots of WT tomato plants and of the SLs-deficient tomato mutant Sl-ORT1 49,50 suggested that SLs are positive regulators of plant light harvesting. This was deduced from the list of genes induced by GR24, following 24 to 48 h of GR24 treatment, which was enriched in genes putatively associated with light harvesting.…”

Climbing the Branches of the Strigolactones Pathway One Discovery at a Time

“…In Arabidopsis, one transcription factor, BRANCHED1 (BRC1), has been linked to the strigolactone pathway. BRC1 is down-regulated in max mutants buds and upregulated in response to application of strigolactone (Aguilar-Martínez et al, 2007;Mashiguchi et al, 2009). As with the genes in the upstream part of the pathway, the challenge lies in identification of the functions of all these genes.…”