The interaction between strigolactones and other plant hormones in the regulation of plant development

Abstract

Plant hormones are small molecules derived from various metabolic pathways and are important regulators of plant development. The most recently discovered phytohormone class comprises the carotenoid-derived strigolactones (SLs). For a long time these compounds were only known to be secreted into the rhizosphere where they act as signaling compounds, but now we know they are also active as endogenous plant hormones and they have been in the spotlight ever since. The initial discovery that SLs are involved in the inhibition of axillary bud outgrowth, initiated a multitude of other studies showing that SLs also play a role in defining root architecture, secondary growth, hypocotyl elongation, and seed germination, mostly in interaction with other hormones. Their coordinated action enables the plant to respond in an appropriate manner to environmental factors such as temperature, shading, day length, and nutrient availability. Here, we will review the current knowledge on the crosstalk between SLs and other plant hormones—such as auxin, cytokinin, abscisic acid (ABA), ethylene (ET), and gibberellins (GA)—during different physiological processes. We will furthermore take a bird's eye view of how this hormonal crosstalk enables plants to respond to their ever changing environments.

Cucumber Mosaic Virusas a carotenoid inhibitor reducingPhelipanche aegyptiacainfection in tobacco plants

“…9 Strigolactones, the major class of germination stimulants, 14 are derived from carotenoids through two subsequent enzymatic cleavage steps performed by the carotenoid cleaving dioxygenases CCD7 and CCD8. [29][30][31][32] To date, the impact of virus-infected host plant on parasitism by Phelipanche has not been reported, therefore our study focused on carotenoid content in CMV-infected tobacco roots and its effect on the development of the parasite.…”

SUPPRESSOR OF APICAL DOMINANCE1 of Sporisorium reilianum changes inflorescence branching at early stages in di- and monocot plants and induces fruit abortion in Arabidopsis thaliana

“…changes in leaf venation and secondary growth of transgenic A. thaliana At_GFP-SAD1. [8][9][10] Since we did not detect these additional phenotypes, we speculate that SAD1 manipulates bud outgrowth by hormone-independent regulatory pathways. Detailed evaluation of At_GFP-SAD1 plant development revealed that expression of GFP-SAD1 induces abortion of siliques at early stages of silique development in A. thaliana (Fig.…”

“…7 Hormones like auxin and strigolactones are main players in control of bud outgrowth. 8 If SAD1 modulated branching by interfering with these hormones, we would expect to observe additional phenotypes, i.e. changes in leaf venation and secondary growth of transgenic A. thaliana At_GFP-SAD1.…”

Molecular cloning and expression analysis of GhLOF genes in upland cotton (Gossypium hirsutum L.)

“…Two developmental stages, the formation of axillary meristems and the subsequent axillary bud outgrowth, are involved in shoot development (Shimizu-Sato and Mori, 2001), and many researches have tried to elucidate the mechanisms of the two stages. It has been demonstrated that three phytohormones, auxin, cytokinin, and strigolactone, participate in the regulation of axillary bud outgrowth, while auxin and strigolactone act as inhibiters and cytokinin acts as a promoter (Cheng et al, 2013). The mechanism underlying axillary meristem initiation is unclear, despite the fact that a set of pathway transcription factors have been identified from branching-deficient mutants, including: 1) the NAC domain protein CUP-SHAPED COTYLEDON3 (CUC3) from Arabidopsis (Vroemen et al, 2003;Hibara et al, 2006); 2) the GRAS domain protein LATERAL SUPPRESSOR (LAS) from Arabidopsis (Greb et al, 2003), and its homolog Ls from tomato (Schumacher et al, 1999), as well as MONOCULM1 (MOC1) from rice (Li et al, 2003); 3) R2R3 MYBs LATERAL ORGAN FUSION1/2 (LOF1/2) (Lee et al, 2009) and REGULATOR OF AXILLARY MERISTEMS (RAX1/2/3) (Keller et al, 2006;Müller et al, 2006) from Arabidopsis, and their respective homologs TRIFOLIATE (Tf) (Naza et al, 2013) and BLIND (Bl) (Schmitz et al, 2002) from tomato; 4) the bHLH protein REGULATOR OF AXILLARY MERISTEM FORMATION (ROX) from Arabidopsis (Yang et al, 2012), and its orthologs LAX PANICLE1 (LAX1) from rice (Komatsu et al, 2001(Komatsu et al, , 2003 and BARREN STALK1 (BA1) from maize (Gallavotti et al, 2004).…”