Molecular evolution of two consecutive carotenoid cleavage dioxygenase genes in strigolactone biosynthesis in plants

Abstract

ABSTRACT. Strigolactones are newly discovered plant hormones that perform various functions, from signaling in symbiotic interactions with arbuscular mycorrhizal fungi to controlling outgrowth of axillary buds. We examined the phylogenetic relationships of two carotenoid cleavage dioxygenase genes (CCD7 and CCD8) that are involved in consecutive upstream steps of the proposed strigolactone biosynthesis pathway. The CCD7 and CCD8 sequences from 11 model species, divided into two clades, correspond to sequences from monocotyledons and dicotyledons. However, the sequences from the primitive moss, Physcomitrella patens, appeared to be evolutionarily distinct from those of the angiosperms. CCD7 and CCD8 are much conserved, since no significant positive selection was detected among these plants. Ks values indicated that CCD7 and CCD8 diverged about 290 to 430 million years ago. As essential genes in the strigolactone pathway, the divergence timing of the conserved CCD7 and CCD8 genes reflects the approximate time of generation of strigolactone as a regulatory substance. This timing calculation also coincides with initiation of symbiosis between plants and microorganisms, inferred from ©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 10 (4): 3664-3673 (2011) CCD gene evolution in plants 3665the fossil record. Molecular evolution analyses of genes in metabolic pathways can provide insight concerning gene evolution.

Impacts of strigolactone on shoot branching under phosphate starvation in chrysanthemum (Dendranthema grandiflorum cv. Jinba)

“…The results from the current study showed that at least two DgCCD7 cDNAs exist in chrysanthemum. In all CCDs, exon/intron organization is conserved and the number of exons in CCD7 ranges from 6 to 9 in dicotyledon species (Wang et al, 2011 ). As we only isolated one clone from genomic DNA, the reason for the missing exon in DgCCD7b may due to alternative splicing (Wang et al, 2011 ).…”

“…In all CCDs, exon/intron organization is conserved and the number of exons in CCD7 ranges from 6 to 9 in dicotyledon species (Wang et al, 2011 ). As we only isolated one clone from genomic DNA, the reason for the missing exon in DgCCD7b may due to alternative splicing (Wang et al, 2011 ). With functional complementation of max3-9 mutants, subcellular localization in the plastid stroma and β-carotene cleavage of DgCCD7a supported a conserved function.…”

In Silico Analysis of the Genes Encoding Proteins that Are Involved in the Biosynthesis of the RMS/MAX/D Pathway Revealed New Roles of Strigolactones in Plants

“…The first one, CCD7, is a stereo-specific dioxygenase that cleaves to only 9- cis -β-carotene to produce 9- cis -β-apo-10'-carotenal, which is subsequently cleaved by CCD8 to produce carlactone ( Figure 1 a). Genes that encode both CCDs have been identified in many different plant species, including primitive moss [ 32 , 33 ]. Analyses of Arabidopsis and rice plants that have mutations in the genes that encode CCD7 ( MAX3 —At2g42620; D17 / HTD1 —Os04g0550600) and CCD8 ( MAX4 —At4g32810— D10 , Os01g0746400) revealed a highly-branched phenotype, which is characteristic for strigolactone mutants that was reversible after treatment with a strigolactone analogue [ 5 , 34 , 35 , 36 , 37 ] ( Figure 1 b).…”

Biochemistry and Molecular Biology of Carotenoid Biosynthesis in Chili Peppers (Capsicum spp.)

“…Additionally, carotenoids have a paramount ecological function because they act as attractants for pollinators and seed dispersal agents [13]. Furthermore, oxidative cleavage of carotenoids by a family of carotenoid cleavage dioxygenases (CCDs; enzymes that cleave double bonds) leads to the production of apocarotenoids, compounds with a variety of biological important activities such as phytohormones (ABA, and strigolactones, a group of terpene lactones with hormone activity that promote germination of root parasitic plants, stimulate symbiotic interactions between plants and arbuscular mycorrhizal fungi, and inhibit shoot axillary branching), the visual and signaling molecules retinal (chromophore of various visual pigments in animals) and retinoic acid (nuclear receptor ligand that is a major signal controlling a wide range of transcriptional processes), and the aromatic volatiles β-ionone (pollinator attractant and fruit or vegetable flavor), β-cyclocitral, geranial, geranyl acetone, theaspirone, α-damascenone and β-damascenone responsible for the flavor and aroma/scent of a number of flowers and a diversity of foods [14–16]. …”