scholarly journals Evolutionary diversification of cytokinin-specific glucosyltransferases in angiosperms and enigma of missing cis-zeatin O-glucosyltransferase gene in Brassicaceae

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lenka Záveská Drábková ◽  
David Honys ◽  
Václav Motyka

AbstractIn the complex process of homeostasis of phytohormones cytokinins (CKs), O-glucosylation catalyzed by specific O-glucosyltransferases represents one of important mechanisms of their reversible inactivation. The CK O-glucosyltransferases belong to a highly divergent and polyphyletic multigene superfamily of glycosyltransferases, of which subfamily 1 containing UDP-glycosyltransferases (UGTs) is the largest in the plant kingdom. It contains recently discovered O and P subfamilies present in higher plant species but not in Arabidopsis thaliana. The cis-zeatin O-glucosyltransferase (cisZOG) genes belong to the O subfamily encoding a stereo-specific O-glucosylation of cis-zeatin-type CKs. We studied different homologous genes, their domains and motifs, and performed a phylogenetic reconstruction to elucidate the plant evolution of the cisZOG gene. We found that the cisZOG homologs do not form a clear separate clade, indicating that diversification of the cisZOG gene took place after the diversification of the main angiosperm families, probably within genera or closely related groups. We confirmed that the gene(s) from group O is(are) not present in A. thaliana and is(are) also missing in the family Brassicaceae. However, cisZOG or its metabolites are found among Brassicaceae clade, indicating that remaining genes from other groups (UGT73—group D and UGT85—group G) are able, at least in part, to substitute the function of group O lost during evolution. This study is the first detailed evolutionary evaluation of relationships among different plant ZOGs within angiosperms.

2008 ◽  
Vol 50 (2) ◽  
pp. 191-202 ◽  
Author(s):  
José G. García-Cerdán ◽  
Dmitry Sveshnikov ◽  
David Dewez ◽  
Stefan Jansson ◽  
Christiane Funk ◽  
...  

2014 ◽  
Vol 80 (17) ◽  
pp. 5503-5514 ◽  
Author(s):  
Christophe Habib ◽  
Armel Houel ◽  
Aurélie Lunazzi ◽  
Jean-François Bernardet ◽  
Anne Berit Olsen ◽  
...  

ABSTRACTThe genusTenacibaculum, a member of the familyFlavobacteriaceae, is an abundant component of marine bacterial ecosystems that also hosts several fish pathogens, some of which are of serious concern for marine aquaculture. Here, we applied multilocus sequence analysis (MLSA) to 114 representatives of most known species in the genus and of the worldwide diversity of the major fish pathogenTenacibaculum maritimum. Recombination hampers precise phylogenetic reconstruction, but the data indicate intertwined environmental and pathogenic lineages, which suggests that pathogenicity evolved independently in several species. At lower phylogenetic levels recombination is also important, and the speciesT. maritimumconstitutes a cohesive group of isolates. Importantly, the data reveal no trace of long-distance dissemination that could be linked to international fish movements. Instead, the high number of distinct genotypes suggests an endemic distribution of strains. The MLSA scheme and the data described in this study will help in monitoringTenacibaculuminfections in marine aquaculture; we show, for instance, that isolates from tenacibaculosis outbreaks in Norwegian salmon farms are related toT. dicentrarchi, a recently described species.


2017 ◽  
Vol 372 (1730) ◽  
pp. 20160380 ◽  
Author(s):  
Marcel Dann ◽  
Dario Leister

Although some elements of the photosynthetic light reactions might appear to be ideal, the overall efficiency of light conversion to biomass has not been optimized during evolution. Because crop plants are depleted of genetic diversity for photosynthesis, efforts to enhance its efficiency with respect to light conversion to yield must generate new variation. In principle, three sources of natural variation are available: (i) rare diversity within extant higher plant species, (ii) photosynthetic variants from algae, and (iii) reconstruction of no longer extant types of plant photosynthesis. Here, we argue for a novel approach that outsources crop photosynthesis to a cyanobacterium that is amenable to adaptive evolution. This system offers numerous advantages, including a short generation time, virtually unlimited population sizes and high mutation rates, together with a versatile toolbox for genetic manipulation. On such a synthetic bacterial platform, 10 000 years of (crop) plant evolution can be recapitulated within weeks. Limitations of this system arise from its unicellular nature, which cannot reproduce all aspects of crop photosynthesis. But successful establishment of such a bacterial host for crop photosynthesis promises not only to enhance the performance of eukaryotic photosynthesis but will also reveal novel facets of the molecular basis of photosynthetic flexibility. This article is part of the themed issue ‘Enhancing photosynthesis in crop plants: targets for improvement’.


2009 ◽  
Vol 23 (3) ◽  
pp. 780-785 ◽  
Author(s):  
Renata Carmo-Oliveira ◽  
Berta Lange de Morretes

The Vochysiaceae are Neotropical trees and shrubs, common in the savanna areas in Central Brazil (Cerrados). The family has been traditionally divided into two tribes: Erismeae, with three genera, and Vochysieae, with five genera. We investigated the stigmatic surface of six Vochysiaceae species, belonging to four genera of Vochysieae: Vochysia, Salvertia, Callisthene and Qualea. Flowers and buds at different developmental stages were collected. Morphological features were observed on fresh material and stigmatic receptivity was inferred based on esterasic activity. Pistils were fixed and embedded in paraplast and sectioned on a rotary microtome; the sections were stained before histological analysis. Stigmas of open flowers were also observed by scanning electron microscopy. Stigmas of all species were wet and showed esterasic activity at pre-anthesis and anthesis stages. Stigmatic surface was continuous with transmitting tissue of glandular nature. Vochysia and Salvertia stigmatic surfaces were formed by multicelular uniseriate hairs, and species of the remaining genera showed papillate surface. The exudate over mature stigmas in all species flowed without rupture of stigmatic surface and pollen tubes grew down between hairs or papillae. Differences on the stigmatic surface agreed with a phylogenetic reconstruction that separated two clades and indicated that Vochysieae is not monophyletic. Stigmatic features could not be associated with pollination and breeding systems.


2019 ◽  
Author(s):  
Benjamin M. Titus ◽  
Charlotte Benedict ◽  
Robert Laroche ◽  
Luciana C. Gusmão ◽  
Vanessa Van Deusen ◽  
...  

AbstractThe clownfish-sea anemone symbiosis has been a model system for understanding fundamental evolutionary and ecological processes. However, our evolutionary understanding of this symbiosis comes entirely from studies of clownfishes. A holistic understanding of a model mutualism requires systematic, biogeographic, and phylogenetic insight into both partners. Here, we conduct the largest phylogenetic analysis of sea anemones (Order Actiniaria) to date, with a focus on expanding the biogeographic and taxonomic sampling of the 10 nominal clownfish-hosting species. Using a combination of mtDNA and nuDNA loci we test 1) the monophyly of each clownfish-hosting family and genus, 2) the current anemone taxonomy that suggests symbioses with clownfishes evolved multiple times within Actiniaria, and 3) whether, like the clownfishes, there is evidence that host anemones have a Coral Triangle biogeographic origin. Our phylogenetic reconstruction demonstrates widespread poly-and para-phyly at the family and genus level, particularly within the family Stichodactylidae and genus Sticodactyla, and suggests that symbioses with clownfishes evolved minimally three times within sea anemones. We further recover evidence for a Tethyan biogeographic origin for some clades. Our data provide the first evidence that clownfish and some sea anemone hosts have different biogeographic origins, and that there may be cryptic species of host anemones. Finally, our findings reflect the need for a major taxonomic revision of the clownfish-hosting sea anemones.


Author(s):  
Łukasz P. Tarkowski ◽  
Vicky G. Tsirkone ◽  
Evgenii M. Osipov ◽  
Steven Beelen ◽  
Willem Lammens ◽  
...  

The metabolism of sucrose is of crucial importance for life on Earth. In plants, enzymes called invertases split sucrose into glucose and fructose, contributing to the regulation of metabolic fluxes. Invertases differ in their localization and pH optimum. Acidic invertases present in plant cell walls and vacuoles belong to glycoside hydrolase family 32 (GH32) and have an all-β structure. In contrast, neutral invertases are located in the cytosol and organelles such as chloroplasts and mitochondria. These poorly understood enzymes are classified into a separate GH100 family. Recent crystal structures of the closely related neutral invertases InvA and InvB from the cyanobacterium Anabaena revealed a predominantly α-helical fold with unique features compared with other sucrose-metabolizing enzymes. Here, a neutral invertase (AtNIN2) from the model plant Arabidopsis thaliana was heterologously expressed, purified and crystallized. As a result, the first neutral invertase structure from a higher plant has been obtained at 3.4 Å resolution. The hexameric AtNIN2 structure is highly similar to that of InvA, pointing to high evolutionary conservation of neutral invertases.


1983 ◽  
Vol 41 (1) ◽  
pp. 57-68 ◽  
Author(s):  
M. Koornneef ◽  
J. Van Eden ◽  
C. J. Hanhart ◽  
A. M. M. De Jongh

SUMMARYNon-germinating gibberellin (GA) responsive mutants are a powerful tool to study genetic fine structure in higher plants. Nine alleles (EMS-and fast neutron-induced) of the ga-1 locus of Arabidopsis thaliana were tested in a complete half-diallel. No wild type ‘recombinants’ were found in the selfed progeny of 9 homoallelic combinations (in total 3 × 105 plants); in the progenies from the 36 selfed hetero allelics the wild type frequency ranged from zero to 6·6 × 10−4. These frequencies allowed the construction of an internally consistent map for five different sites representing eight alleles. The ninth allele covered three sites and thus behaved like an intragenic deletion. The estimate of the total genetic length of the ga-1 locus was 0·07 cM. The order of the sites was also clearly reflected by the association with proximal outside markers. On the assumption that wild type gametes predominantly arise from reciprocal events, it was shown that a cross-over within the ga-1 locus leads to positive interference in the adjacent region.The results are discussed with respect to the mutagen used, the frequencies found in other plant and Drosophila genes, and the possible occurrence of gene conversion.


2020 ◽  
Vol 21 (15) ◽  
pp. 5371 ◽  
Author(s):  
Patrick Schall ◽  
Lucas Marutschke ◽  
Bernhard Grimm

Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are essential cofactors for enzymes, which catalyze a broad spectrum of vital reactions. This paper intends to compile all potential FAD/FMN-binding proteins encoded by the genome of Arabidopsis thaliana. Several computational approaches were applied to group the entire flavoproteome according to (i) different catalytic reactions in enzyme classes, (ii) the localization in subcellular compartments, (iii) different protein families and subclasses, and (iv) their classification to structural properties. Subsequently, the physiological significance of several of the larger flavoprotein families was highlighted. It is conclusive that plants, such as Arabidopsis thaliana, use many flavoenzymes for plant-specific and pivotal metabolic activities during development and for signal transduction pathways in response to biotic and abiotic stress. Thereby, often two up to several homologous genes are found encoding proteins with high protein similarity. It is proposed that these gene families for flavoproteins reflect presumably their need for differential transcriptional control or the expression of similar proteins with modified flavin-binding properties or catalytic activities.


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