Morphological evolution in the graminid clade: comparative floral anatomy of the grass relatives Flagellariaceae and Joinvilleaceae

Sajo, Maria das Graças; Rudall, Paula J.

doi:10.1111/j.1095-8339.2012.01283.x

Cited by 14 publications

(8 citation statements)

References 45 publications

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“…Each branch and each flower is subtended by a small bract, as also shown by Whipple et al (2007), Preston et al (2009), and Sajo and Rudall (2012). Because of difficulty of acquiring appropriate material, we have only limited data.…”

Section: Resultsmentioning

confidence: 58%

Early inflorescence development in the grasses (Poaceae)

Kellogg¹,

Câmara²,

Rudall³

et al. 2013

Front. Plant Sci.

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114

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The shoot apical meristem of grasses produces the primary branches of the inflorescence, controlling inflorescence architecture and hence seed production. Whereas leaves are produced in a distichous pattern, with the primordia separated from each other by an angle of 180°, inflorescence branches are produced in a spiral in most species. The morphology and developmental genetics of the shift in phyllotaxis have been studied extensively in maize and rice. However, in wheat, Brachypodium, and oats, all in the grass subfamily Pooideae, the change in phyllotaxis does not occur; primary inflorescence branches are produced distichously. It is unknown whether the distichous inflorescence originated at the base of Pooideae, or whether it appeared several times independently. In this study, we show that Brachyelytrum, the genus sister to all other Pooideae has spiral phyllotaxis in the inflorescence, but that in the remaining 3000+ species of Pooideae, the phyllotaxis is two-ranked. These two-ranked inflorescences are not perfectly symmetrical, and have a clear “front” and “back;” this developmental axis has never been described in the literature and it is unclear what establishes its polarity. Strictly distichous inflorescences appear somewhat later in the evolution of the subfamily. Two-ranked inflorescences also appear in a few grass outgroups and sporadically elsewhere in the family, but unlike in Pooideae do not generally correlate with a major radiation of species. After production of branches, the inflorescence meristem may be converted to a spikelet meristem or may simply abort; this developmental decision appears to be independent of the branching pattern.

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Section: Resultsmentioning

confidence: 58%

Early inflorescence development in the grasses (Poaceae)

Kellogg¹,

Câmara²,

Rudall³

et al. 2013

Front. Plant Sci.

Self Cite

114

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“…Placement of the rho WGD also elucidates the molecular basis for the evolution of morphological characters. The spikelet serves as a key characteristic of the grasses, though the evolution of the structure has long been a subject of research due to the similarity to closely related graminids ( Rudall and Stuppy 2005 ; Sajo and Rudall 2012 ) and difficulty in determining homology in inflorescence structure between early diverging Poaceae species and the core Poaceae ( Sajo et al 2008 ; Preston et al 2009 ; Sajo and Rudall 2012 ). The influence of the rho WGD event on the development of the spikelet is suggested through analyses of the MADS-box transcription factor gene family AP1 / FUL , which demonstrated that the FUL gene was duplicated prior to the diversification of Poaceae (including Streptochaeta ) but after the divergence of Joinvilleaceae ( Preston and Kellogg 2006 ).…”

Section: Discussionmentioning

confidence: 99%

A phylogenomic assessment of ancient polyploidy and genome evolution across the Poales

et al. 2016

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Comparisons of flowering plant genomes reveal multiple rounds of ancient polyploidy characterized by large intragenomic syntenic blocks. Three such whole-genome duplication (WGD) events, designated as rho (ρ), sigma (σ), and tau (τ), have been identified in the genomes of cereal grasses. Precise dating of these WGD events is necessary to investigate how they have influenced diversification rates, evolutionary innovations, and genomic characteristics such as the GC profile of protein-coding sequences. The timing of these events has remained uncertain due to the paucity of monocot genome sequence data outside the grass family (Poaceae). Phylogenomic analysis of protein-coding genes from sequenced genomes and transcriptome assemblies from 35 species, including representatives of all families within the Poales, has resolved the timing of rho and sigma relative to speciation events and placed tau prior to divergence of Asparagales and the commelinids but after divergence with eudicots. Examination of gene family phylogenies indicates that rho occurred just prior to the diversification of Poaceae and sigma occurred before early diversification of Poales lineages but after the Poales-commelinid split. Additional lineage-specific WGD events were identified on the basis of the transcriptome data. Gene families exhibiting high GC content are underrepresented among those with duplicate genes that persisted following these genome duplications. However, genome duplications had little overall influence on lineage-specific changes in the GC content of coding genes. Improved resolution of the timing of WGD events in monocot history provides evidence for the influence of polyploidization on functional evolution and species diversification.

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“…There are several studies on floral anatomy and development of Poalean families (e.g. Ronse Decraene et al 2002;Sajo et al 2004Sajo et al , 2007Rudall et al 2005;Vrijdaghs et al 2005Vrijdaghs et al , 2009Sokoloff et al 2009;Remizowa et al 2012;Reynders et al 2012;Sajo and Rudall 2012), but for Rapateaceae, there is a lack of ontogenetic information.…”

Section: Introductionmentioning

confidence: 99%

Floral anatomy and development of Saxofridericia aculeata (Rapateaceae) and its taxonomic and phylogenetic significance

Ferrari

Oriani

2016

Plant Syst Evol

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Floral anatomy and development of Saxofridericia aculeata Körn was studied in a comparative approach to contribute to the understanding of the family. Flowers at different developmental stages were analysed with light and scanning electron microscopy, and the nature of the exudate secreted by the floral trichomes was investigated by histochemical tests. The anatomical characteristics observed in S. aculeata flowers were compared with those from other Rapateaceae species by a cluster analysis (UPGMA). The dendrogram generated reflects the groupings that emerged in phylogenetic molecular analyses, highlighting the usefulness of floral anatomy for taxonomy and for the understanding of infrafamilial relationships. The exudate secreted by the trichomes has a polysaccharidic composition. Such trichomes (colleters) occur in the sepals, petals, filaments and around the gynoecium; they are initiated at mid-stage of floral development and are an apomorphy of the family. The flowers are pentacyclic, presenting three initially free sepals, petals, stamens and carpels that mature in a centripetal order. The connate portion of the corolla, which is also adnate to the stamens, has a late development by zonal growth. Gynoecium formation is a combination of postgenital and congenital fusion processes. Data on floral organogenesis of Rapateaceae are first reported here and support the early diverging position of the family in Poales, close to Bromeliaceae.Keywords Cluster analysis Á Colleter Á Monotremoideae Á Postgenital intercarpellary fusion Á Rapateoideae Á

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Morphological evolution in the graminid clade: comparative floral anatomy of the grass relatives Flagellariaceae and Joinvilleaceae

Cited by 14 publications

References 45 publications

Early inflorescence development in the grasses (Poaceae)

Early inflorescence development in the grasses (Poaceae)

A phylogenomic assessment of ancient polyploidy and genome evolution across the Poales

Floral anatomy and development of Saxofridericia aculeata (Rapateaceae) and its taxonomic and phylogenetic significance

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