Taxonomy and systematics are key to biological information: Arabidopsis, Eutrema (Thellungiella), Noccaea and Schrenkiella (Brassicaceae) as examples

Abstract

Taxonomy and systematics provide the names and evolutionary framework for any biological study. Without these names there is no access to a biological context of the evolutionary processes which gave rise to a given taxon: close relatives and sister species (hybridization), more distantly related taxa (ancestral states), for example. This is not only true for the single species a research project is focusing on, but also for its relatives, which might be selected for comparative approaches and future research. Nevertheless, taxonomical and systematic knowledge is rarely fully explored and considered across biological disciplines. One would expect the situation to be more developed with model organisms such as Noccaea, Arabidopsis, Schrenkiella and Eutrema (Thellungiella). However, we show the reverse. Using Arabidopsis halleri and Noccaea caerulescens, two model species among metal accumulating taxa, we summarize and reflect past taxonomy and systematics of Arabidopsis and Noccaea and provide a modern synthesis of taxonomic, systematic and evolutionary perspectives. The same is presented for several species of Eutrema s. l. and Schrenkiella recently appeared as models for studying stress tolerance in plants and widely known under the name Thellungiella.

Genome Structure of the Heavy Metal Hyperaccumulator Noccaea caerulescens and Its Stability on Metalliferous and Nonmetalliferous Soils

“…However, the generic treatment of the tribe is far from settled, and up to 12 genera are recognized in Coluteocarpeae by F.K. Meyer (Meyer, 2001(Meyer, , 2006a(Meyer, , 2006bKoch and German, 2013).…”

“…calaminare). As the morphological variation often has a clinal character, the taxonomic and biological value of various intraspecific taxa is questionable, and detailed studies will be needed to resolve this issue (for discussion, see Koch and German, 2013). In addition to pervasive morphological variation (Koch and German, 2013) apparently reinforced by geographical constraints (Besnard et al, 2009), there is also pronounced phenotypic variation in metal tolerance and accumulation (Escarré et al, 2000;Reeves et al, 2001;Assunção et al, 2006;Xing et al, 2008;Krämer, 2010;Tuomainen et al, 2010).…”

A Time-Calibrated Road Map of Brassicaceae Species Radiation and Evolutionary History

“…However, boundaries between related genera were often poorly delimited and attempts to group species diversity into higher order entities often failed in circumscribing monophyletic groups (e.g., for an overview: Arabis [Koch et al, 1999[Koch et al, , 2000[Koch et al, , 2001, Arabidopsis Koch and German, 2013], Lepidium , Thlaspi [Mummenhoff et al, 1997], and family-wide [Al-Shehbaz, 2012]). Therefore, past concepts combining genera into so-called tribes resulted not only in artificial but also contradicting concepts (reviewed in Koch and Al-Shehbaz, 2009;Lysak and Koch, 2011;Al-Shehbaz, 2012).…”

Which changes are needed to render all genera of the German flora monophyletic?

“…, 1997bKoch & Mummenhof 2001). Microthlaspi and Noccaea do not group in tribe Thlaspideae, but are members of tribe Coluteocarpeae (Koch & German 2013 Koch & Bernhardt 2004), has to be included in Microthlaspi as M. perfoliatum (L.) F. K. Mey. It has also been proposed to combine most genera of tribe Coluteocarpeae in a broadly deined Noccaea (Al-Shehbaz 2012).…”