An Untranslated cis-Element Regulates the Accumulation of Multiple C₄ Enzymes in Gynandropsis gynandra Mesophyll Cells

Recruitment of pre-existing networks during the evolution of C 4 photosynthesis

“…A similar situation has been found with PPDK and CA genes. Here, cis-regulatory elements located in untranslated regions generate preferential expression in M cells of C 4 G. gynandra [75,76]. Orthologous CA and PPDK genes from C 3 A. thaliana contain the same elements, and although they are silent in terms of cell specificity in C 3 leaves, when placed into C 4 G. gynandra, they lead to expression in the BS.…”

Loss of the Chloroplast Transit Peptide from an Ancestral C3 Carbonic Anhydrase Is Associated with C4 Evolution in the Grass Genus Neurachne

“…Previous studies using the dicot groups Flaveria and Cleomaceae, which also contain closely related C 3 , C 3 -C 4 , and C 4 species, have shown that the C 4 -associated CAs in these taxa likely resulted from the cooption of different ancestral C 3 CA orthologs (Tetu et al, 2007;Tanz et al, 2009;Bräutigam et al, 2011;Kajala et al, 2012;Williams et al, 2016). In Gynandropsis gynandra, bCA4 (GgbCA4) transcripts show preferential accumulation in the MC of this C 4 species (Kajala et al, 2012).…”

“…Some of the processes enabling C 4 evolution appear to be shared between different lineages Ludwig, 2013), including parallel changes to amino acid sequences (Svensson et al, 2003;Christin et al, 2007Christin et al, , 2008Besnard et al, 2009;Kapralov et al, 2011), common changes to cellspecific expression patterns and regulatory factors John et al, 2014;Williams et al, 2016), and even convergent recruitment of specific gene lineages to the C 4 pathway (Christin et al, 2013(Christin et al, , 2014(Christin et al, , 2015John et al, 2014). The instances of commonality and bias in different C 4 lineages are not surprising, as environmental, anatomical, and metabolic constraints, as well as genome content and structure, limit routes of evolutionary innovation (Weinreich et al, 2006;Christin et al, 2010;Edwards and Donoghue, 2013;Stern, 2013, Storz, 2016.…”

“…In contrast, in C 3 plants, most CA activity localizes to the chloroplasts of MC (Everson and Slack, 1968;Poincelot, 1972), and interestingly, a direct role for b-CAs in C 3 photosynthesis does not appear likely; adult plants containing only 10% to 20% of wild-type CA activity show no significant impairment of CO 2 assimilation (Majeau et al, 1994;Price et al, 1994;Williams et al, 1996;Ferreira et al, 2008). Work using species within Flaveria and Cleomaceae has indicated that different mechanisms were used during the evolution of the C 4 -associated b-CA in these two dicot groups (Tetu et al, 2007;Tanz et al, 2009;Kajala et al, 2012;Williams et al, 2016); however, to date, the molecular evolution of b-CA functioning in C 4 photosynthesis has not been examined in any monocot taxon.…”

Understanding metabolite transport and metabolism in C4 plants through RNA-seq

“…The module requires the action of pyrophosphorylase (PPase) and AMP kinase (AMK) to drive the reaction and funnel PP and AMP back into metabolism as phosphate and ADP [23]. The module is only 80% specific to the mesophyll in Zea mays [24 ] and Sorghum bicolor [25] based on transcript abundances (Table 1, data extracted from [24 ]), but also controlled at the posttranscriptional level [26]. Two prototypes of the module are currently known (Figure 1b and c).…”