Increased expression of mitochondria-localized carbonic anhydrase activity resulted in an increased biomass accumulation in Arabidopsis thaliana

Abstract

Carbonic anhydrase (CA; EC 4.2.1.1) catalyzes the interconversion of CO 2 and HCO 3 − and plays an important role in photosynthetic carbon assimilation. We report that the effect of manipulating AtβCA6 expression on the growth and biomass accumulation of Arabidopsis thaliana shows that AtβCA6 was expressed in mitochondria. Overexpression of AtβCA6 increased the fresh weight, dry weight and rosette leaf area and it was also linked to a slight decrease in the rate of respiration. By contrast, when the respiration rate in the AtβCA6 knock-out mutant SALK_065611 increased, the fresh weight, dry weight and rosette leaf area decreased. The expression level of AtβCA6 mainly affected the expression of the genes that were related to metabolism, photosynthesis and respiration. We discuss these data with respect to a potential role of AtβCA6 in refixation of CO 2 released from respiration and its potential as an option to increase biomass production.

The Cytoplasmic Carbonic Anhydrases βCA2 and βCA4 Are Required for Optimal Plant Growth at Low CO2

“…In addition, Hu et al (2010) presented evidence showing high expression of bCA2 and bCA4 in mesophyll cells, whereas bCA3 had very low expression in mesophyll cells, while Wang et al (2014) reported very low bCA3 expression in leaves with promoter::GUS studies. Since the other CAs that show significant expression are either in the chloroplast (Fett and Coleman, 1994;Villarejo et al, 2005;Fabre et al, 2007;Burén et al, 2011;Hu et al, 2015) or mitochondria (Fabre et al, 2007;Jiang et al, 2014), we conclude that bCA2 and bCA4 are the most abundant CA isoforms in the cytoplasm. This contention is supported by leaf RNAseq data (Table I), GUS staining (Fig.…”

“…More recently, Jiang et al (2014) reported that plants lacking the mitochondrial bCA6 grew slowly on low CO 2 . There have been few studies of other CA isoforms.…”

“…bCA1 and bCA5 have been localized to the chloroplast (Fabre et al, 2007;Hu et al, 2015), while bCA2 and bCA3 are found in the cytosol (Fabre et al, 2007). The two other bCAs, bCA4 and bCA6, have been reported to be localized to the plasma membrane (Fabre et al, 2007;Hu et al, 2010Hu et al, , 2015 and the mitochondria (Fabre et al, 2007;Jiang et al, 2014), respectively.…”

Biomass Production of Three Biofuel Energy Plants’ Use of a New Carbon Resource by Carbonic Anhydrase in Simulated Karst Soils: Mechanism and Capacity

“…They found that the expression of mitochondria-localized CA increased when the respiration rate of leaves decreased. Moreover, with an increase in the expression of CA activity, shoot biomass accumulated in Arabidopsis thaliana [18]. In our previous report [19], we found that microalgae promote the dissolution of limestone.…”

“…Using a method based on stable carbon isotopes, we quantified the proportion of bicarbonate use by plants [11]. Although the conversion to biomass from bicarbonate by the activity of CA has been proposed in studies of plant biomass production for energy [17,18,20], the mechanism and the capacity for bicarbonate use in plants in karst habitats are not fully understood. In this study, we hypothesized that CA activity of plants increased under drought stress, which produced H 2 O and CO 2 from the bicarbonate (HCO 3 − ) in limestone dissolution of karst soils for use in photosynthesis and biomass production.…”