get3b mutation affects CO2 assimilation
The proteomic analysis also suggested that components of the dark
reaction were affected by the get3b mutation. Interestingly, not
only three of four paralogous genes of the nuclear encoded small
subunits but also the plastom encoded large subunit of RuBisCo were
affected by the reduction or absence of GET3B. Additionally, RuBisCo
assembly factors like RbcX, CPN60A1, CPN60B1 and CPN10-2 were
significantly affected in get3b (Supplemental table S1). In
total, these constitute six out of nine components necessary to
synthesize RuBisCo in vitro (Aigner et al., 2017). In order to
address this matter, we analyzed the CO2 assimilation ofA. thaliana seedlings by Infra-red gas analyzer (IRGA; Toro et
al., 2019). The measurements revealed that get3b assimilated
significantly less CO2 (Figure 3). During the
measurements we included a complementation line that was previously used
(Xing et al., 2017). The complementation line was able to rescue theget3b assimilation phenotype and restore the levels above those
of the wild-type (Figure 3).
This and the previous data support the results of the proteomic
analysis, that GET3B is required for an efficient light as well as dark
reaction of photosynthesis.