4.3.3 C. japonica seem to have a greater capacity for oxidative stress
We detected the remarkable expansion or positive selection of HSPgenes (including HSP70 and HSP90 ), which probably encode prototypical chaperonin to prevent the accumulation of unfolding proteins and/or assist in the refolding or degradation of denatured proteins (Haslbeck et al., 2005; Beck et al., 2009). The ZNF gene family was also enriched in the C. japonica genome. Zinc finger proteins are the most abundant protein in eukaryotes and have a wide range of structures and functions (Laity et al., 2011). Interestingly, the positive selection or expansion of RING-type zinc finger proteins occurred in C. japonica . As a zinc finger protein widely found in plants and animals, RING-type zinc finger protein confers a strong drought tolerance in Arabidopsis thaliana (Moon et al., 2010), because RING-type zinc finger protein can regulate the ubiquitin–proteasome system to degrade misfolded proteins and thus improve the defense of an organism against external environmental stress (Ryota et al., 2002).
In conclusion, C. japonica ’s metabolism, oxygen supply, and antioxidative stress abilities may help this species to survive longer in drought environments. Due to the high desiccation-tolerance capability of C. japonica , this information will be valuable in the transportation and farming strategies.