Comparative Proteomics Reveals that Phosphorylation of β Carbonic Anhydrase 1 Might be Important for Adaptation to Drought Stress in Brassica napus

Abstract

Little is known about the mechanism of drought tolerance in rapeseed (Brassica napus L.). In this study, different morphological and physiological responses to drought stress were studied in three rapeseed cultivars. For the cultivar 2AF009 with high drought tolerance, comparative proteomic analyses were conducted to determine the molecular mechanism behind. Approximately 138 differentially abundant proteins (DAPs) and 1232 phosphoproteins containing 4469 phosphopeptides were identified. Furthermore, 337 phosphoproteins containing 547 phosphorylation sites demonstrated significant changes. These drought-responsive DAPs and phosphoproteins were mainly involved in signal transduction, photosynthesis, and glutathione-ascorbate metabolism. Notably, 9 DAPs were also identified as drought-responsive phosphoproteins, especially beta carbonic anhydrase 1 (βCA1), which was represented by eight distinct protein spots with different abundant levels during drought stress. Tyr207 phosphorylated site of βCA1 was down-regulated at the phosphorylation level during drought stress, which was also located in the substrate-binding active region of three-dimensional (3D) structure. Moreover, drought stress inhibited CA activity. We concluded that Tyr207 was the most likely phosphorylation target affecting the enzyme activity, and phosphorylation of βCA1 might be important for the response to drought stress in rapeseed. The study provided a new clue for the drought tolerance mechanism in B.napus.

Role of Plant Carbonic Anhydrases under Stress Conditions

“…The hydrogen bonds of the Trp, Arg, and Tyr residues in this site are well organized to recognize the bicarbonate ion such anions as acetate or nitrate are not able to carry out all the necessary interactions with the hydrogen bonds of these amino acid residues. Tyr residues in the active site and bicarbonate binding site structures were recently found to be the key amino acids for the reversible modification by phosphorylation and nitration in response to abiotic and biotic stresses [11,12]. Such modifications allow for blocking the passage of substrate and inhibiting the activity of β-CAs under stress conditions.…”

“…This CA was named β-CA1 by Fabre [5] in the study of CAs of β-family in Arabidopsis leaves. Later, this name started to be used to designate the corresponding stromal CAs in leaves of other plants [12,15]. This enzyme is the second after Rubisco in terms of the amount of protein in the cell (0.5-2% of the total) [106].…”

“…Recent studies show that the CAs are important not only for photosynthesis and for a number of metabolic pathways, including the interconversion of Ci forms, but also they are necessary under certain stress conditions. In this case, changes (fluctuations) in the CA activity can orchestrate the intensity of certain metabolic processes including the rate of photosynthesis [11][12][13].…”

An effective antioxidant defense provides protection against zinc deficiency‐induced oxidative stress in Zn‐efficient maize plants

“…Zn deficiency has also been shown to decrease CO 2 concentration that results from the decreased activity of a Zn-dependent enzyme, carbonic anhydrase (Sharma et al, 1995;Li et al, 2013;Sharma et al, 1994). Studies revealed that carbonic anhydrase is involved in a CO 2 -sensing pathway in guard cells (DiMario et al, 2017) and adaptation to drought stress (Wang et al, 2016).…”

Emerging roles for carbonic anhydrase in mesophyll conductance and photosynthesis

“…The response of g m to increasing temperature was insufficient to keep up with the CO 2 uptake, and CA‐ and/or aquaporin‐facilitated processes were proposed by Bernacchi et al () to underpin the limitation on photosynthesis at higher temperatures. In rapeseed ( Brassica napus L.), βCA1 was downregulated during drought, both at the transcriptional level and by phosphorylation of the substrate‐binding active region (Wang et al , ). Water stress has been further confirmed to have negative impacts on the activities of CA, Rubisco and photosynthesis‐related proteins in other species, including durum wheat ( Triticum durum Desf., Guliyev et al , ), coffee ( Coffea canephora Pierre ex A. Froehner, Marraccini et al , ) and grapevine ( Vitis vinifera L., Król and Weidner, ).…”