Genome-wide identification of CNGC genes in Chinese jujube (Ziziphus jujuba Mill.) and ZjCNGC2 mediated signalling cascades in response to cold stress

Abstract

Backgrounds: Cyclic nucleotide gated channels (CNGCs) play multifaceted roles in plant physiological processes, especially with respect to signalling processes, plant development, and responses to environmental stresses. However, little information is known about the CNGC family in the large cosmopolitan family Rhamnaceae, which has strong tolerance to biotic and abiotic stresses. Results: In the current study, a total of 15 ZjCNGCs which located on 7 chromosomes were firstly identified in Chinese jujube (Ziziphus jujuba Mill.), the most important species of Rhamnaceae in terms of economic and ecological values. Phylogenetic analysis showed that these ZjCNGCs could be classified into four groups, ZjCNGC12 belonged to group IVA, and ZjCNGC13, 14, 15 belonged to group IVB. In addition, the paralogous and orthologous homology duplication of ZjCNGC15 occurred during the evolutionary process. The characteristics of ZjCNGCs regarding to exon-intron numbers and post-translational modifications showed diversified structures and functions. Motif composition and protein sequence analysis revealed that the phosphate-binding cassette and hinge regions were conserved among ZjCNGCs. Prediction of the cis-acting regulatory elements and expression profiles by realtime quantitative PCR analysis showed that some of the ZjCNGCs responded to environmental changes, especially ZjCNGC2, which was significantly downregulated in response to cold stress, and ZjCNGC4 was highly induced in response to cold, salt and alkaline stresses. ZjCNGC13 and 14 were highly induced in the phytoplasma-resistant cultivar and downregulated in the susceptible cultivar. Furthermore, ZjCNGC2 could be regulated by cAMP treatment, microtubule changes and interact with ZjMAPKK4, which suggested that cAMP and microtubule might play important roles in ZjCNGC2 mediated ZjMAPKK4 signalling transduction involved in cold stress.

Genome-wide analysis of the bZIP gene family in Chinese jujube (Ziziphus jujuba Mill.)

“…For the cold treatment, calli at same growth stage and condition were transferred at 4 °C and then collected within 0, 1, 6, 12, 24, and 48 h. Calli incubated at 25 °C were collected and used as negative controls [ 26 ]. For the salinity treatment, callus tissues were subjected to a 150 mM NaCl and NaHCO 3 -NaOH solution (pH 9.5) for 0, 1, 6, 12, 24, and 48 h. Samples subjected to sterile water treatment rather than the NaCl and NaHCO 3 -NaOH solution were used as negative controls [ 48 ].…”

The Complex Story of Plant Cyclic Nucleotide-Gated Channels

“…Prior to this, the need for four CNGC subunits to combine to make a channel had been assumed by analogy with animal and bacterial channels, then supported by molecular modelling [ 78 ] (see Section 4 on channel structure). The range of subunit interactions found to date shows that they are not limited to co-members of the five phylogenetic groups within the family (I, II, III, IV-A and IV-B; Figure 1 [ 16 , 17 , 18 , 19 , 21 , 22 , 23 , 79 ]) but can occur across groups. Therefore, CNGC–CNGC interactions are isoform specific but are not restricted to closely related CNGC isoforms.…”

“…CNGC promotors have been found to contain elements associated with responses to abscisic acid, auxin, ethylene, gibberellin, salicylic acid and methyl-jasmonate [ 17 , 18 , 19 , 20 , 21 ], and CNGC transcript levels are highly sensitive to abiotic and biotic stressors [ 17 , 18 , 19 , 20 , 22 , 23 , 79 ]. Notably, it has also been found that Ziziphus jujube CNGC2 expression is rapidly induced by application of cAMP to callus [ 79 ], potentially providing a mechanism for priming signalling pathways involving ZjCNGC2. In silico analysis has also predicted that NtabCNGC expression may be regulated extensively by micro-RNAs and cis -acting regulatory elements [ 18 ].…”

Calcium Mediated Cold Acclimation in Plants: Underlying Signaling and Molecular Mechanisms

“…Additionally, CNGC family has been characterized in Chinese jujube (Ziziphus jujuba Mill.) , and ZjCNGC2 was reported to regulate signaling cascades in response to cold stress ( Wang et al, 2020b ). Further, it was shown that rice CNGC14 and CNGC16 are involved in promoting tolerance toward heat and chilling stresses, and are regulators of Ca 2+ signals in response to temperature stress ( Cui et al, 2020 ).…”