Identification and Functional Analysis of Ca²⁺-ATPase Gene Family in Banana

Ca²⁺-ATPase is a vital Ca²⁺ efflux channel in plants, which plays an important role in maintaining cell homeostasis and inducing plant response to stress. In this study, bioinformatics and molecular biology were used to analyze the members of Ca²⁺-ATPase family in banana A genome, detect the changes of gene expression and verify gene function, so as to provide reference for exploring the mechanism of banana salt tolerance.

BLAST the members of banana A genome in banana genome database by gene family name combined with Arabidopsis and rice Ca²⁺-ATPase sequences, and use Pfam, ExPASy, Cell-PLoc, NCBI, MEGA-X, TBtools and other online websites or software to predict and analyze the protein physicochemical properties, subcellular localization, conservative domain and cis-acting elements of banana Ca²⁺-ATPase. The expression of the family genes was analyzed by qRT-PCR, and the subcellular localization and prokaryotic expression of the key genes were analyzed.

In this study, 20 members of Ca²⁺-ATPase family were identified in banana A genome, including 13 MaACAs and 7 MaECAs; proteins analysis of physicochemical properties showed that Ca²⁺-ATPase contained 6-11 transmembrane structures, encoding amino acids between 857 and 1 103. Subcellular localization predicted that MaACAs might be located on plasma membrane, chloroplast, endoplasmic reticulum and tonoplast, while MaECAs was located in endoplasmic reticulum. The conserved motifs are highly consistent, including four conserved domains peculiar to the family except MaACA13, responses to light, hormone, defense and stress. qRT-PCR results showed that other members of Ca²⁺-ATPase gene family except MaECA3 were up-regulated in Brazilian banana cells treated with 100 mmol·L^-1 NaCl, in which MaACA5 and MaACA10 were up-regulated to a large extent, and the expression of these two genes was affected by Ca²⁺. The results of subcellular localization of tobacco leaves showed that MaACA5 and MaACA10 were located on the plasma membrane, and the recombinant plasmids pET28a-MaACA5, pET28a-MaACA10 and transformed into E. coli BL21 were superior to the control strains under the conditions of 800 mmol·L^-1NaCl, 800 mmol·L^-1 mannitol and 50 ℃.

20 Ca²⁺-ATPase family members were identified in banana A genome, the gene structure was highly conservative, including hormone, defense and stress-related responses, MaACA5 and MaACA10 related to banana salt tolerance were screened and prokaryotic expression to verify the gene function, which provides a reference for further study of banana salt tolerance.