Overexpression of MdZAT5, an C2H2-Type Zinc Finger Protein, Regulates Anthocyanin Accumulation and Salt Stress Response in Apple Calli and Arabidopsis

Abstract

Zinc finger proteins are widely involved and play an important role in plant growth and abiotic stress. In this research, <i>MdZAT5</i>, a gene encoding C2H2-type zinc finger protein, was cloned and investigated. The <i>MdZAT5</i> was highly expressed in flower tissues by qRT-PCR analyses and GUS staining. Promoter analysis showed that <i>MdZAT5</i> contained multiple response elements, and the expression levels of <i>MdZAT5</i> were induced by various abiotic stress treatments. Overexpression of <i>MdZAT5</i> in apple calli positively regulated anthocyanin accumulation by activating the expressions of anthocyanin biosynthesis-related genes. Overexpression of <i>MdZAT5</i> in <i>Arabidopsis</i> also enhanced the accumulation of anthocyanin. In addition, <i>MdZAT5</i> increased the sensitivity to salt stress in apple calli. Ectopic expression of <i>MdZAT5</i> in <i>Arabidopsis</i> reduced the expression of salt-stress-related genes (<i>AtNHX1</i> and <i>AtABI1</i>) and improved the sensitivity to salt stress. In conclusion, these results suggest that <i>MdZAT5</i> plays a positive regulatory role in anthocyanin accumulation and negatively regulates salt resistance.