Characterization of ABA- and drought-induced class A MebZIPs and their interacting proteins in cassava

Abstract

Background

The class A MebZIP genes have been confirmed to regulate the transcription of ABA-dependent genes carrying the ABRE cis-acting elements, thereby triggering ABA responses or environmental adaptation. However, there has been no research conducted on which class A MebZIP genes regulate cassava drought resistance through the ABA signaling pathway. Therefore, this study explores which class A MebZIP genes may regulate cassava drought resistance via the ABA signaling pathway.

Methods and results

In this research, class A MebZIP and MeSnRK2 genes were re-identified from cassava. Although some changes were found in the gene counts and the number of amino acid residues, the overall changes were not substantial. MebZIP5, -27, -34, and -67 showed consistent high expression across various tissues. Drought induced significant changes in MebZIP27, -34, -49, -67, and -71, particularly in roots. The MeSnRK2 gene family, crucial in ABA signal transduction, exhibited high expression in all tissues. MeSnRK2.1, -2.2, -2.3, -2.7, and -2.9 underwent significant changes in both roots and leaves during drought treatment. Expression analysis under ABA and simulated drought treatments revealed induction of multiple class A MebZIP genes and MeSnRK2 family genes, especially MebZIP67. Two-yeast hybridization and bimolecular fluorescence complementation experimental results suggested that the ABA signal might transmit through SnRK2.1 and subsequently regulate cassava drought resistance via MebZIP67.

Conclusions

In summary, this study provided insights into ABA signal regulation of cassava's drought response through class A MebZIP genes, paving the way for further exploration of their role in cassava drought responses.