Three Novel Adenylate Cyclase Genes Show Significant Biological Functions in Plant

Adenylate cyclase is the key enzyme solely synthesizing cAMP which participates in cell metabolism regulations and functions as an intracellular second messenger. However, the biological functions of plant ACs have not been elucidated clearly for their poor conservative sequences and low detectable cAMP. We performed a systematic study of plant ACs by using Chinese jujube, whose fruit exhibits the highest cAMP content among plants. Three novel ACs were identified from Chinese jujube, and two types of methods including in vitro and in vivo were used to certificate ZjAC1-3 which can catalyze the conversion of ATP into cAMP. The biological functions of significant accelerations of seed germination, root growth, and flowering were found via overexpression of these AC genes in Arabidopsis, and these functions of ACs were further demonstrated by treating the AC-overexpressing transgenic lines and wild type Arabidopsis with bithionol and dibutyryl-cAMP. At last, transcriptome data revealed that the underlying mechanism of the biological functions of ACs might be regulation of the key genes involved in the circadian rhythm pathway and the hormone signal transduction pathway. This research established a foundation for further investigating plant AC genes and provided strong evidence for cAMP serving as a signaling molecule in plants.

Automated summary

This study systematically investigated plant adenylate cyclases using Chinese jujube, a plant with high cAMP content. Three novel ACs were identified and their functions were confirmed using in vitro and in vivo methods. Overexpression of these AC genes in Arabidopsis resulted in accelerated seed germination, root growth, and flowering. Transcriptome data suggested that the biological functions of ACs may be mediated through the regulation of key genes involved in the circadian rhythm pathway and hormone signal transduction pathway. This research lays the foundation for further studying plant AC genes and provides strong evidence for cAMP serving as a signaling molecule in plants.