Differential expressions of citrus CAMTAs during fruit development and responses to abiotic stresses

Calmodulin-binding transcription activators (CAMTAs) play important roles in plant growth, developmental processes, and responses to abiotic and biotic factors. Recently, five CAMTA members were identified in Citrus sinensis, however, very little is known about the molecular regulation of these CAMTAs in citrus during fruit development and under abiotic stresses. In this study, the different expression profiles of CsCAMTA genes were found in different tissues and different fruit developmental stages. The CsCAMTA genes also displayed distinct expression patterns after heat, cold, salt, and drought stresses. Furthermore, the expressions of CsCAMTA genes were significantly induced by treatments with salicylic acid, methyl jasmonate, or abscisic acid. The green fluorescent protein gene fused with CsCAMTA was specifically expressed in the nucleus of Nicotiana benthamiana cells. Additionally, CsCAMTA proteins can activate or suppress DNA transcription in yeast. These findings provide helpful information for further studies of stress signals in citrus.