Genome-Wide Identification of the TCP Transcription Factor Family in Chickpea (Cicer arietinum L.) and Their Transcriptional Responses to Dehydration and Exogenous Abscisic Acid Treatments

Chickpea (Cicer arietinum L.) is regarded as one of the important grain legumes of the Fabaceae family and being consumed in many countries in the world. Water deficit is the most pivotal environmental factor constraining the worldwide productivity of chickpea. The TCP transcription factors can act as integrators of multiple growth and environmental stimuli. However, no information on this gene family in chickpea with regard to their potential roles in drought responses was reported. In this study, 23 CaTCP genes were identified and characterized in the chickpea genome. First, their major features, including chromosomal distribution, gene duplication, protein features, and conserved domains, were examined. Subsequently, phylogenetic analyses were used to study the relationship of the identified CaTCPs. Next, to gain an insight into the functions of the CaTCP genes, we examined their expression profiles in various tissues at different growth and developmental stages. Furthermore, we carried out expression analyses of the CaTCP genes in chickpea plants subjected to dehydration and abscisic acid (ABA) treatments using real-time quantitative PCR to identify dehydration- and/or ABA-responsive candidate genes that may be promising for further in planta analyses for potential applications in genetic engineering to develop improved drought-tolerant chickpea varieties. We found six and eight CaTCP genes up- and down-regulated, respectively, by at least twofold in chickpea leaves and/or roots by dehydration treatment, among which eight CaTCPs were also responsive to ABA in at least one of the examined organs. CaTCP07 was noted to be the most induced gene upon dehydration and ABA treatments. Our study is the first report on the comprehensive analysis of the CaTCP gene family in chickpea, and provides useful information for further functional characterizations of individual CaTCP genes in chickpea.