Decoding the CBL gene family in durum wheat: Insights into dual ABA signaling pathways and calcium-mediated drought tolerance.

Calcium signaling is an essential mechanism in plant responses to environmental stressors, facilitated by sensors like the calcineurin B-like (CBL) protein family. This study offers a comprehensive analysis of the CBL gene family in durum wheat (Triticum turgidum ssp. durum), emphasizing their expression patterns in reaction to drought stress and abscisic acid (ABA) treatment. Bioinformatics and gene expression analyses were conducted on the CBL gene family in durum wheat under drought and ABA application. A total of 23 CBL genes (Triticum turgidum CBLs [TtCBLs]) were identified and further grouped into four phylogenetic clusters. Further evolutionary analysis revealed that segmental duplication is the primary driving force in CBL family expansion, and strong purifying selection played a crucial role in their functional integrity. Promoter analysis showed ABA- and stress-responsive cis-elements, suggesting that the gene family has dual regulatory roles in both ABA-dependent and ABA-independent pathways. Expression profiling of TtCBLs demonstrated variable drought and ABA treatment patterns, with notable tissue-specific patterns. TtCBL2 and TtCBL10 emerged as promising candidates contributing to root-specific drought responses. In addition, TtCBL19 emerged as a putative integrator of cross-tolerance mechanisms regulated by both ABA-mediated and non-ABA signaling. This work emphasizes the complex interplay of calcium signaling with ABA-mediated pathways and provides a platform for targeted genetic interventions enhancing drought resilience in cereal crops. Another important point would be to highlight how such findings open up perspectives regarding using in silico approaches to guide active molecular breeding strategies in agriculture.