Genome-wide identification, characterization, and expression analysis of Clavata3 Insensitive receptor Kinases (CIKs) on developmental tissues and under temperature stress conditions in Brassica oleracea

Abstract

Unprecedented climate changes are one of the major global threats to agriculture. Though cauliflower is grown worldwide in different conditions, it is sensitive to temperature fluctuation. Clavata3 Insensitive receptor Kinase (CIK) is one of the important co-receptors involved in WUS-CLV pathway for shoot apical meristem (SAM) maintenance, floral development and environment buffering. In this study we did genome-wide identification and characterization of CIKs in Brassica oleracea var. botrytis cv. Korso. Expression analysis was conducted on developmental tissues and short-term heat and cold stress conditions. Seven fulllength BolCIKs have been identified in the Korso genome through comparison against Arabidopsis thaliana CIKs. Gene structure and motifs are distinct between each sub-class. Ka/Ks ratios showed that all CIKs underwent purifying selection. Abundance of stress-responsive cis-elements, such as MYB and MYC recognition sites, showed the involvement of BolCIK in environmental stress regulation. Among the nine developmental tissues such as leaf, stem, root, curd, sepal, petal, stamen, pistil, and silique, except BolCIK4 and BolCIK5a, CIKs were merely detected in leaves. Contrastingly, expression of all BolCIKs was detected in stem, curd, and reproductive organs. Importantly, most of the BolCIKs were highly expressed in sepal, petal, pistil, and siliques. In SAM specific manner, BolCIK3 and BolCIK6 are upregulated in heat stress and cold stress, respectively. Other BolCIKs expressions are varying between tissues-types and stress conditions. Since CIKs can possibly be involved in thermomorphogenesis, results of this work may lead to further exploration of its function to improve climate resilience in cauliflower.