Identification and expression analysis of Whirly gene families in Camellia sinensis (L.) O. Kuntze

【Objective】To conduct identification and expression analysis of Whirly gene family members in tea trees,so as to provide reference for further exploration of mechanism of Whirly gene family in tea tree growth and stress response.【Method】Leaves of tea plant cultivars Beicha 36,Longjing 43,and Damianbai were taken as materials. Based on conserved structural characteristics of Whirly gene family,CsWhys gene family members were identified from tea genome.The Whirly gene family was visually analyzed by bioinformatics software,and its tissue specificity and spatio-temporal expression pattern were analyzed.【Result】Two CsWhys genes were identified from Shuchazao tea tree,and they were named CsWhy1(xp_028085682.1)and CsWhy2(xp_028102803.1),respectively. Phylogenetic tree analysis showed that CsWhy1and CsWhy2 proteins clustered with the known Whirly proteins located in chloroplasts and mitochondria,respectively.The promoter regions of CsWhys had abundant cis-acting elements such as hormone,stress and MYB transcription factor binding site,and its species were diverse. Tissue specific expression of tea trees showed that CsWhy1 had high expression in leaves and buds,but low expression in stems and roots;CsWhy2 had high expression in different tissues of tea trees.Spatio-temporal expression pattern analysis showed that expression of CsWhys was up-regulated by low temperature,drought,ABA,GA and H₂O₂ at different time points under various abiotic stress treatments. Under cold acclimation,expression pattern of Cswhy1 was opposite in cold-resistant variety Longjing 43 and non-cold-resistant variety Damianbai,while the expression of CsWhy2 was down-regulated in the 2 varieties.【Conclusion】Two CsWhys genes in tea plant genome have typical characteristics of the Whirly family,and the expression of CsWhys have obvious tissue specificity.Therefore,it is speculated that CsWhys gene family plays an important regulatory role in the growth and stress resistance of tea tree buds and leaves.