Identification of the VQ gene family and their responses to abiotic stresses in Litchi chinensis

[ Objective ] VQ proteins are plant-specific proteins with the conserved VQ motifs ( Fxxh- VQxhTG ), which play an important role in plant growth and development as well as in response to abiotic stresses. The role of the VQ gene family in litchi ( Litchi chinensis ) had not been systematically studied. We identified the LcVQ gene family members as well as their expression patterns in different tissues of ly- chee and their responses to abiotic stresses. This laid a foundation for studying its stress-resistant mecha- nism. [ Methods ] The sequences of LcVQ genes were obtained from the L . chinensis genome using bioin- formatics methods , and their physicochemical properties , subcellular localizations , gene structures , and conserved motifs were analyzed ; a phylogenetic tree was constructed using MEGA 6.0 to analyze the phy- logenetic relationships of the VQ proteins in L . chinensis , Arabidopsis , and Oryza sativa ; the responses to various abiotic stresses were verified by the quantitative real-time PCR ( qRT-PCR ) . [ Results ] A total of 18 LcVQ genes were identified from L . chinensis genome , named as LcVQ1 - 18 , which were clustered into 9 subgroups. They were widely distributed on 11 of 15 chromosomes of lychee. The amino acid num- bers of LcVQ proteins were ranged from 111 to 427 , and molecular weights from 12.48 kD to 45.49 kD. Subcellular localizations showed that except for LcVQ15 and LcVQ17 were localized at the cytoplasm , all other LcVQ proteins were localized at the nucleus. The LcVQ promoters contained a large number of growth and development , plant hormone , and stress-responsiveness related response elements. The LcVQ genes expression was varied at different tissues , which was divided into universal expression and specific expression. Under the treatment of low temperature , high temperature , drought , and salt stress , we found that 4 , 3 , 3 , and 4 LcVQ genes were significantly up-regulated at 3 hours of treatment , respective- ly , indicating that these genes could respond to the abiotic stresses. [ Conclusion ] There are 18 VQ mem- bers in the L . chinensis genome with typical VQ binding domains and participate in different stress re- sponses.