Abstract:In order to explore the characteristics and functions of the chitinase gene family (CHis), eighteen AcCHi genes were identified from Actinidia chinensis. The phylogenetic analysis showed that they clustered in GH18 and GH19 clusters and were divided into 6 groups with high similarity in conserved domain, gene structure and protein structure among the members. The cis-acting elements of AcCHi genes promoter region were mainly involved in hormone response, abiotic stress response and growth and development regulation. The 18 AcCHi genes were unevenly distributed on 12 chromosomes, and 5 of them had fragment duplication. The expression of AcCHis might be regulated by miR172 and miR408. In AcCHis, the transcription of GH18 members and GH19 members in different tissues, such as mature fruit, young fruit, leaf, stem, flower, was significantly different. During the storage of kiwifruit fruit, 90.9% of GH18 members had no or low expression, however, 71.4% of GH19 members showed differential expression. The expression of AcCHi8 in fruits was up-regulated at 25 ℃ for 1 week and at 4 ℃ for 1 to 3 weeks, and the expression of AcCHi8 was the highest at 4 ℃ for 3 weeks (188 times to the control), while the expression of AcCHi8 was down-regulated at 25 ℃ for 1 week after ABA soaking. Therefore, it was suggested that AcCHi genes might be involved in the process of storage and softening of postharvest fruits.