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Acta Prataculturae Sinica ›› 2025, Vol. 34 ›› Issue (10): 187-201.DOI: 10.11686/cyxb2024424

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Identification of the chitinase gene family and functional analysis of TrChit3 from white clover

Xiao-fang QIN(), Zhi-rui HE, Tong JIA, Yu-jiao YANG, Wei FU, Hang LI, Yan PENG()   

  1. College of Grassland Science and Technology,Sichuan Agricultural University,Chengdu 611130,China
  • Received:2024-10-28 Revised:2024-12-16 Online:2025-10-20 Published:2025-07-11
  • Contact: Yan PENG

Abstract:

Chitinases are glycoside hydrolases that play an important role in plant growth and development. Relatively few studies have focused on the responses of chitinases to various biotic and abiotic stresses in white clover (Trifolium repens). Therefore, in this study, we searched the whole genome of white clover to identify and characterize its chitinase gene family. A total of 44 chitinase genes were identified in the whole genome of white clover, and they were unevenly distributed on 16 chromosomes. Phylogenetic analysis of these chitinase genes classified them into two mega-groups (GH18 and GH19), with five separate clusters (I-V). Twenty-nine chitinase genes belonged to the GH18 subfamily and 15 belonged to the GH19 subfamily. The genes within the same subfamily genes encoded proteins with similar structures and functions. Promoter analysis showed that the promoter regions of these 44 chitinase genes contained a variety of cis-acting elements related to growth and development, hormones, and stress. Furthermore, quantitative reverse-transcription polymerase chain reaction analyses showed that salt stress and drought stress resulted in significant increases in the transcript levels of chitinase genes, which further verified their roles in the plant stress response. TrChit3 was selected for a detailed analysis of its role in drought resistance. Overexpression of TrChit3 in Arabidopsis thaliana enhanced its resistance to drought stress, as measured by changes in physiological indexes such as relative conductivity and malondialdehyde content. These results lay a foundation for further studies on the roles of chitinases in plants.

Key words: white clover, chitinase, gene family, expression analysis