Open Access

ARTICLE

Genome-Wide Identification of Tomato (Solanum lycopersicum L.) CKX Gene Family and Expression Analysis in the Callus Tissue under Zeatin Treatment

by Zhengfeng Lai, Dongmei Lian, Shaoping Zhang, Yudong Ju, Bizhen Lin, Yunfa Yao, Songhai Wu, Jianji Hong, Zhou Li^*

Subtropical Agriculture Research Institute, Fujian Academy of Agricultural Sciences, Zhangzhou, 363005, China

* Corresponding Author: Zhou Li. Email:

(This article belongs to the Special Issue: Recent Research Trends in Genetics, Genomics, and Physiology of Crop Plants)

Phyton-International Journal of Experimental Botany 2024, 93(6), 1143-1158. https://doi.org/10.32604/phyton.2024.051207

Received 29 February 2024; Accepted 18 April 2024; Issue published 27 June 2024

Abstract

The cytokinin oxidase/dehydrogenase (CKX) enzyme is essential for controlling the fluctuating levels of endogenous cytokinin (CK) and has a significant impact on different aspects of plant growth and development. Nonetheless, there is limited knowledge about CKX genes in tomato (Solanum lycopersicum L.). Here we performed genome-wide identification and analysis of nine SlCKX family members in tomatoes using bioinformatics tools. The results revealed that nine SlCKX genes were unevenly distributed on five chromosomes (Chr.1, Chr.4, Chr.8, Chr.10, and Chr.12). The amino acid length, isoelectric points, and molecular weight of the nine SlCKX proteins ranged from 453 to 553, 5.77 to 8.59, and 51.661 to 62.494 kD, respectively. Subcellular localization analysis indicated that SlCKX2 proteins were located in both the vacuole and cytoplasmic matrix; SlCKX3 and SlCKX5 proteins were located in the vacuole; and SlCKX1, 4, 6, 7, 8, and 9 proteins were located in the cytoplasmic matrix. Furthermore, we observed differences in the gene structures and phylogenetic relationships of SlCKX proteins among different members. SlCKX1-9 were positioned on two out of the three branches of the CKX phylogenetic tree in the multispecies phylogenetic tree construction, revealing their strong conservation within phylogenetic subgroups. Unique patterns of expression of CKX genes were noticed in callus cultures exposed to varying concentrations of exogenous ZT, suggesting their roles in specific developmental and physiological functions in the regeneration system. These results may facilitate subsequent functional analysis of SlCKX genes and provide valuable insights for establishing an efficient regeneration system for tomatoes.

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Keywords

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Supplementary Material

Supplementary Material File

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