Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic Stress
Cytokinin oxidases/dehydrogenases (CKXs) play a crucial role in modulating plant stress resistance by degrading cytokinins. The ‘duli’ pear (<i>Pyrus betulifolia Bunge</i>), a highly stress-resistant cultivar, is widely used as a rootstock in pear cultivation. This study aims to comprehe...
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2025-01-01
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| Series: | Horticulturae |
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| author | Weimin Wang Ting Xie Jiaojiao He Kuozhen Nie Zijuan He Yuxing Zhang Yingli Li |
| author_facet | Weimin Wang Ting Xie Jiaojiao He Kuozhen Nie Zijuan He Yuxing Zhang Yingli Li |
| author_sort | Weimin Wang |
| collection | DOAJ |
| description | Cytokinin oxidases/dehydrogenases (CKXs) play a crucial role in modulating plant stress resistance by degrading cytokinins. The ‘duli’ pear (<i>Pyrus betulifolia Bunge</i>), a highly stress-resistant cultivar, is widely used as a rootstock in pear cultivation. This study aims to comprehensively identify and characterize the <i>PbCKX</i> gene family in ‘duli’. A total of 10 <i>PbCKX</i> genes were identified, which are unevenly distributed across five chromosomes and classified into four groups based on sequence similarity and phylogenetic relationships. The <i>PbCKX</i> genes exhibit a high degree of conservation in motifs and structural features, although exon structure variations are observed. Comparative analysis revealed 10 homologous gene pairs between ‘duli’ and <i>Arabidopsis</i> and 14 pairs between ‘duli’ and apple. Additionally, cis-acting elements related to abiotic stress, hormone responses, and light responsiveness were identified in the promoter regions of the <i>PbCKX</i> genes. RNA-seq analysis showed that <i>PbCKX1</i> and <i>PbCKX2</i> were predominantly expressed in roots, while <i>PbCKX3</i> to <i>PbCKX10</i> had higher expression in leaves. The <i>PbCKX</i> genes responded to both exogenous hormones and salt stress, with salt stress inducing a more pronounced response. Most abiotic stress treatments led to the downregulation of <i>PbCKX4</i> and <i>PbCKX9</i>, while <i>PbCKX6</i> and <i>PbCKX8</i> were upregulated. Notably, treatments with Abscisic acid and NaCl significantly enhanced CKX enzyme activity in ‘duli’ over 20 days, reducing levels of zeatin and isopentenyladenine. Conversely, treatments with gibberellin, cytokinin, and auxin significantly reduced CKX enzyme activity and increased concentrations of zeatin and isopentenyladenine over the same period. These findings provide valuable insights for future studies on the functional role of <i>PbCKX</i> genes in abiotic stress responses in ‘duli’. |
| format | Article |
| id | doaj-art-f88bc149631e4bb8b590c500ebda6916 |
| institution | Kabale University |
| issn | 2311-7524 |
| language | English |
| publishDate | 2025-01-01 |
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| series | Horticulturae |
| spelling | doaj-art-f88bc149631e4bb8b590c500ebda69162025-01-24T13:34:31ZengMDPI AGHorticulturae2311-75242025-01-011112910.3390/horticulturae11010029Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic StressWeimin Wang0Ting Xie1Jiaojiao He2Kuozhen Nie3Zijuan He4Yuxing Zhang5Yingli Li6College of Horticulture, Hebei Agricultural University, Baoding 071001, ChinaCollege of Horticulture, Hebei Agricultural University, Baoding 071001, ChinaCollege of Horticulture, Hebei Agricultural University, Baoding 071001, ChinaCollege of Horticulture, Hebei Agricultural University, Baoding 071001, ChinaCollege of Horticulture, Hebei Agricultural University, Baoding 071001, ChinaCollege of Horticulture, Hebei Agricultural University, Baoding 071001, ChinaCollege of Horticulture, Hebei Agricultural University, Baoding 071001, ChinaCytokinin oxidases/dehydrogenases (CKXs) play a crucial role in modulating plant stress resistance by degrading cytokinins. The ‘duli’ pear (<i>Pyrus betulifolia Bunge</i>), a highly stress-resistant cultivar, is widely used as a rootstock in pear cultivation. This study aims to comprehensively identify and characterize the <i>PbCKX</i> gene family in ‘duli’. A total of 10 <i>PbCKX</i> genes were identified, which are unevenly distributed across five chromosomes and classified into four groups based on sequence similarity and phylogenetic relationships. The <i>PbCKX</i> genes exhibit a high degree of conservation in motifs and structural features, although exon structure variations are observed. Comparative analysis revealed 10 homologous gene pairs between ‘duli’ and <i>Arabidopsis</i> and 14 pairs between ‘duli’ and apple. Additionally, cis-acting elements related to abiotic stress, hormone responses, and light responsiveness were identified in the promoter regions of the <i>PbCKX</i> genes. RNA-seq analysis showed that <i>PbCKX1</i> and <i>PbCKX2</i> were predominantly expressed in roots, while <i>PbCKX3</i> to <i>PbCKX10</i> had higher expression in leaves. The <i>PbCKX</i> genes responded to both exogenous hormones and salt stress, with salt stress inducing a more pronounced response. Most abiotic stress treatments led to the downregulation of <i>PbCKX4</i> and <i>PbCKX9</i>, while <i>PbCKX6</i> and <i>PbCKX8</i> were upregulated. Notably, treatments with Abscisic acid and NaCl significantly enhanced CKX enzyme activity in ‘duli’ over 20 days, reducing levels of zeatin and isopentenyladenine. Conversely, treatments with gibberellin, cytokinin, and auxin significantly reduced CKX enzyme activity and increased concentrations of zeatin and isopentenyladenine over the same period. These findings provide valuable insights for future studies on the functional role of <i>PbCKX</i> genes in abiotic stress responses in ‘duli’.https://www.mdpi.com/2311-7524/11/1/29<i>Pyrus betulifolia Bunge</i>CKX gene familyphytohormoneabiotic stresses |
| spellingShingle | Weimin Wang Ting Xie Jiaojiao He Kuozhen Nie Zijuan He Yuxing Zhang Yingli Li Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic Stress Horticulturae <i>Pyrus betulifolia Bunge</i> CKX gene family phytohormone abiotic stresses |
| title | Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic Stress |
| title_full | Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic Stress |
| title_fullStr | Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic Stress |
| title_full_unstemmed | Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic Stress |
| title_short | Cytokinin Oxidase (CKX) Family Members in ‘duli’ (<i>Pyrus betulifolia Bunge</i>): Genome-Wide Identification and Tissue Expression Profile Under Abiotic Stress |
| title_sort | cytokinin oxidase ckx family members in duli i pyrus betulifolia bunge i genome wide identification and tissue expression profile under abiotic stress |
| topic | <i>Pyrus betulifolia Bunge</i> CKX gene family phytohormone abiotic stresses |
| url | https://www.mdpi.com/2311-7524/11/1/29 |
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