Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus Ethephon
Thidiazuron (TDZ) is a widely used chemical defoliant in cotton and can stimulate the production of ethylene in leaves, which is believed to be the key factor in inducing leaf abscission. Ethephon (Eth) can also stimulate ethylene production in leaves, but it is less effective in promoting leaf shed...
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MDPI AG
2023-04-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/24/8/7590 |
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| author | Baopeng Liao Fangjun Li Fei Yi Mingwei Du Xiaoli Tian Zhaohu Li |
| author_facet | Baopeng Liao Fangjun Li Fei Yi Mingwei Du Xiaoli Tian Zhaohu Li |
| author_sort | Baopeng Liao |
| collection | DOAJ |
| description | Thidiazuron (TDZ) is a widely used chemical defoliant in cotton and can stimulate the production of ethylene in leaves, which is believed to be the key factor in inducing leaf abscission. Ethephon (Eth) can also stimulate ethylene production in leaves, but it is less effective in promoting leaf shedding. In this study, the enzyme-linked immunosorbent assays (ELISA) and RNA-seq were used to determine specific changes at hormonal levels as well as transcriptomic mechanisms induced by TDZ compared with Eth. The TDZ significantly reduced the levels of auxin and cytokinin in cotton leaves, but no considerable changes were observed for Eth. In addition, TDZ specifically increased the levels of brassinosteroids and jasmonic acid in the leaves. A total of 13 764 differentially expressed genes that specifically responded to TDZ were identified by RNA-seq. The analysis of KEGG functional categories suggested that the synthesis, metabolism, and signal transduction of auxin, cytokinin, and brassinosteroid were all involved in the TDZ-induced abscission of cotton leaves. Eight auxin transport genes (<i>GhPIN1-c_D</i>, <i>GhPIN3_D</i>, <i>GhPIN8_A</i>, <i>GhABCB19-b_A</i>, <i>GhABCB19-b_D</i>, <i>GhABCB2-b_D</i>, <i>GhLAX6_A</i>, and <i>GhLAX7_D</i>) specifically responded to TDZ. The <i>pro35S::GhPIN3a::YFP</i> transgenic plants showed lower defoliation than the wild type treated with TDZ, and YFP fluorescence in leaves was almost extinguished after treatment with TDZ rather than Eth. This provides direct evidence that GhPIN3a is involved in the leaf abscission induced by TDZ. We found that 959 transcription factors (TFs) specifically responded to TDZ, and a co-expression network analysis (WGCNA) showed five hub TFs (<i>GhNAC72</i>, <i>GhWRKY51</i>, <i>GhWRKY70</i>, <i>GhWRKY50</i>, and <i>GhHSF24</i>) during chemical defoliation with TDZ. Our work sheds light on the molecular basis of TDZ-induced leaf abscission in cotton. |
| first_indexed | 2024-03-11T04:55:21Z |
| format | Article |
| id | doaj.art-aa6fe5f9680a490484517d732ad4226b |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-11T04:55:21Z |
| publishDate | 2023-04-01 |
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| spelling | doaj.art-aa6fe5f9680a490484517d732ad4226b2023-11-17T19:42:45ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672023-04-01248759010.3390/ijms24087590Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus EthephonBaopeng Liao0Fangjun Li1Fei Yi2Mingwei Du3Xiaoli Tian4Zhaohu Li5Engineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, ChinaEngineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, ChinaEngineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, ChinaEngineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, ChinaEngineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, ChinaEngineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, ChinaThidiazuron (TDZ) is a widely used chemical defoliant in cotton and can stimulate the production of ethylene in leaves, which is believed to be the key factor in inducing leaf abscission. Ethephon (Eth) can also stimulate ethylene production in leaves, but it is less effective in promoting leaf shedding. In this study, the enzyme-linked immunosorbent assays (ELISA) and RNA-seq were used to determine specific changes at hormonal levels as well as transcriptomic mechanisms induced by TDZ compared with Eth. The TDZ significantly reduced the levels of auxin and cytokinin in cotton leaves, but no considerable changes were observed for Eth. In addition, TDZ specifically increased the levels of brassinosteroids and jasmonic acid in the leaves. A total of 13 764 differentially expressed genes that specifically responded to TDZ were identified by RNA-seq. The analysis of KEGG functional categories suggested that the synthesis, metabolism, and signal transduction of auxin, cytokinin, and brassinosteroid were all involved in the TDZ-induced abscission of cotton leaves. Eight auxin transport genes (<i>GhPIN1-c_D</i>, <i>GhPIN3_D</i>, <i>GhPIN8_A</i>, <i>GhABCB19-b_A</i>, <i>GhABCB19-b_D</i>, <i>GhABCB2-b_D</i>, <i>GhLAX6_A</i>, and <i>GhLAX7_D</i>) specifically responded to TDZ. The <i>pro35S::GhPIN3a::YFP</i> transgenic plants showed lower defoliation than the wild type treated with TDZ, and YFP fluorescence in leaves was almost extinguished after treatment with TDZ rather than Eth. This provides direct evidence that GhPIN3a is involved in the leaf abscission induced by TDZ. We found that 959 transcription factors (TFs) specifically responded to TDZ, and a co-expression network analysis (WGCNA) showed five hub TFs (<i>GhNAC72</i>, <i>GhWRKY51</i>, <i>GhWRKY70</i>, <i>GhWRKY50</i>, and <i>GhHSF24</i>) during chemical defoliation with TDZ. Our work sheds light on the molecular basis of TDZ-induced leaf abscission in cotton.https://www.mdpi.com/1422-0067/24/8/7590leaf abscissioncytokininbrassinosteroidauxin transporttranscription factorscotton |
| spellingShingle | Baopeng Liao Fangjun Li Fei Yi Mingwei Du Xiaoli Tian Zhaohu Li Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus Ethephon International Journal of Molecular Sciences leaf abscission cytokinin brassinosteroid auxin transport transcription factors cotton |
| title | Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus Ethephon |
| title_full | Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus Ethephon |
| title_fullStr | Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus Ethephon |
| title_full_unstemmed | Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus Ethephon |
| title_short | Comparative Physiological and Transcriptomic Mechanisms of Defoliation in Cotton in Response to Thidiazuron versus Ethephon |
| title_sort | comparative physiological and transcriptomic mechanisms of defoliation in cotton in response to thidiazuron versus ethephon |
| topic | leaf abscission cytokinin brassinosteroid auxin transport transcription factors cotton |
| url | https://www.mdpi.com/1422-0067/24/8/7590 |
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