Abstract
High temperature stress (HTS) is a serious threat to plant growth and development and to crop production in the context of global warming, and plant response to HTS is largely regulated at the transcriptional level by the actions of various transcription factors (TFs). However, whether and how homeodomain-leucine zipper (HD-Zip) TFs are involved in thermotolerance are unclear. Herein, we functionally characterized a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15. CaHDZ15 expression was upregulated by HTS and abscisic acid in basal thermotolerance via loss- and gain-of-function assays by virus-induced gene silencing in pepper and overexpression in Nicotiana benthamiana plants. CaHDZ15 acted positively in pepper basal thermotolerance by directly targeting and activating HEAT SHOCK FACTORA6a (HSFA6a), which further activated CaHSFA2. In addition, CaHDZ15 interacted with HEAT SHOCK PROTEIN 70-2 (CaHsp70-2) and glyceraldehyde-3-phosphate dehydrogenase1 (CaGAPC1), both of which positively affected pepper thermotolerance. CaHsp70-2 and CaGAPC1 promoted CaHDZ15 binding to the promoter of CaHSFA6a, thus enhancing its transcription. Furthermore, CaHDZ15 and CaGAPC1 were protected from 26S proteasome-mediated degradation by CaHsp70-2 via physical interaction. These results collectively indicate that CaHDZ15, modulated by the interacting partners CaGAPC1 and CaHsp70-2, promotes basal thermotolerance by directly activating the transcript of CaHSFA6a. Thus, a molecular linkage is established among CaHsp70-2, CaGAPC1, and CaHDZ15 to transcriptionally modulate CaHSFA6a in pepper thermotolerance.
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Claims 12
Claim · model-written summary
Heat stress upregulated CaHDZ15 expression.
Not reportedComparator
Verbatim
e0“CaHDZ15 expression was upregulated by HTS and abscisic acid”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”
Claim · model-written summary
Abscisic acid upregulated CaHDZ15 expression.
Not reportedComparator
Verbatim
e0“CaHDZ15 expression was upregulated by HTS and abscisic acid”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”
Claim · model-written summary
CaHDZ15 positively regulated pepper basal thermotolerance.
Verbatim
e0“CaHDZ15 acted positively in pepper basal thermotolerance”
Claim · model-written summary
CaHDZ15 directly targeted and activated HSFA6a, which further activated CaHSFA2.
Verbatim
e0“pepper basal thermotolerance by directly targeting and activating HEAT SHOCK FACTORA6a (HSFA6a), which further activated CaHSFA2.”
e1“CaHDZ15 acted positively in pepper basal thermotolerance”
Claim · model-written summary
CaHDZ15 interacted with CaHsp70-2.
Verbatim
e0“CaHDZ15 interacted with HEAT SHOCK PROTEIN 70-2 (CaHsp70-2) and glyceraldehyde-3-phosphate dehydrogenase1 (CaGAPC1)”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”
Claim · model-written summary
CaHDZ15 interacted with CaGAPC1.
Verbatim
e0“CaHDZ15 interacted with HEAT SHOCK PROTEIN 70-2 (CaHsp70-2) and glyceraldehyde-3-phosphate dehydrogenase1 (CaGAPC1)”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”
Claim · model-written summary
CaHsp70-2 positively affected pepper thermotolerance.
Verbatim
e0“CaHDZ15 interacted with HEAT SHOCK PROTEIN 70-2 (CaHsp70-2) and glyceraldehyde-3-phosphate dehydrogenase1 (CaGAPC1), both of which positively affected pepper thermotolerance.”
Claim · model-written summary
CaGAPC1 positively affected pepper thermotolerance.
Verbatim
e0“CaHDZ15 interacted with HEAT SHOCK PROTEIN 70-2 (CaHsp70-2) and glyceraldehyde-3-phosphate dehydrogenase1 (CaGAPC1), both of which positively affected pepper thermotolerance.”
Claim · model-written summary
CaHsp70-2 promoted CaHDZ15 binding to the CaHSFA6a promoter and enhanced transcription.
Verbatim
e0“CaHsp70-2 and CaGAPC1 promoted CaHDZ15 binding to the promoter of CaHSFA6a, thus enhancing its transcription.”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”
Claim · model-written summary
CaGAPC1 promoted CaHDZ15 binding to the CaHSFA6a promoter and enhanced transcription.
Verbatim
e0“CaHsp70-2 and CaGAPC1 promoted CaHDZ15 binding to the promoter of CaHSFA6a, thus enhancing its transcription.”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”
Claim · model-written summary
CaHsp70-2 protected CaHDZ15 from proteasome-mediated degradation through physical interaction.
Verbatim
e0“CaHDZ15 and CaGAPC1 were protected from 26S proteasome-mediated degradation by CaHsp70-2 via physical interaction.”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”
Claim · model-written summary
CaHsp70-2 protected CaGAPC1 from proteasome-mediated degradation through physical interaction.
Verbatim
e0“CaHDZ15 and CaGAPC1 were protected from 26S proteasome-mediated degradation by CaHsp70-2 via physical interaction.”
e1“a pepper (Capsicum annuum) HD-Zip I TF CaHDZ15”