CaHsfA1d Improves Plant Thermotolerance via Regulating the Expression of Stress- and Antioxidant-Related Genes

Abstract

Heat shock transcription factor (Hsf) plays an important role in regulating plant thermotolerance. The function and regulatory mechanism of CaHsfA1d in heat stress tolerance of pepper have not been reported yet. In this study, phylogenetic tree and sequence analyses confirmed that CaHsfA1d is a class A Hsf. CaHsfA1d harbored transcriptional function and predicted the aromatic, hydrophobic, and acidic (AHA) motif mediated function of CaHsfA1d as a transcription activator. Subcellular localization assay showed that CaHsfA1d protein is localized in the nucleus. The CaHsfA1d was transcriptionally up-regulated at high temperatures and its expression in the thermotolerant pepper line R9 was more sensitive than that in thermosensitive pepper line B6. The function of CaHsfA1d under heat stress was characterized in CaHsfA1d-silenced pepper plants and CaHsfA1d-overexpression Arabidopsis plants. Silencing of the CaHsfA1d reduced the thermotolerance of the pepper, while CaHsfA1d-overexpression Arabidopsis plants exhibited an increased insensitivity to high temperatures. Moreover, the CaHsfA1d maintained the H2O2 dynamic balance under heat stress and increased the expression of Hsfs, Hsps (heat shock protein), and antioxidant gene AtGSTU5 (glutathione S-transferase class tau 5) in transgenic lines. Our findings clearly indicate that CaHsfA1d improved the plant thermotolerance via regulating the expression of stress- and antioxidant-related genes.

ZmNAC074, a maize stress-responsive NAC transcription factor, confers heat stress tolerance in transgenic Arabidopsis

“…The total RNA was isolated with Trizol reagent (TIANGEN, China) ( Gai et al., 2020 ). The first strand of cDNA was synthesized from 2μg of total RNA using the FastKing RT Kit (TIANGEN, China).…”

HsfA1a confers pollen thermotolerance through upregulating antioxidant capacity, protein repair, and degradation in Solanum lycopersicum L.

“…Among various SOD enzymes, Cu/Zn-SOD is identified as the central component in regulating total SOD activity in rice anthers [ 12 ]. Previous studies have demonstrated the links between antioxidant enzymes and Hsfs in redox regulation [ 13 , 14 ]. PuHSFA4a increased glutathione S-transferase (GST) activity by binding to the promoter of PuGSTU17 in Populus ussuriensis to reduce ROS acumination and promote excess Zn tolerance [ 13 ].…”

“…PuHSFA4a increased glutathione S-transferase (GST) activity by binding to the promoter of PuGSTU17 in Populus ussuriensis to reduce ROS acumination and promote excess Zn tolerance [ 13 ]. Heterologous expression of CaHsfA1d in Arabidopsis enhanced the expression of Hsfs and the antioxidant gene AtGSTU5 , thereby maintaining H 2 O 2 homeostasis and improving plant thermotolerance [ 14 ]. However, Hsf-mediated redox regulation in pollen under heat stress is largely unknown.…”

BrPP5.2 Overexpression Confers Heat Shock Tolerance in Transgenic Brassica rapa through Inherent Chaperone Activity, Induced Glucosinolate Biosynthesis, and Differential Regulation of Abiotic Stress Response Genes

“…Heat stress upregulated most HSR genes at the transcriptional level, which usually had opposite expression patterns under standard growth conditions. The overexpression of many of these HSR genes, such as DDF1 [ 27 ], ATHSFA2 [ 28 ], AT-HSFB2A [ 29 ], BIP3 [ 30 ], MIPS2 [ 31 ], HSP17.6II [ 32 ], HSP17.6B-CI [ 33 ], Hsp70b [ 34 ], HSP70 [ 35 ], and CYP71B2 [ 36 ], would facilitate improved tolerance to heat stress. Thus, we conclude that the overexpression of HSR genes during heat stress may contribute to BrPP5.2-mediated heat stress tolerance.…”