Functional Analysis of Rice Heat Shock Transcription Factor HsfA2b Regulating the Resistance to Abiotic Stresses

doi:10.13560/j.cnki.biotech.bull.1985.2023-0908

Abstract

Abstract:

【Objective】 Rice is often affected by various abiotic stresses during growth and development, which severely restricts rice yield. Heat shock transcription factors（HSFs）, as an important element of resistance to abiotic stresses in plant, can enhance plant resistance to abiotic stresses by regulating the expressions of a series of stress related genes. This study aims to investigate the function and mechanism of rice heat shock transcription factor OsHsfA2b regulating abiotic stresses, which may provide excellent gene resource and theoretical support for cultivating new rice varieties with stress resistance.【Method】 We constructed OsHsfA2b-overexpressed and RNAi rice transgenic plants, then their seedlings were treated with high temperature, low temperature, drought, and high salt, respectively, and their phenotypes were observed and survival rates were counted. The detection of reactive oxygen species（ROS）deposition by DAB staining, and expression levels of antioxidant pathway related genes OsSOD and OsCAT with RT-qPCR after abiotic stress treatment, aiming to analyze the regulatory effect of OsHsfA2b on the antioxidant pathway.【Result】 The rice HSF gene OsHsfA2b was induced significantly by abiotic stress conditions, such as high temperature, low temperature, drought, and high salt. Compared with the wild-type plants, OsHsfA2b-overexpressed transgenic plants significantly enhanced the resistance to abiotic stresses, as well as survival rate, and less damage. On the contrary, both resistance and survival rate of OsHsfA2b-RNAi plants to abiotic stresses decreased, and the plants were severely damaged. Moreover, the ROS deposition in OsHsfA2b-overexpressed plants decreased compared with NPB and RNAi plants under abiotic stress. Correspondingly, OsHsfA2b induced the expressions of antioxidant pathway related genes OsSOD and OsCAT, suggesting that OsHsfA2b suppressed ROS accumulation to reduce its damage caused by abiotic stress induction.【Conclusion】 The above results indicate that OsHsfA2b is induced by abiotic stresses and positively regulates rice resistance to abiotic stresses through antioxidant pathways, and it is an excellent gene resource for rice stress-resistance breeding.

Key words: Oryza sativa L., HsfA2b, heat shock transcription factor, abiotic stress, resistance, reactive oxygen species

ZOU Xiu-wei, YUE Jia-ni, LI Zhi-yu, DAI Liang-ying, LI Wei. Functional Analysis of Rice Heat Shock Transcription Factor HsfA2b Regulating the Resistance to Abiotic Stresses[J]. Biotechnology Bulletin, 2024, 40(2): 90-98.

Figures/Tables 8

Table 1 Primers for RT-qPCR

引物Primer	序列Sequence（5'-3'）
UBQ-F	AACCAGCTGAGGCCCAAGA
UBQ-R	ACGATTGATTTAACCAGTCCATGA
OsHsfA2b-F	GCCTTGTTTGATCCCCAGGA
OsHsfA2b-R	TTGTCGTTCAACTCCCCCTG
OsSOD-F	AACAAAGGCAGGGCTGTAGA
OsSOD-R	TAAGGTTCCAGGGCATCAAG
OsCAT-F	TGAAGCCAAGCATGTGAAGA
OsCAT-R	GCCCAACGACAACAGAAGAT

Fig. 1 Electropherogram of OsHsfA2b gene CDS amplification M: Marker; N: negative control; 1: OsHsfA2b full-length CDS amplified fragment

Fig. 2 Protein structure of OsHsfA2b The number above the structural diagram represents the position of amino acids. DBD: DNA binding domain; OD: oligomerization domain; NLS: nuclear localization signal; CTAD: C-terminal transcriptional activation domain; NES: nuclear export signal

Fig. 3 Identification of OsHsfA2b-OX and OsHsfA2b-RNAi transgenic plants A: OsHsfA2b gene expression of OsHsfA2b-OX transgenic plants. B: OsHsfA2b gene expression of OsHsfA2b-RNAi transgenic plants

Fig. 4 Phenotypes and OsHsfA2b expressions of transgenic plants under high temperature stress A: Expression of OsHsfA2b in NPB under high temperature stress（42℃）. B: Expression of OsSOD after high temperature treatment. C: Phenotypes of plants after high temperature treatment for 2 d after high temperature treatment. D: Survival rate statistic. E: Expression of OsCAT after high temperature treatment. F: Determination of reactive oxygen species content. * indicates significant difference（P<0.05）, and **indicates extremely significant difference（P<0.01）. The same below

Fig. 5 Phenotypes and OsHsfA2b expressions of transgenic plants under low temperature stress A: Expression of OsHsfA2b under low temperature stress（4℃）. B: Phenotypes of plants after low temperature treatment for 2 d. C: Survival rate statistic. D-E: Expression of OsSOD and OsCAT after low temperature treatment

Fig. 6 Phenotypes and OsHsfA2b expressions of transgenic plants under drought stress A: Expression of OsHsfA2b under drought treatment. B: Phenotypes of plants after drought treatment for 1 d. C: Survival rate statistic. D-E: Expression of OsSOD and OsCAT after drought treatment

Fig. 7 Phenotypes and OsHsfA2b expressions of transgenic plants under high salt stress A: Expression of OsHsfA2b under 150 mmol/L NaCl. B: Phenotypes of seedlings geminated after 150 mmol/L NaCl for 5 d. C: Phenotypes of plants under 150 mmol/L NaCl for 2 d. D-E: Expression of OsSOD and OsCAT after high salt treatment

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