Welcome to Chinese Journal of Tropical Crops,

Chinese Journal of Tropical Crops ›› 2022, Vol. 43 ›› Issue (12): 2395-2404.DOI: 10.3969/j.issn.1000-2561.2022.12.001

• Omics & Biotechnology •     Next Articles

Cloning and Expression Analysis of HbRPW8 Gene from Hevea brasiliensis

GUAN Xin1,2, TU Min2,*(), CAI Haibin1,2, WANG Yunyue1,*(), HU Yanshi2, ZENG Xia2   

  1. 1. Plant Protection College, Yunnan Agricultural University, Kunming, Yunnan 650201, China
    2. Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou, Hainan 571101, China
  • Received:2022-03-11 Revised:2022-04-14 Online:2022-12-25 Published:2023-01-12
  • Contact: TU Min,WANG Yunyue


RPW8 (resistance to powdery mildew locus 8) is a broad-spectrum resistance gene locus to many plant diseases, especially powdery mildew. In this study, the cloning and expression analysis of RPW8 gene in Hevea brasiliensis were carried out to lay the foundation for the analysis of powdery mildew resistance mechanism and molecular breeding. HbRPW8 gene coding region (CDS) was cloned from rubber tree ‘Reyan 73397’ by RT-PCR. Bioinformatics analysis was carried out, and qRT-PCR method was used to determine the expression of RPW8 gene after seven hormones and powdery mildew infection at different times and disease grades. The full-length cDNA of HbRPW8 was 570 bp, encoding 189 amino acids. The molecular weight of HbRPW8 was 21.73 kDa, the isoelectric point was 9.23, the fat coefficient was 86.30, and the total average hydrophilicity index was -0.404, which was a hydrophilic protein with eight phosphorylation sites. The protein was located in the nucleus without transmembrane domain and signal peptide, and had a conserved domain of RPW8. The main components of the secondary structure of HbRPW8 protein were α-helix and random coil, accounting for 70.90% and 22.22% of the amino acid sequence, respectively. Phylogenetic relationships analysis showed that HbRPW8 gene had the highest similarity with cassava RPW8 gene. Hydrogen peroxide, salicylic acid, ethephon, gibberellin and abscisic acid could rapidly induce the expression of HbRPW8 transcript, and reached the highest level at 0.5 h after treatment, which was about 14, 6, 75, 2.5 and 4 folds of the control, respectively; methyl jasmonate treatment reached the highest level at 6 h after treatment, about 10 times that of the control; HbRPW8 transcript was significantly down-regulated after auxin treatment; with the increase of infection time and disease grade of powdery mildew, the expression level of HbRPW8 increased first and then decreased. The results of this study preliminarily showed that HbRPW8 may be involved in the resistance response mechanism of rubber tree, providing a reference for the study of rubber tree resistance breeding.

Key words: Hevea brasiliensis, HbRPW8 gene, qRT-PCR, bioinformatics, RPW8

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