Zhimin Lin, Xiaoyan Yi, Muhammad Moaaz Ali, Lijuan Zhang, Shaojuan Wang, Shengnan Tian, Faxing Chen

Int J Mol Sci.; 2024 Jan 20; 25(2):1284. doi: 10.3390/ijms25021284.

Abstract

This study explores the impact of RNAi in terms of selectively inhibiting the expression of the OsBBTI5 gene, with the primary objective of uncovering its involvement in the molecular mechanisms associated with salt tolerance in rice. OsBBTI5, belonging to the Bowman-Birk inhibitor (BBI) family gene, is known for its involvement in plant stress responses. The gene was successfully cloned from rice, exhibiting transcriptional self-activation in yeast. A yeast two-hybrid assay confirmed its specific binding to OsAPX2 (an ascorbate peroxidase gene). Transgenic OsBBTI5-RNAi plants displayed insensitivity to varying concentrations of 24-epibrassinolide in the brassinosteroid sensitivity assay. However, they showed reduced root and plant height at high concentrations (10 and 100 µM) of GA₃ immersion. Enzyme activity assays revealed increased peroxidase (POD) and superoxide dismutase (SOD) activities and decreased malondialdehyde (MDA) content under 40-60 mM NaCl. Transcriptomic analysis indicated a significant upregulation of photosynthesis-related genes in transgenic plants under salt stress compared to the wild type. Notably, this study provides novel insights, suggesting that the BBI gene is part of the BR signaling pathway, and that OsBBTI5 potentially enhances stress tolerance in transgenic plants through interaction with the salt stress-related gene OsAPX2.

See https://pubmed.ncbi.nlm.nih.gov/38279284/

Figure 1. (A) Cluster analysis of the rice BBI family with homologs from Brachypodium distachyon, Zea mays and Glycine max. The four species are represented in red, blue, orange, and purple, respectively. (B) Structural domain analysis of BBI amino acids in rice. (C) Analysis of transcription factor binding sites of BBI family genes in rice. (D) Exon analysis of rice BBI family genes.