Interplay of rice vitamin E under osmotic and extreme temperature stresses revealed by a comparative transcriptomic approach.

Background: Rice (Oryza sativa L.) is vulnerable to abiotic challenges. Understanding stress response mechanisms is therefore a priority for enhancing rice development. Tocopherol is a known antioxidant that helps plants adapt to various abiotic stresses. We analysed bibliographic data from 13 years of studies on abiotic stresses. We also performed a meta-analysis of 231 microarray samples from 12 different studies on genotypes sensitive and tolerant to drought, salinity, heat, and heat-related effects on vitamin E biosynthesis in rice. Common differentially expressed genes (DEGs - 30) were identified with p-value < 0.05 and |log₂FC| > 1. An in silico expression analysis of the DEGs and a Protein-Protein Interaction (PPI) network analysis were performed using bioinformatics tools.

Results: Our findings showed that 13 structural Genes and 17 transcription factors, including OsGGPPS1, isochorismatase hydrolase, aminotransferase, OsVTE3, shikimate kinase, and the families of bHLH, WRKY, bZIP, and C2H2 transcription factors, are all involved in vitamin E biosynthesis under drought, cold, and heat stresses in rice. OsWRKY77 was commonly expressed in both cold and heat-sensitive genotypes, and in aminotransferase between drought and cold in tolerant genotypes.

Conclusions: The analysis showed that abiotic stresses, except for salt stress, induce genes involved in vitamin E biosynthesis. Cold stress induced more intense molecular responses compared to other types of stress. Our results can provide insight into the regulatory mechanisms involved in response to selected abiotic stresses, which ultimately can contribute to the development of stress-resistant or tolerant rice cultivars.