Baiyang Yu, Jianbin Liu, Di Wu, Ying Liu, Weijian Cen, Shaokui Wang, Rongbai Li & Jijing Luo

BMC Plant Biology volume 20, Article number: 478; Published: 20 October 2020

Background

Drought stress is an adverse factor with deleterious effects on several aspects of rice growth. However, the mechanism underlying drought resistance in rice remains unclear. To understand the molecular mechanism of the drought response in rice, drought-sensitive CSSL (Chromosome Single-substitution Segment Line) PY6 was used to map QTLs of sensitive phenotypes and to reveal the impact of the QTLs on transcriptional profiling.

Results

The QTL dss-1 was mapped onto the short arm of chromosome 1 of rice. According to transcriptomic analysis, the identified differentially expressed genes (DEGs) exhibited a downregulated pattern and were mainly enriched in photosynthesis-related GO terms, indicating that photosynthesis was greatly inhibited under drought. Further, according to weighted gene coexpression network analysis (WGCNA), specific gene modules (designating a group of genes with a similar expression pattern) were strongly correlated with H₂O₂ (4 modules) and MDA (3 modules), respectively. Likewise, GO analysis revealed that the photosynthesis-related GO terms were consistently overrepresented in H₂O₂-correlated modules. Functional annotation of the differentially expressed hub genes (DEHGs) in the H₂O₂ and MDA-correlated modules revealed cross-talk between abiotic and biotic stress responses for these genes, which were annotated as encoding WRKYs and PR family proteins, were notably differentially expressed between PY6 and PR403.

Conclusions

We speculated that drought-induced photosynthetic inhibition leads to H₂O₂ and MDA accumulation, which can then trigger the reprogramming of the rice transcriptome, including the hub genes involved in ROS scavenging, to prevent oxidative stress damage. Our results shed light on and provide deep insight into the drought resistance mechanism in rice.

See https://bmcplantbiol.biomedcentral.com/articles/10.1186/s12870-020-02705-9

Figure 7: Heat map and circular plot showing the altered expression and functional annotations of hub genes in the modules correlated with MDA accumulation. a Expression patterns and GO enrichment of hub genes of the module red. b Expression patterns and GO enrichment of hub genes of the module brown. c Expression patterns and GO enrichment of hub genes of the module royalblue. All the data used in the analysis were subjected to log2 transformation. Different colors represent hub gene-enriched corresponding GO terms