Huang Zhou, Yingfeng Wang, Yijin Zhang, Yunhua Xiao, Xiong Liu, Huabing Deng, Xuedan Lu, Wenbang Tang, Guilian Zhang.

Plants (Basel); 2022 Apr 13;11(8):1062.  doi: 10.3390/plants11081062.

Abstract

To elucidate the mechanism underlying the response of rice to heat stress (HS), the transcriptome profile of panicles was comparatively analyzed between the heat-tolerant line 252 (HTL252) and heat-susceptible line 082 (HSL082), two rice recombinant inbred lines (RILs). Our differentially expressed gene (DEG) analysis revealed that the DEGs are mainly associated with protein binding, catalysis, stress response, and cellular process. The MapMan analysis demonstrated that the heat-responsive (HR) genes for heat shock proteins, transcription factors, development, and phytohormones are specifically induced in HTL252 under HS. Based on the DEG analysis, the key gene OsNCED1 (Os02g0704000), which was induced under HS, was selected for further functional validation. Moreover, 9-cis-epoxycarotenoid dioxygenase (NCED) is a key rate-limiting enzyme in the ABA biosynthetic pathway. Overexpression of OsNCED1 improved the HS tolerance of rice at the heading and flowering stage. OsNCED1-overexpression plants exhibited significant increases in pollen viability, seed setting rate, superoxide dismutase (SOD) and peroxidase (POD) activities, while significantly lower electrolyte leakage and malondialdehyde (MDA) content relative to the wild type (WT). These results suggested that OsNCED1 overexpression can improve the heat tolerance of rice by enhancing the antioxidant capacity. Overall, this study lays a foundation for revealing the molecular regulatory mechanism underlying the response of rice to prolonged HS.

See: https://pubmed.ncbi.nlm.nih.gov/35448790/

Figure 3

(A) Heat map of DEGs associated with heat shock protein genes in HTL252 and HSL082 after 5 d of HS treatment based on the expression levels. The red color represents upregulated genes, and the green color represents downregulated genes. (B) Expression profiles of phytohormone-related HR genes based on fold changes. The blue color represents low-level expression, light yellow color represents medium level, and red color represents the highest level. The fold change is the ratio of the signal value of the high temperature sample to that of the optimum temperature sample.