Metabolic Dynamics of Developing Rice Seeds Under High Night-Time Temperature Stress

Authors

Balpreet K. Dhatt, University of Nebraska-Lincoln
Nathan Abshire, University of Nebraska-LincolnFollow
Puneet Paul, University of Nebraska-Lincoln, LincolnFollow
Kalani Hasanthika, University of Nebraska- Lincoln
Jaspreet Sandhu, University of Nebraska-LincolnFollow
Qi Zhang, University of Nebraska-LincolnFollow
Toshihiro Obata, University of Nebraska-LincolnFollow
Harkamal Walia, University of Nebraska-LincolnFollow

Date of this Version

11-8-2019

Citation

Dhatt BK, Abshire N, Paul P, Hasanthika K, Sandhu J, Zhang Q, Obata T and Walia H (2019) Metabolic Dynamics of Developing Rice Seeds Under High Night-Time Temperature Stress. Front. Plant Sci. 10:1443. doi: 10.3389/fpls.2019.01443

Abstract

High temperature stress during rice reproductive development results in yield losses. Reduced grain yield and grain quality has been associated with high temperature stress, and specifically with high night-time temperatures (HNT). Characterizing the impact of HNT on the phenotypic and metabolic status of developing rice seeds can provide insights into the mechanisms involved in yield and quality decline. Here, we examined the impact of warmer nights on the morphology and metabolome during early seed development in six diverse rice accessions. Seed size was sensitive to HNT in four of the six genotypes, while seed fertility and seed weight were unaffected. We observed genotypic differences for negative impact of HNT on grain quality. This was evident from the chalky grain appearance due to impaired packaging of starch granules. Metabolite profiles during early seed development (3 and 4 days after fertilization; DAF) were distinct from the early grain filling stages (7 and 10 DAF) under optimal conditions. We observed that accumulation of sugars (sucrose, fructose, and glucose) peaked at 7 DAF suggesting a major flux of carbon into glycolysis, tricarboxylic acid cycle, and starch biosynthesis during grain filling. Next, we determined hyper (HNT > control) and hypo (HNT < control) abundant metabolites and found 19 of the 57 metabolites to differ significantly between HNT and control treatments. The most prominent changes were exhibited by differential abundance of sugar and sugar alcohols under HNT, which could be linked to a protective mechanism against the HNT damage. Overall, our results indicate that combining metabolic profiles of developing grains with yield and quality parameters under high night temperature stress could provide insight for exploration of natural variation for HNT tolerance in the rice germplasm.