A High Temperature-Dependent Mitochondrial Lipase EXTRA GLUME1 Promotes Floral Phenotypic Robustness against Temperature Fluctuation in Rice (Oryza sativa L.)

Abstract

The sessile plants have evolved diverse intrinsic mechanisms to control their proper development under variable environments. In contrast to plastic vegetative development, reproductive traits like floral identity often show phenotypic robustness against environmental variations. However, it remains obscure about the molecular basis of this phenotypic robustness. In this study, we found that eg1 (extra glume1) mutants of rice (Oryza savita L.) showed floral phenotypic variations in different growth locations resulting in a breakdown of floral identity robustness. Physiological and biochemical analyses showed that EG1 encodes a predominantly mitochondria-localized functional lipase and functions in a high temperature-dependent manner. Furthermore, we found that numerous environmentally responsive genes including many floral identity genes are transcriptionally repressed in eg1 mutants and OsMADS1, OsMADS6 and OsG1 genetically act downstream of EG1 to maintain floral robustness. Collectively, our results demonstrate that EG1 promotes floral robustness against temperature fluctuation by safeguarding the expression of floral identify genes through a high temperature-dependent mitochondrial lipid pathway and uncovers a novel mechanistic insight into floral developmental control.

Ethylene-Inhibited Jasmonic Acid Biosynthesis Promotes Mesocotyl/Coleoptile Elongation of Etiolated Rice Seedlings

“…The Arabidopsis homolog DAD1 and DGL-mediated JA biosynthesis regulates floral development (Ishiguro et al, 2001;Hyun et al, 2008). A gy1 allelic mutant extra glume1 (eg1) also exhibits an abnormal number of pistils and an extra glume-like organ in rice (Li et al, 2009;Zhang et al, 2016). The abnormal flower development of the gy1 mutant may cause the reduction of yield-related traits (Supplemental Table 2).…”

One Heat Shock Transcription Factor Confers High Thermal Tolerance in Clematis Plants

“…Heat shock proteins also play an important role in response to thermal stress. Heat treatment greatly increased HSP90 expression, which directly interacted with transport inhibitor response 1 (TIR1) to prevent its degradation and modulate auxin-mediated plant growth [ 37 , 38 ]. It has been reported that HSFs function upstream of HSPs in heat response [ 32 , 33 ].…”

Enhancement of Heat and Drought Stress Tolerance in Rice by Genetic Manipulation: A Systematic Review

“…The other reason is non-stomatal restriction. Stress inhibits photosynthesis by affecting the activity of Rubisco and the PSII structure of the photosystem (Zhang et al 2016 ). Chlorophyll content is one of the most widely used physiological indicators because it directly affects the efficiency of photosynthesis (Croft et al 2017 ).…”

“…The accumulation of some metabolites has a significant contribution to the process of high temperature tolerance. The lipase gene EG1 , localized in the mitochondria and plastids, mediates the mitochondrial lipase pathway under high temperature, regulating lipid metabolism and downstream gene expression (Zhang et al 2016 ). High cytoplasmic levels of Ca 2+ promote heat tolerance in plants.…”