Role In Thermal Response Research Articles

Negative Regulatory Role of Non-Coding RNA Vvi-miR3633a in Grapevine Leaves and Callus under Heat Stress

The grapevine, a globally significant fruit and an essential fruit tree species in China, is vulnerable to the adverse effects of high temperatures. Understanding the roles of microRNA and transcription factors in plant development and stress resistance is crucial for mitigating the impact of high temperature on grape growth and yield. This study investigates the response of miRNA to high-temperature stress in grape leaves. The expression level of Vvi-miR3633a was found to be inhibited under heat treatment in both Thompson seedless and Shen yue varieties, while its potential target genes (Vv-Atg36 and Vv-GA3ox2) were induced. Through transgenic overexpression experiments, it was demonstrated that Vvi-miR3633a plays a role in thermal response by affecting the expression of target genes. Furthermore, under heat stress conditions, overexpression of Vvi-miR3633a in grape callus decreased heat resistance compared to the control group (CK). The study also revealed that the target genes of Vvi-miR3633a regulate the expression of oxidase synthesis genes VvSOD and VvCAT, leading to reduced oxidase synthesis which may compromise the oxidation system. Additionally, the expression level of heat shock proteins in the transgenic lines was changed compared to the control (CK). Overall, this research provides valuable insights into understanding the molecular mechanisms involved in different crossing/breeding programs to produce heat-resistant grape varieties. Such varieties can be appropriate to propagate in warm climate areas with high temperature conditions.

The membrane-localized protein kinase MAP4K4/TOT3 regulates thermomorphogenesis

Plants respond to mild warm temperature conditions by increased elongation growth of organs to enhance cooling capacity, in a process called thermomorphogenesis. To this date, the regulation of thermomorphogenesis has been exclusively shown to intersect with light signalling pathways. To identify regulators of thermomorphogenesis that are conserved in flowering plants, we map changes in protein phosphorylation in both dicots and monocots exposed to warm temperature. We identify MITOGEN-ACTIVATED PROTEIN KINASE KINASE KINASE KINASE4 (MAP4K4)/TARGET OF TEMPERATURE3 (TOT3) as a regulator of thermomorphogenesis that impinges on brassinosteroid signalling in Arabidopsis thaliana. In addition, we show that TOT3 plays a role in thermal response in wheat, a monocot crop. Altogether, the conserved thermal regulation by TOT3 expands our knowledge of thermomorphogenesis beyond the well-studied pathways and can contribute to ensuring food security under a changing climate.

Role of brown adipose tissue in the thermal response to chlorpromazine in rats during cold exposure (author's transl)

Significance of the intercapsular brown adipose tissue (IBAT) in the thermal response to chlorpromazine (CPZ) during acute and chronic cold exposure was studied in rats. Adult male Wistar-Imamichi rats were exposed to 4 degrees C for 1 (cold-exposed) or 30 days (cold-acclimated). Intraperitoneal injection of 10 mg/kg CPZ caused a more marked and lasted hypothermia in acute cold-exposed rats as compared with that seen in control or in cold-acclimatized rats. Hypothermia induced by CPZ was unaffected by removal of IBAT either in control or acute cold-exposed rats. But in cold-acclimated rats, the removal of IBAT potentiated the hypothermia by CPZ. The relative weight of IBAT in cold-acclimated rats was about 3 times heavier than that in control and acute cold-exposed rats. CPZ had no effect on the relative weight of IBAT in all groups examined. Total lipids in IBAT showed no significant changes following CPZ administration in rats of all groups. In acute cold-exposed rats, serum FFA level progressively decreased after CPZ injection. The noradrenaline concentration in IBAT increased after chronic cold exposure and CPZ suppressed this elevation. The results suggest that the thermogenesis related sympathetic activity in the IBAT plays a mediatory role in thermal response to CPZ during cold acclimation.