Cardiac performance in heat-stressed flies of heat-susceptible and heat-resistant Drosophila melanogaster

• Published in: Journal of insect physiology 2021-08, Vol.133, p.104268-104268, Article 104268
• Main Authors: Rodríguez, Maia, Pagola, Lucía, Norry, Fabian M., Ferrero, Paola
• Format: Article
• Language: English
• Subjects: Cardiac susceptibility; Heart performance; Heart proteins; Heat susceptibility; Thermal adaptation; Thermotolerance
• ISSN: 0022-1910; 1879-1611
• DOI: 10.1016/j.jinsphys.2021.104268

[Display omitted] •Heart performance was tested in heat-resistant (HR) and susceptible (HS) fly stocks.•Arrhythmia and bradycardia in heat-stressed flies were higher in HS than HR strains.•In HS strain, heat-stressed flies exhibited higher contractility and longer relaxation.•Activity level of SERCA, RyR and NCX did not differ between HR and HS flies.•Heart performance could be linked to quantitative trait loci for thermotolerance. Thermotolerance is a complex trait that can greatly differ between heat-susceptible (HS) and heat-adapted populations of small insects including Drosophila, with short-term effects after a sub-lethal level of heat stress on many physiological functions. Cardiac performance could accordingly be more robust in heat-resistant (HR) than in HS individuals under heat stress. Here, we tested heart performance under heat-stress effects in two recombinant inbred lines (RIL) of Drosophila melanogaster that dramatically differ in heat knockdown resistance. Heart rate did not strongly differ between heat-susceptible and heat-tolerant flies after a sub-lethal heat stress. Instead, heat-susceptible flies showed a much higher arrhythmia incidence, a longer duration of each heartbeat, and a larger amount of bradycardia than heat-tolerant flies. The highly conserved cardiac proteins SERCA, RyR and NCX that participate in the excitation/contraction coupling, did not differ in activity level between HR and HS flies. Available information for both RIL suggests that heart performance under heat stress may be linked, at least partially, to candidate genes of previously identified quantitative trait loci (QTL) for thermotolerance. This study indicates that HR flies can be genetically more robust in their heart performance than HS flies under even sub-lethal levels of heat stress.