Heat stress during seed development leads to impaired physiological function and plasticity in seed oil accumulation in Camelina sativa

Abstract

Camelina sativa, a member of the Brassicaceae, is a low-cost, renewable oilseed crop that produces seeds up to 40% oil by weight with high potential for use in food, feed, and biofuel applications. Camelina seeds contain high levels of the fatty acids α-linolenic acid (C18:3), linoleic acid (C18:2), oleic acid (C18:1), and gondoic acid (C20:1), which have high nutritional and industrial value. The impact of climate change, especially increased frequency and amplitude of heat waves, poses a serious threat to crop productivity. In this study, we evaluated the effect of elevated temperatures post-anthesis on the developing seeds of C. sativa and performed physiological, morphological, and chemical characterizations at 7, 14, 21, and 28 days post-anthesis (DPA), as well as at maturity. While the seed oil accumulation peaked at 21 DPA under control conditions, reaching 406mg/g dry weight, under heat stress it was only 186mg/g. Physiologically, transpiration rate (E) and internal CO2 concentration (Ci) increased between 2 to 9 days post-stress imposition and overall net photosynthesis was impaired. Seed yield, seed weight, and oil content reduced by 84.5%, 38.5% and 54.1% respectively. We demonstrate that post-anthesis heat stress causes severe yield losses and developmental plasticity in fatty acid accumulation in oilseeds.

Diversification of gene expression across extremophytes and stress-sensitive species in the Brassicaceae

“…Camelina sativa is an allohexaploid in the Brassicaceae lineage I that has emerged as an oil crop with a high promise for sustainable biofuel production. C. sativa can grow in diverse environments, but its overall growth, seed oil yield, and oil quality are severely impacted by salt and other abiotic stressors (Ahmed et al, 2020; Nadakuduti et al, 2023; Steppuhn et al, 2010). We generated a single cell atlas of 27,441 root cells from C. sativa under control, 5 µM ABA, and 100 mM NaCl, as described for the other four species (Figure 6).…”

Heat stress at the bicellular stage inhibits sperm cell development and transport into pollen tubes

“…Heat stress directly affects plant reproduction processes by decreasing the viability of reproductive cells ultimately leading to fertilization failures and sterility and thus declining plant productivity ( Chen et al 2016 ; Begcy et al 2019 ; Chaturvedi et al 2021 ; Kumar et al 2023 ; Nadakuduti et al 2023 ). Here, we show that HS applied exclusively either at the unicellular or bicellular stage of pollen development results in a strong reduction in seed set and yield.…”

“…Global warming is associated with hotter, longer, and more frequent heat waves. When these high temperature episodes occur during reproductive development in crop plants, a significant decrease in yield is commonly observed ( Folsom et al 2014 ; Chen et al 2016 ; Begcy et al 2019 ; Nadakuduti et al 2023 ). Within reproductive development, male gametophyte formation is one of the most susceptible stages ( De Storme and Geelen 2014 ; Begcy et al 2019 ; Chaturvedi et al 2021 ).…”