Guanosine tetraphosphate (ppGpp) is a new player in $Brassica\ napus$ L. seed development

Sena Turkan (1, 2) , Milena Kulasek (2, 1) , Agnieszka Zienkiewicz (2, 1) , Agnieszka Mierek-Adamska (2, 1) , Edyta Skrzypek (3) , Marzena Warchoł (3) , Aleksandra Szydłowska-Czerniak (1) , Julia Bartoli (4, 5) , Ben Field (6, 7) , Grażyna B Dąbrowska (2, 1)

1 Nicolaus Copernicus University [Toruń]
2 Department of Genetics, Faculty of Biological and Veterinary Sciences, Nicolaus Copernicus University, Torun
3 The Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków, Poland
4 LISM - Laboratoire d'ingénierie des systèmes macromoléculaires
5 IMM - Institut de Microbiologie de la Méditerranée
6 LGBP - Luminy Génétique et Biophysique des Plantes
7 BIAM - Institut de Biosciences et Biotechnologies d'Aix-Marseille (ex-IBEB)

Rapeseed oil, constituting 12% of global vegetable oil production, is susceptible to quality degradation due to stress-induced incomplete seed degreening, fatty acid oxidation, or poor nutrient accumulation. We hypothesise that the hyperphosphorylated nucleotide alarmone ppGpp (guanosine tetraphosphate), acts as a pivotal regulator of these processes, given its established roles in nutrient management, degreening, and ROS regulation in leaves. Using qPCR, UHPLC-MS/MS, and biochemical methods, our study delves into the impact of ppGpp on seed nutritional value. We observed a positive correlation between ppGpp levels and desiccation, and a negative correlation with photosynthetic pigment levels. Trends in antioxidant activity suggest that ppGpp may negatively influence peroxidases, thereby safeguarding against chlorophyll decomposition. Notably, despite increasing ppGpp levels, sugars, proteins and oils appear unaffected. This newfound role of ppGpp in seed development suggests it regulates the endogenous antioxidant system during degreening and desiccation, preserving nutritional quality. Further validation through mutant-based research is needed.

Keywords: Food Chemistry

Domains: Life Sciences [q-bio]

Sena Turkan, Milena Kulasek, Agnieszka Zienkiewicz, Agnieszka Mierek-Adamska, Edyta Skrzypek, et al.. Guanosine tetraphosphate (ppGpp) is a new player in $Brassica\ napus$ L. seed development. Food Chemistry, inPress, pp.137648. ⟨10.1016/j.foodchem.2023.137648⟩. ⟨hal-04235248v1⟩