Primary metabolite profile changes in coffea spp. Promoted by single and combined exposure to drought and elevated co₂ concentration

Climate change scenarios pose major threats to many crops worldwide, including coffee. We explored the primary metabolite responses in two Coffea genotypes, C. canephora cv. Conilon Clone 153 and C. arabica cv. Icatu, grown at normal (aCO₂) or elevated (eCO₂) CO₂ concentrations of 380 or 700 ppm, respectively, under well-watered (WW), moderate (MWD), or severe (SWD) water deficit conditions, in order to assess coffee responses to drought and how eCO2 can influence such responses. Primary metabolites were analyzed with a gas chromatography time-of-flight mass spectrometry metabolomics platform (GC-TOF-MS). A total of 48 primary metabolites were identified in both genotypes (23 amino acids and derivatives, 10 organic acids, 11 sugars, and 4 other metabolites), with differences recorded in both genotypes. Increased metabolite levels were observed in CL153 plants under single and combined conditions of aCO₂ and drought (MWD and SWD), as opposed to the observed decreased levels under eCO₂ in both drought conditions. In contrast, Icatu showed minor differences under MWD, and increased levels (especially amino acids) only under SWD at both CO₂ concentration conditions, although with a tendency towards greater increases under eCO₂. Altogether, CL153 demonstrated large impact under MWD, and seemed not to benefit from eCO₂ in either MWD and SWD, in contrast with Icatu.