Stress Resilience in Coffea arabica and Coffea canephora under Harsh Drought and/or Heat Conditions: Genes, Proteins and Lipid Integrated Responses

José Cochicho Ramalho^1*Isabel Marques¹Isabel Pereira Pais²Jean ARMENGAUD³Duarte Domingos Gouveia³Ana Paula Rodrigues¹Danielly Dubberstein⁴António Eduardo Leitão¹Miroslava Rakocevic⁵Paula Scotti Campos⁶Sónia Martins⁷Magda C. Semedo⁷Fábio Luiz Partelli⁸Fernando José Cebola Lidon⁹Fábio M. DaMatta¹⁰Ana I Ribeiro-Barros^1*

• ¹Forest Research Centre, Higher Institute of Agronomy, University of Lisbon, Lisboa, Portugal
• ²Unidade de Investigação em Biotecnologia e Recursos Genéticos, Instituto Nacional de Investigação Agrária e Veterinária, I.P., Oeiras, Portugal
• ³Université Paris-Saclay, CEA, INRAE, Bagnols-sur-Cèze, France
• ⁴Assistência Técnica e Gerencial em Cafeicultura - Serviço Nacional de Aprendizagem Rural (SENAR), Porto Velho, Brazil
• ⁵Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Brazil
• ⁶Instituto Nacional de Investigação Agrária e Veterinária, I.P., Oeiras, Portugal
• ⁷Instituto Superior de Engenharia de Lisboa, Lisboa, Portugal
• ⁸Universidade Federal do Espirito Santo, São Mateus, Brazil
• ⁹Faculdade de Ciências e Tecnologia, Monte da Caparica, Portugal
• ¹⁰Universidade Federal de Viçosa, Viçosa, Brazil

Climate changes have intensified the frequency, severity and the simultaneous incidence of drought and heat events, threatening the sustainability of agricultural systems worldwide. This implies the use of resilient plant genotypes able to activate defence mechanisms and overcome stress damages. We examine leaf transcriptomic, proteomic and membrane lipid responses in two cultivars of the main coffee-producing species: Coffea arabica L. cv. Icatu and C. canephora Pierre ex A. Froehner cv. Conilon Clone 153 (CL153), subjected to single and combined exposure to severe water deficit (SWD) and heat (up to 42/30°C, day/night). Well-watered (WW) plants maintained under adequate temperature (25/20°C) were gradually exposed to SWD and afterwards to a slowly temperature rise up to 42/30°C, followed by a two-week recovery (Rec14) after reestablishing temperature and water conditions. Gene regulation and the respective protein contents were often marginally correlated but CL153 and, especially, Icatu showed markedly greater abundance of transcripts and/or proteins of most molecules to the imposed stress conditions, along with altered lipid profile of chloroplast membranes. A set of key complementary response mechanisms, expressed either commonly or in a genotype- or stress-dependent manner were identified. Additionally, common responses to all stress conditions reflected stress crosstalk and interaction. Drought (with or without heat superimposition) constituted a greater response driver than heat in both genotypes. These showed de novo synthesis of lipids and proteins, altering the fatty acids profile and unsaturation degree of chloroplast membranes, and strengthening oxidative stress protection. The latter involved several genes and their respective proteins (e.g., aquaporins, PIPs and TIPs; chaperonins, chape 20 and 60; dehydrin, DH1; dehydration responsive element binding protein, DREB1D-F1; early light-induced protein, ELIP; heat shock protein 70 kDa, HSP70; ascorbate peroxidases, APXs; catalase, CAT), particularly prominent in Icatu. Also, major recovery was found, though several genes/proteins exhibited lasting effects by Rec14. Overall, we reveal newly shared and specific (genotype or stress) responses of a complex network supporting Coffea spp. resilience. The identification of reliable stress-responsive traits is crucial to ensure the sustainability of this important tropical crop facing future climate stress scenarios, in which superimposed drought and heat stresses will be more frequent.