Transcriptomic analysis of cocoa (Theobroma cacao L.) response to water deficit.

Cocoa is a crop of cultural, nutritional and social importance in Latin America. Cocoa production is mainly supported by smallholders and is central for the food security of these farmer families. Despite being part of their everyday diet and an important source of antioxidants and other healthy bioactive compounds, cocoa cropping is also a solid source of stable incomes supporting the livelihood of farmer families. Water deficit stress is one of the main limiting factors affecting crop yields. The ability of plants to tolerate or recover from the effects associated with this abiotic stress is of immense importance in terms of improvement in the context of climate change. Despite the emergence of functional genomics and phenotyping tools to approach these responses, many of these mechanisms are still little understood for many tropical food crops such as cocoa. For a transcriptomic analysis were selected 2 cocoa genotypes, from a hydric stress assay established in a greenhouse. 5-month-old plants of T. cacao of the genotypes EET 8 and TSH565 were tested for water deficit trial. A divided plot experimental design was applied: the hydric state of the 2 genotypes was evaluated with two levels: field capacity and water deficit by irrigation suspension during a period that generates severe stress (Leaf Water Potential of -3.0 Mpa). The irrigation suspension lasted 52 days.