Gallego Adriana M, Zambrano Romer A, Zuluaga Martha, Camargo Rodríguez Anyela V, Candamil Cortés Mariana S, Romero Vergel Angela P, Arboleda Valencia Jorge W
Grupo de Biotecnología, Instituto de Biología, Universidad de Antioquia, Medellín, Colombia; Centro de Bioinformática y Biología Computacional de Colombia-BIOS, Manizales, Colombia.
Facultad de Ingeniería y Arquitectura, Universidad Nacional, Sede Manizales, Colombia.
Phytochemistry. 2022 Nov;203:113412. doi: 10.1016/j.phytochem.2022.113412. Epub 2022 Aug 31.
The pod husk of Theobroma cacao (CPH) plays an important agronomical role, as its appearance is used as indicator of ripening, guiding the farmers in the harvest process. Cacao harvesting is not a standardized practice because farmers harvest between six up to eight months from flowering, guided by pod's color and shape. The mixture of cacao beans from different ripening stages (RS), negatively affecting the quality and price of grain. A way to help the farmers in the harvest standardization could be through the use of chemical markers and visual indicators of CPH ripening. This study analyses CPH's metabolic distribution of two cacao clones, ICS95 and CCN51 at six, seven, and eight months of ripening. Untargeted metabolomics was done using HPLC-MS/MS for biomarker discovery and association to cacao ripening. The results indicated a strong metabolic differentiation of the sixth month with the rest of the months independent of the variety. Also, metabolic differences were found between cacao clones for the seventh and eighth month. We annotated five potential biochemical markers including 3-caffeoylpelargodinin 5-glucoside, indoleacetaldehyde, procyanidin A dimer, procyanidin C1, and kaempferol. We further looked for correlation between patterns of progression of our markers against quantitative indicators of CPH appearance and texture, at the same ripening stages. We also performed a functional analysis and three possible metabolic pathways: flavone and flavonol biosynthesis, flavonoid biosynthesis, and tryptophan metabolism were identified associated with stress sensing, plant development and defense respectively. We found significant and positive correlations between green color density and all metabolites. For texture, the correlations were significantly negative with all metabolites. Our results suggest that about the sixth month is appropriate for harvesting cacao in the region of Caldas, Colombia in order to avoid all the metabolic variations occurring at later stages of ripening which impact the cacao bean quality. Therefore, studying the cacao ripening process can help in the estimation of the best harvest time and contribute to the standardization of harvest practices.
可可树（Theobroma cacao）的豆荚外壳（CPH）起着重要的农艺学作用，因为其外观被用作成熟度的指标，指导农民进行收获过程。可可收获并非标准化操作，因为农民在开花后六至八个月之间进行收获，依据豆荚的颜色和形状来判断。来自不同成熟阶段（RS）的可可豆混合在一起，会对谷物的质量和价格产生负面影响。一种帮助农民实现收获标准化的方法可能是通过使用CPH成熟的化学标记物和视觉指标。本研究分析了两个可可克隆品种ICS95和CCN51在成熟六、七、八个月时CPH的代谢分布。使用高效液相色谱-串联质谱（HPLC-MS/MS）进行非靶向代谢组学分析，以发现生物标志物并将其与可可成熟相关联。结果表明，与其他月份相比，第六个月存在强烈的代谢分化，且与品种无关。此外，在第七和第八个月，可可克隆品种之间也发现了代谢差异。我们注释了五个潜在的生化标记物，包括3-咖啡酰基天竺葵素5-葡萄糖苷、吲哚乙醛、原花青素A二聚体、原花青素C1和山奈酚。我们进一步研究了在相同成熟阶段，这些标记物的变化模式与CPH外观和质地的定量指标之间的相关性。我们还进行了功能分析，确定了三种可能的代谢途径：黄酮和黄酮醇生物合成、类黄酮生物合成以及色氨酸代谢，它们分别与胁迫感知、植物发育和防御相关。我们发现绿色密度与所有代谢物之间存在显著正相关。对于质地，与所有代谢物的相关性均为显著负相关。我们的结果表明，在哥伦比亚卡尔达斯地区，大约第六个月适合收获可可，以避免在成熟后期出现的所有影响可可豆质量的代谢变化。因此，研究可可成熟过程有助于估算最佳收获时间，并有助于收获实践的标准化。
