Harvesting at different time-points of day affects glucosinolate metabolism during postharvest storage of broccoli
Harvesting at different time-points of day affects glucosinolate metabolism during postharvest storage of broccoli
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DOI：
10.1016/j.foodres.2020.109529
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发表时间：
2020-10-01
影响因子：
8.1
通讯作者：
Martinez, Gustavo
中科院分区：
文献类型：
--
作者：
Casajus, Victoria;Demkura, Patricia;Martinez, Gustavo
西兰花的消费为人类饮食提供了大量具有营养特性的化合物。西兰花含有高含量的硫代葡萄糖苷，这是一种具有抗癌活性的特殊代谢化合物。在以前的工作中，我们发现，收获不同的时间点在白天影响西兰花头在采后储存衰老的速度。在这项工作中，我们测试了相同的文化实践，以评估硫代葡萄糖甙含量和参与硫代葡萄糖甙代谢的基因表达。在8：00、13：00和18：00 h收获西兰花头，并在20 ℃下避光储存5 d。我们发现硫甙池的含量和组成受收获时间的影响。吲哚硫代葡萄糖苷的水平随着当天收获的时间而下降，而吲哚硫代葡萄糖苷仅显示出适度的下降。与脂肪族芥子油苷生物合成相关的基因的表达在白天是可变的。在吲哚类芥子油苷方面，转录因子BolMYB 51在13：00 h左右表达增加，这与其生物合成相关基因的表达增加密切相关。在采后期间，脂肪酸的含量下降，与其生物合成相关的基因的表达也下降。相反，在吲哚类化合物的情况下，它们的含量保持不变或略有变化，而相关的生物合成基因的表达仅略有下降。最后，硫代葡萄糖苷的降解相关的基因出现强烈的调控光条件下，因为他们的表达增加，在白天和减少显着在采后贮藏在黑暗中。这些结果表明，收获西兰花接近中午将方便保持较高水平的硫代葡萄糖苷在采后贮藏。
The consumption of broccoli provides a large quantity of compounds with nutraceutical properties to the human diet. Broccoli has a high content of glucosinolates, compounds of the specialized metabolism with anticarcinogenic activity. In a previous work, we found that harvesting different time-points during the day affects the rate of senescence of broccoli heads during postharvest storage. In this work, we tested the same cultural practice to evaluate glucosinolate content and expression of genes involved in glucosinolate metabolism. Broccoli heads were harvested at 8:00, 13:00 and 18:00 h and stored for 5 d at 20 degrees C in darkness. We found that content and composition of the glucosinolate pool was affected by the time of harvest. Levels of indolic glucosinolates decreased with the time of harvest on the day whereas indolic glucosinolate showed only a moderate decrease. The expression of genes associated to the biosynthesis of aliphatic glucosinolates was variable during the day. In relation to indolic glucosinolates, an increase in the expression of the transcription factor BolMYB51 was detected around 13:00 h, which strongly correlated with the increase in expression of genes associated to their biosynthesis towards the end of the day.During postharvest, the storage in darkness affected differently the metabolisms of indolic and aliphatic glucosinolates. The content of aliphatics decreased during the postharvest period, as well as the expression of the genes associated with their biosynthesis. In contrast, in the case of indolics, their content remained constant or varied slightly, while the expression of the associated biosynthetic genes decreased only slightly. Finally, the genes related to the degradation of glucosinolates appeared to be strongly regulated by light conditions, since their expression increased during the course of the day and decreased markedly during postharvest storage in darkness.These results suggest that harvesting of broccolis close to noon would be convenient to maintain higher levels of glucosinolates during postharvest storage.