Spatial regulation of alpha-galactosidase activity and its influence on raffinose family oligosaccharides during seed maturation and germination in Cicer arietinum
Spatial regulation of alpha-galactosidase activity and its influence on raffinose family oligosaccharides during seed maturation and germination in Cicer arietinum
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DOI：
10.1080/15592324.2019.1709707
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发表时间：
2020-01-05
影响因子：
2.9
通讯作者：
Samuel, Marcus A.
中科院分区：
文献类型：
--
作者：
Arunraj, Rex;Skori, Logan;Samuel, Marcus A.
α -半乳糖苷或棉子糖家族寡糖（RFOs）富含豆类，被认为是引起肠胃胀气的抗营养因子。由于人类和其他单胃动物的胃中缺乏α -半乳糖苷酶，这些rfo不能被代谢，而是被肠道细菌处理，导致令人痛苦的肠胃胀气。在植物中，α (α)-半乳糖苷参与了种子成熟过程中的耐干燥性，并作为种子发芽时储存能量的来源。水解酶α -半乳糖苷酶（α -gal）可以将rfo分解成蔗糖和半乳糖，将单糖α -半乳糖释放回体内。通过表征成熟和发芽鹰嘴豆中的rfo、蔗糖、还原糖和α - gal活性，我们发现储存的rfo可能需要维持一个稳定的还原糖水平。这些还原糖可以很容易地转化为产生高能量萌发过程所需的能量。我们的观察结果表明，RFO水平在吸吸种子中最低，吸吸后迅速增加。rfo和α - gal活性可能都需要维持一个稳定的还原性单糖水平，从干燥的种子一直到萌发后，为增加萌发活力提供能量。
Alpha-galactosides or Raffinose Family Oligosaccharides (RFOs) are enriched in legumes and are considered as anti-nutritional factors responsible for inducing flatulence. Due to a lack of alpha-galactosidases in the stomachs of humans and other monogastric animals, these RFOs are not metabolized and are passed to the intestines to be processed by gut bacteria leading to distressing flatulence. In plants, alpha(alpha)-galactosides are involved in desiccation tolerance during seed maturation and act as a source of stored energy utilized by germinating seeds. The hydrolytic enzyme alpha-galactosidase (alpha-GAL) can break down RFOs into sucrose and galactose releasing the monosaccharide alpha-galactose back into the system. Through characterization of RFOs, sucrose, reducing sugars, and alpha-GAL activity in maturing and germinating chickpeas, we show that stored RFOs are likely required to maintain a steady-state level of reducing sugars. These reducing sugars can then be readily converted to generate energy required for the high energy-demanding germination process. Our observations indicate that RFO levels are lowest in imbibed seeds and rapidly increase post-imbibition. Both RFOs and the alpha-GAL activity are possibly required to maintain a steady-state level of the reducing monosaccharide sugars, starting from dry seeds all the way through post-germination, to provide the energy for increased germination vigor.