Central South University of Forestry and Technology, Changsha, Hunan, 410000, China.
School of Economics, Qingdao University, Qingdao, Shandong, 266100, China.
J Plant Physiol. 2023 Mar;282:153918. doi: 10.1016/j.jplph.2023.153918. Epub 2023 Jan 18.
The chestnuts of Castanea mollissima Bl. are an important food crop in China, and have high nutritional content. To understand the pattern of sugar accumulation during chestnut nut development, the related enzyme gene regulatory pathways, and the molecular regulatory mechanisms of chestnut sugar biosynthesis metabolism, two chestnut varieties with different sugar content, namely Chengbu Youzhu (hereinafter referred to as CBYZ) and AnYou No. 1 (hereinafter referred to as AY01), were selected for investigation. Total sugar and starch content, and the activity of enzymes related to sugar accumulation, were measured in the nuts of the two chestnut varieties 10 days after flowering (DAF), 20 DAF, 30 DAF, 40 DAF, 50 DAF, 60 DAF, 70 DAF, 80 DAF, and 90 DAF. Changes in starch, straight-chain starch, and branched-chain starch content, and sucrose-phosphate synthase, soluble starch synthase, and granule-bound starch synthase enzyme activities were consistent with one-another. A total of 24 differentially expressed genes between the two varieties were associated with sugar biosynthesis and metabolism at three key stages (30, 60, and 90 DAF) of sugar accumulation. Further analysis showing upregulation of the expression of starch-related genes, such as β-amylase, GYS, and INV indicated that these genes were not actively expressed in AY01, resulting in slow accumulation of starch and reduced sugar content. By contrast, the downregulation of the expression of genes, such as PGK and MDH1, indicated that these genes were actively expressed in low-sugar chestnuts, resulting in the rapid fermentation of sugars. A link between gene up- or down-regulation during different developmental stages of chestnut and the effect of their expression on sugar content were established by KEGG pathway enrichment analysis. These findings provide further insights into the mechanism of sugar biosynthesis in chestnuts.
板栗是中国重要的木本粮食作物之一，具有较高的营养价值。为了阐明板栗坚果发育过程中糖积累的模式、相关酶基因调控途径以及板栗糖生物合成代谢的分子调控机制，本研究选择了两个糖含量不同的板栗品种（成武油栗，简称 CBYZ 和燕油 1 号，简称 AY01）进行研究。在授粉后 10 天（DAF）、20 DAF、30 DAF、40 DAF、50 DAF、60 DAF、70 DAF、80 DAF 和 90 DAF 时，测量了两个板栗品种坚果中的总糖和淀粉含量以及与糖积累相关的酶的活性。淀粉、直链淀粉和支链淀粉含量以及蔗糖磷酸合酶、可溶性淀粉合酶和颗粒结合淀粉合酶酶活性的变化是一致的。在糖积累的三个关键时期（30、60 和 90 DAF），共有 24 个差异表达基因与糖的生物合成和代谢有关。进一步的分析表明，淀粉相关基因（如β-淀粉酶、GYS 和 INV）的表达上调，表明这些基因在 AY01 中没有积极表达，导致淀粉积累缓慢，糖含量降低。相比之下，PGK 和 MDH1 等基因的表达下调表明，这些基因在低糖板栗中积极表达，导致糖的快速发酵。通过 KEGG 途径富集分析，建立了板栗不同发育阶段基因的上调或下调与基因表达对糖含量影响之间的联系。这些发现为板栗糖的生物合成机制提供了进一步的见解。
