Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, College of Agronomy, Ministry of Education, Jiangxi Agricultural University, Nanchang, 330045, China.
Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, College of Agronomy, Ministry of Education, Jiangxi Agricultural University, Nanchang, 330045, China.
Plant Physiol Biochem. 2022 May 1;178:125-136. doi: 10.1016/j.plaphy.2022.02.022. Epub 2022 Mar 10.
Carbohydrates remobilization in non-leaf organs has a potential association with the formation of cotton yield. However, our understanding of the physiological and molecular mechanisms regulating carbon remobilization during flowering is still limited. The objectives of the study were to: i) evaluate the potential of carbohydrate remobilization in stems and roots to yield formation; ii) unravel the carbon metabolism and transport associated gene expression patterns regulating carbon remobilization. Two cotton lines 4003-6 and 4003-10 were employed to examine leaf photosynthesis, reproductive biomass accumulation, and carbon dynamics in stems and roots during reproductive growth. The results showed that decreasing leaf photosynthetic capacity combined with rapidly increasing reproductive biomass and leaf area index is accompanied by the initiation of carbohydrate remobilization during first flowering to peak flowering. The proportion of sucrose to total nonstructural carbohydrate was also decreased at that period. The upper and lower of stem recorded higher soluble sugars and starch concentrations, respectively compared to the two others. The gross contribution rate of carbon remobilization to seed cotton yield ranged from 2.83% to 7.12%. Key genes and sugar transporters related to starch and sucrose metabolism in the lower stem exhibited significant up- or down-regulated expressions indicating their important roles in carbon reserves remobilization. Three pivotal sugar transporters SWEET1, TMT2, and ERLD5 presented higher transcript levels at peak flowering suggesting more active sugar movement occurring at that stage. The present study provides potential target genes for engineering carbohydrate metabolism and transport to improve the remobilization efficiency of nonstructural carbohydrates.
碳水化合物在非叶器官中的再转移与棉花产量的形成有潜在的关联。然而，我们对调节开花期间碳再转移的生理和分子机制的理解仍然有限。本研究的目的是：i）评估茎和根中碳水化合物再转移对产量形成的潜力；ii）阐明与碳再转移相关的碳代谢和运输相关基因表达模式。使用两个棉花品系 4003-6 和 4003-10 来检查生殖生长期间叶片光合作用、生殖生物量积累和茎和根中的碳动态。结果表明，叶片光合能力的降低与生殖生物量和叶面积指数的迅速增加相结合，伴随着开花初期到盛花期碳水化合物再转移的开始。在此期间，蔗糖与总非结构性碳水化合物的比例也降低。与其他两个相比，茎的上部和下部记录到更高的可溶性糖和淀粉浓度。碳再转移对皮棉产量的总贡献率在 2.83%至 7.12%之间。与淀粉和蔗糖代谢相关的关键基因和糖转运蛋白在下茎中表现出明显的上调或下调表达，表明它们在碳储备再转移中起着重要作用。三个关键的糖转运蛋白 SWEET1、TMT2 和 ERLD5 在盛花期的转录水平较高，表明在此阶段发生了更活跃的糖移动。本研究为工程碳水化合物代谢和运输提供了潜在的目标基因，以提高非结构性碳水化合物的再转移效率。
