Institute of Food Crops, Hubei Academy of Agricultural Sciences, Wuhan 430064, China.
Agricultural College, Yangtze University, Jingzhou 434022, China.
Genes (Basel). 2023 Nov 22;14(12):2112. doi: 10.3390/genes14122112.
Leafy sweet potato is a new type of sweet potato, whose leaves and stems are used as green vegetables. However, sweet potato tips can be affected by pre-harvest factors, especially the intensity of light. At present, intercropping, greenhouse planting, and photovoltaic agriculture have become common planting modes for sweet potato. Likewise, they can also cause insufficient light conditions or even low light stress. This research aimed to evaluate the influence of four different shading levels (no shading, 30%, 50%, and 70% shading degree) on the growth profile of sweet potato leaves. The net photosynthetic rate, chlorophyll pigments, carbohydrates, and polyphenol components were determined. Our findings displayed that shading reduced the content of the soluble sugar, starch, and sucrose of leaves, as well as the yield and Pn. The concentrations of Chl a, Chl b, and total Chl were increased and the Chl a/b ratio was decreased for the more efficient interception and absorption of light under shading conditions. In addition, 30% and 50% shading increased the total phenolic, total flavonoids, and chlorogenic acid. Transcriptome analysis indicated that genes related to the antioxidant, secondary metabolism of phenols and flavonoids, photosynthesis, and MAPK signaling pathway were altered in response to shading stresses. We concluded that 30% shading induced a high expression of antioxidant genes, while genes related to the secondary metabolism of phenols and flavonoids were upregulated by 50% shading. And the MAPK signaling pathway was modulated under 70% shading, and most stress-related genes were downregulated. Moreover, the genes involved in photosynthesis, such as chloroplast development, introns splicing, and Chlorophyll synthesis, were upregulated as shading levels increased. This research provides a new theoretical basis for understanding the tolerance and adaptation mechanism of leafy sweet potato in low light environments.
叶用甘薯是一种新型甘薯，其叶片和茎可作为绿色蔬菜食用。然而，甘薯梢端可能会受到采前因素的影响，特别是光照强度。目前，甘薯的间作、温室种植和光伏农业已成为常见的种植模式。同样，这些种植模式也会导致光照条件不足，甚至出现低光照胁迫。本研究旨在评估四种不同遮荫程度（无遮荫、30%遮荫、50%遮荫和 70%遮荫）对甘薯叶片生长特性的影响。测定了叶片的净光合速率、叶绿素色素、碳水化合物和多酚成分。研究结果表明，遮荫降低了叶片中可溶性糖、淀粉和蔗糖的含量，以及产量和 Pn。Chl a、Chl b 和总 Chl 的浓度增加，Chl a/b 比值降低，这表明在遮荫条件下，叶片对光的更有效吸收和截获。此外，30%和 50%的遮荫增加了总酚、总类黄酮和绿原酸的含量。转录组分析表明，与抗氧化、酚类和类黄酮的次生代谢、光合作用和 MAPK 信号通路相关的基因在应对遮荫胁迫时发生了变化。我们得出结论，30%的遮荫诱导了抗氧化基因的高表达，而 50%的遮荫则上调了与酚类和类黄酮的次生代谢相关的基因。此外，MAPK 信号通路在 70%遮荫下被调节，大多数与胁迫相关的基因被下调。而且，与光合作用相关的基因，如叶绿体发育、内含子剪接和叶绿素合成，随着遮荫程度的增加而上调。本研究为深入了解叶用甘薯在低光照环境下的耐受和适应机制提供了新的理论依据。
