Zykin Pavel A, Andreeva Elena A, Tsvetkova Natalia V, Bulanov Andrey N, Voylokov Anatoly V
Faculty of Biology, St. Petersburg State University, Universiteskaya nab. 7/9, St. Petersburg 199034, Russia.
Laboratory of Plant Genetics and Biotechnology, Vavilov Institute of General Genetics Russian Academy of Sciences, Gubkina st. 3, Moscow 119991, Russia.
Plants (Basel). 2025 Aug 17;14(16):2557. doi: 10.3390/plants14162557.
Rye exhibits high diversity in grain coloration among small cereals, which is mainly linked to the presence of colored flavonoids synthesized in the outer layers of the kernel. This variability is not yet sufficiently described from colorimetric, cytological, and biochemical points of view. In this study, the localization of flavonoid pigments, anthocyanins and proanthocyanidins (PAs), was analyzed across different grain tissues in 26 rye lines with identified anthocyanin grain color genes. Grain coloration was objectively characterized using the CIELAB color coordinates and the GrainScan software for image analysis of individual grains. The distribution of anthocyanins and PAs was investigated through light microscopy and matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) on longitudinal and cross sections of the grains. The results revealed that violet-grained lines accumulate anthocyanins in the pericarp, while green-grained lines contain anthocyanins in the aleurone layer. MALDI-IMS confirmed the presence of specific anthocyanins: cyanidins in the pericarp of violet-grained lines and delphinidins in the aleurone layer of green-grained lines. All studied lines, except for the anthocyanin-less vi3 mutants, exhibited PAs in the brown-colored testa. Four main color groups of the rye grains (yellow, green, brown, and violet) could be clearly differentiated using the CIE color coordinate h°.
黑麦在小粒谷物中籽粒颜色表现出高度多样性，这主要与籽粒外层合成的有色黄酮类化合物的存在有关。从比色法、细胞学和生物化学角度来看，这种变异性尚未得到充分描述。在本研究中，对26个具有已鉴定花青素籽粒颜色基因的黑麦品系不同籽粒组织中的类黄酮色素、花青素和原花青素（PAs）进行了定位分析。使用CIELAB颜色坐标和GrainScan软件对单个籽粒进行图像分析，客观地表征了籽粒颜色。通过光学显微镜和基质辅助激光解吸/电离成像质谱（MALDI-IMS）对籽粒的纵切面和横切面进行研究，调查了花青素和PAs的分布。结果表明，紫色籽粒品系在果皮中积累花青素，而绿色籽粒品系在糊粉层中含有花青素。MALDI-IMS证实了特定花青素的存在：紫色籽粒品系果皮中的矢车菊素和绿色籽粒品系糊粉层中的飞燕草素。除了无花青素的vi3突变体之外，所有研究的品系在棕色种皮中均表现出PAs。使用CIE颜色坐标h°可以清楚地区分黑麦籽粒的四个主要颜色组（黄色、绿色、棕色和紫色）。
