Zhang Qiang, Huang Jing, Zhou Peng, Hao Mingzhuo, Zhang Min
Co-Innovation Center for Sustainable Forestry in Southern China, College of Biology and the Environment, Nanjing Forestry University, 159 Longpan Road, Nanjing 210037, China.
Jiangsu Academy of Forestry, 109 Danyang Road, Dongshanqiao, Nanjing 211153, China.
Plants (Basel). 2021 Mar 15;10(3):552. doi: 10.3390/plants10030552.
'Belgica Aurea' is an attractive ornamental plant bearing yellow-green variegated leaves. However, the mechanisms underlying the formation of leaf variegation in this species are still unclear. Here, the juvenile yellow leaves and mature variegated leaves of 'Belgica Aurea' were compared in terms of leaf structure, pigment content and transcriptomics. The results showed that no obvious differences in histology were noticed between yellow and variegated leaves, however, ruptured thylakoid membranes and altered ultrastructure of chloroplasts were found in yellow leaves (yellow) and yellow sectors of the variegated leaves (variegation). Moreover, the yellow leaves and the yellow sectors of variegated leaves had significantly lower chlorophyll compared to green sectors of the variegated leaves (green). In addition, transcriptomic sequencing identified 1675 differentially expressed genes (DEGs) among the three pairwise comparisons (yellow vs. green, variegation vs. green, yellow vs. variegation). Expression of magnesium-protoporphyrin IX monomethyl ester (MgPME) [oxidative] cyclase, monogalactosyldiacylglycerol (MGDG) synthase and digalactosyldiacylglycerol (DGDG) synthase were decreased in the yellow leaves. Altogether, chlorophyll deficiency might be the main factors driving the formation of leaf variegation in 'Belgica Aurea'.
“金叶比利时菊”是一种颇具吸引力的观赏植物，其叶片具有黄绿相间的斑纹。然而，该物种叶片斑纹形成的潜在机制仍不清楚。在此，对“金叶比利时菊”的幼嫩黄叶和成熟斑纹叶在叶片结构、色素含量和转录组学方面进行了比较。结果表明，黄叶和斑纹叶在组织学上未发现明显差异，然而，在黄叶（黄色）和斑纹叶的黄色部分（斑纹）中发现了类囊体膜破裂和叶绿体超微结构改变的情况。此外，与斑纹叶的绿色部分（绿色）相比，黄叶和斑纹叶的黄色部分叶绿素含量显著较低。另外，转录组测序在三个两两比较（黄色与绿色、斑纹与绿色、黄色与斑纹）中鉴定出1675个差异表达基因（DEG）。黄叶中镁原卟啉IX单甲酯（MgPME）[氧化]环化酶、单半乳糖基二酰基甘油（MGDG）合酶和二半乳糖基二酰基甘油（DGDG）合酶的表达降低。总之，叶绿素缺乏可能是驱动“金叶比利时菊”叶片斑纹形成的主要因素。
