Variation in genome size, cell and nucleus volume, chromosome number and rDNA loci among duckweeds
Variation in genome size, cell and nucleus volume, chromosome number and rDNA loci among duckweeds
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DOI：
10.1038/s41598-019-39332-w
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发表时间：
2019-03-01
影响因子：
4.6
通讯作者：
Schubert, Ingo
中科院分区：
文献类型：
--
作者：
Hoang, Phuong T. N.;Schubert, Veit;Schubert, Ingo
浮萍是一种小型的、自由漂浮的、主要是无性的、高度幼态的生物。它们在开花植物中生长最快，在水产养殖和基因组生物学中越来越受到关注。基因组和染色体数据仍然很少。应用流式细胞仪的基因组大小测量，显微镜下测定叶片，细胞和细胞核形态，以及荧光原位杂交（FISH）定位的核糖体DNA（rDNA），我们比较了11种，代表五个浮萍属，以寻找潜在的相关性基因组大小，细胞和细胞核体积，简化的身体结构（幼态持续），染色体数目和rDNA位点。我们发现一个类似的14倍的基因组大小的变化（从160至2203 Mbp），相当大的差异，在叶片的大小和形状，高度可变的保卫细胞和核的大小，染色体数目（从2n = 36至82）和数量的5S和45S rDNA位点。一般来说，基因组大小与保卫细胞和核体积（p < 0.001）和幼态持续水平呈正相关，与叶片大小呈负相关。在个别情况下，这些相关性可能会被模糊，例如，特定的身体和细胞结构似乎与特定的漂浮风格有关。供试种间的染色体数目和rDNA位点变异与基因组大小无关。我们不能证实以前报道的种内变异的染色体数目之间的个别克隆属螺和Landoltia。
Duckweeds are small, free-floating, largely asexual and highly neotenous organisms. They display the most rapid growth among flowering plants and are of growing interest in aquaculture and genome biology. Genomic and chromosomal data are still rare. Applying flow-cytometric genome size measurement, microscopic determination of frond, cell and nucleus morphology, as well as fluorescence in situ hybridization (FISH) for localization of ribosomal DNA (rDNA), we compared eleven species, representative for the five duckweed genera to search for potential correlations between genome size, cell and nuclei volume, simplified body architecture (neoteny), chromosome numbers and rDNA loci. We found a similar to 14-fold genome size variation (from 160 to 2203 Mbp), considerable differences in frond size and shape, highly variable guard cell and nucleus size, chromosome number (from 2n = 36 to 82) and number of 5S and 45S rDNA loci. In general, genome size is positively correlated with guard cell and nucleus volume (p < 0.001) and with the neoteny level and inversely with the frond size. In individual cases these correlations could be blurred for instance by particular body and cell structures which seem to be linked to specific floating styles. Chromosome number and rDNA loci variation between the tested species was independent of the genome size. We could not confirm previously reported intraspecific variation of chromosome numbers between individual clones of the genera Spirodela and Landoltia.