Stupar Robert M, Bhaskar Pudota B, Yandell Brian S, Rensink Willem A, Hart Amy L, Ouyang Shu, Veilleux Richard E, Busse James S, Erhardt Robert J, Buell C Robin, Jiang Jiming
Department of Horticulture, University of Wisconsin, Madison, WI 53706, USA.
Genetics. 2007 Aug;176(4):2055-67. doi: 10.1534/genetics.107.074286. Epub 2007 Jun 11.
Polyploidy is remarkably common in the plant kingdom and polyploidization is a major driving force for plant genome evolution. Polyploids may contain genomes from different parental species (allopolyploidy) or include multiple sets of the same genome (autopolyploidy). Genetic and epigenetic changes associated with allopolyploidization have been a major research subject in recent years. However, we know little about the genetic impact imposed by autopolyploidization. We developed a synthetic autopolyploid series in potato (Solanum phureja) that includes one monoploid (1x) clone, two diploid (2x) clones, and one tetraploid (4x) clone. Cell size and organ thickness were positively correlated with the ploidy level. However, the 2x plants were generally the most vigorous and the 1x plants exhibited less vigor compared to the 2x and 4x individuals. We analyzed the transcriptomic variation associated with this autopolyploid series using a potato cDNA microarray containing approximately 9000 genes. Statistically significant expression changes were observed among the ploidies for approximately 10% of the genes in both leaflet and root tip tissues. However, most changes were associated with the monoploid and were within the twofold level. Thus, alteration of ploidy caused subtle expression changes of a substantial percentage of genes in the potato genome. We demonstrated that there are few genes, if any, whose expression is linearly correlated with the ploidy and can be dramatically changed because of ploidy alteration.
多倍体现象在植物界极为常见，多倍体化是植物基因组进化的主要驱动力。多倍体可能包含来自不同亲本物种的基因组（异源多倍体），或者包含同一基因组的多套拷贝（同源多倍体）。近年来，与异源多倍体化相关的遗传和表观遗传变化一直是主要研究课题。然而，我们对同源多倍体化所产生的遗传影响知之甚少。我们培育了一个马铃薯（Solanum phureja）的人工合成同源多倍体系，其中包括一个单倍体（1x）克隆、两个二倍体（2x）克隆和一个四倍体（4x）克隆。细胞大小和器官厚度与倍性水平呈正相关。然而，与二倍体和四倍体植株相比，二倍体植株通常最为健壮，而单倍体植株活力较弱。我们使用一个包含约9000个基因的马铃薯cDNA微阵列，分析了与该同源多倍体系相关的转录组变异。在小叶和根尖组织中，约10%的基因在不同倍性之间观察到了具有统计学意义的表达变化。然而，大多数变化与单倍体相关，且变化幅度在两倍以内。因此，倍性改变导致了马铃薯基因组中相当比例的基因发生微妙的表达变化。我们证明，几乎没有基因（如果有的话）的表达与倍性呈线性相关，并且不会因倍性改变而发生显著变化。
