近日,，國際著名雜志PLoS One在線刊登了西北農(nóng)林科技大學(xué)園藝學(xué)院和澳大利亞澳洲大學(xué)的研究人員展開合作的最新研究成果“Molecular genetic features of polyploidization and aneuploidization reveal unique patterns for genome duplication in diploid Malus,，”文章中，作者揭示了在蘋果屬植物多倍體化遺傳與進(jìn)化機(jī)制研究方面取得的重要進(jìn)展,。
西北農(nóng)林科技大學(xué)園藝學(xué)院的萬怡震教授和韓明玉教授為這篇文章的共同通訊作者,。前者的主要研究方向?yàn)樘O果品質(zhì)性狀基因的分子遺傳定位，抗早期落葉病基因的克隆和功能,，蘋果砧木資源評(píng)價(jià),、利用及育種研究。韓明玉教授則主要從事果樹遺傳育種與栽培生理等研究,。
眾所周知,，多倍體化是生物基因組加倍的主要方式，也是物種進(jìn)化的重要途徑,。但是,，人們對整個(gè)植物界的非整倍體化分子機(jī)制仍不十分清楚。該研究建立在大量試驗(yàn)數(shù)據(jù)基礎(chǔ)上,，利用細(xì)胞生物學(xué)和分子生物學(xué)手段,，闡述了二倍體蘋果親本雜交后代整倍體化及非整倍化特性。研究表明,，蘋果二倍體雜交后代非整體個(gè)數(shù)超過整多倍體個(gè)數(shù),，說明非整倍體化可能是蘋果植物基因組加倍的主要方式。研究證明所有多倍體化的配子都是遺傳雜合性的,，說明減數(shù)分裂中第一分裂出現(xiàn)異常是導(dǎo)致配子基因組加倍的唯一原因,。
該研究首次利用分子生物學(xué)提供可靠論據(jù)表明,，多倍體因其遺傳上更高的雜合性而表現(xiàn)出更好的適應(yīng)能力。本文也提供了利用共顯性分子標(biāo)記加速三倍體蘋果育種進(jìn)程的思路,，提出了如何獲得奇數(shù)基礎(chǔ)染色體新物種的可能進(jìn)化機(jī)制,，并對蘋果屬植物起源進(jìn)化模式進(jìn)行了較大的修訂和完善。文中還對非整倍體化在物種進(jìn)化方面的重要性及非整倍體植物在遺傳育種上的應(yīng)用前景進(jìn)行了系統(tǒng)分析與評(píng)價(jià),。該研究成果極大地有助于我們對蘋果屬植物進(jìn)化,、物種形成和適應(yīng)性的理解，也為人們研究其他物種多倍體化機(jī)制提供了方法與思路,。（生物谷Bioon.com）
doi:10.1371/journal.pone.0029449
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Molecular Genetic Features of Polyploidization and Aneuploidization Reveal Unique Patterns for Genome Duplication in Diploid Malus
Michael J. Considine2,3, Yizhen Wan1*, Mario F. D'Antuono3, Qian Zhou1, Mingyu Han1*, Hua Gao1, Man Wang1
Polyploidization results in genome duplication and is an important step in evolution and speciation. The Malus genome confirmed that this genus was derived through auto-polyploidization, yet the genetic and meiotic mechanisms for polyploidization, particularly for aneuploidization, are unclear in this genus or other woody perennials. In fact the contribution of aneuploidization remains poorly understood throughout Plantae. We add to this knowledge by characterization of eupolyploidization and aneuploidization in 27,542 F1 seedlings from seven diploid Malus populations using cytology and microsatellite markers. We provide the first evidence that aneuploidy exceeds eupolyploidy in the diploid crosses, suggesting aneuploidization is a leading cause of genome duplication. Gametes from diploid Malus had a unique combinational pattern; ova preserved euploidy exclusively, while spermatozoa presented both euploidy and aneuploidy. All non-reduced gametes were genetically heterozygous, indicating first-division restitution was the exclusive mode for Malus eupolyploidization and aneuploidization. Chromosome segregation pattern among aneuploids was non-uniform, however, certain chromosomes were associated for aneuploidization. This study is the first to provide molecular evidence for the contribution of heterozygous non-reduced gametes to fitness in polyploids and aneuploids. Aneuploidization can increase, while eupolyploidization may decrease genetic diversity in their newly established populations. Auto-triploidization is important for speciation in the extant Malus. The features of Malus polyploidization confer genetic stability and diversity, and present heterozygosity, heterosis and adaptability for evolutionary selection. A protocol using co-dominant markers was proposed for accelerating apple triploid breeding program. A path was postulated for evolution of numerically odd basic chromosomes. The model for Malus derivation was considerably revised. Impacts of aneuploidization on speciation and evolution, and potential applications of aneuploids and polyploids in breeding and genetics for other species were evaluated in depth. This study greatly improves our understanding of evolution, speciation, and adaptation of the Malus genus, and provides strategies to exploit polyploidization in other species.
