小柯机器人

荷兰瓦格宁根大学Peter J. van Dijk、M. Eric Schranz等研究人员合作发现，来自无融合生殖蒲公英的一个基因可以诱导莴苣中的卵细胞分裂而不受精。相关论文于2022年1月6日在线发表在《自然—遗传学》杂志上。

研究人员从无融合生殖的蒲公英中分离出了PARTHENOGENESIS（PAR）基因，该基因在未受精的卵细胞中引发胚胎发育。PAR编码一个K2-2锌指、EAR结构的蛋白质。与隐性性状等位基因不同，显性PAR等位基因在卵细胞中表达，并且在启动子中插入了一个微型倒置重复可转座元件（MITE）。含有MITE的启动子可以调用有性莴苣的同源基因，以补充蒲公英LOSS OF PARTHENOGENESIS突变体。

一个类似的MITE也存在于鹰嘴豆PAR基因的启动子中，这表明了一个平行进化的案例。蒲公英PAR在莴苣卵细胞中的异源表达，在没有受精的情况下诱导出单倍体胚胎样结构。有性的PAR等位基因在花粉中表达，表明在有性的物种中，基因产物在受精后释放出对胚胎发生的阻断，而在无性的物种中，PAR的表达在没有受精的情况下触发胚胎发生。

据悉，无融合生殖，即种子的克隆形成，是开花植物中一种罕见但广泛分布的性状。

附：英文原文

Title: A PARTHENOGENESIS allele from apomictic dandelion can induce egg cell division without fertilization in lettuce

Author: Underwood, Charles J., Vijverberg, Kitty, Rigola, Diana, Okamoto, Shunsuke, Oplaat, Carla, Camp, Rik H. M. Op den, Radoeva, Tatyana, Schauer, Stephen E., Fierens, Joke, Jansen, Kim, Mansveld, Sandra, Busscher, Marco, Xiong, Wei, Datema, Erwin, Nijbroek, Koen, Blom, Evert-Jan, Bicknell, Ross, Catanach, Andrew, Erasmuson, Sylvia, Winefield, Christopher, van Tunen, Arjen J., Prins, Marcel, Schranz, M. Eric, van Dijk, Peter J.

Issue&Volume: 2022-01-06

Abstract: Apomixis, the clonal formation of seeds, is a rare yet widely distributed trait in flowering plants. We have isolated the PARTHENOGENESIS (PAR) gene from apomictic dandelion that triggers embryo development in unfertilized egg cells. PAR encodes a K2-2 zinc finger, EAR-domain protein. Unlike the recessive sexual alleles, the dominant PAR allele is expressed in egg cells and has a miniature inverted-repeat transposable element (MITE) transposon insertion in the promoter. The MITE-containing promoter can invoke a homologous gene from sexual lettuce to complement dandelion LOSS OF PARTHENOGENESIS mutants. A similar MITE is also present in the promoter of the PAR gene in apomictic forms of hawkweed, suggesting a case of parallel evolution. Heterologous expression of dandelion PAR in lettuce egg cells induced haploid embryo-like structures in the absence of fertilization. Sexual PAR alleles are expressed in pollen, suggesting that the gene product releases a block on embryogenesis after fertilization in sexual species while in apomictic species PAR expression triggers embryogenesis in the absence of fertilization. The PARTHENOGENESIS (PAR) gene is identified in apomictic dandelion. A dominant allele has a MITE transposon insertion similar to that found in apomictic hawkweed. Expression of dandelion PAR in lettuce induces embryo-like structures without fertilization.

DOI: 10.1038/s41588-021-00984-y

Source: https://www.nature.com/articles/s41588-021-00984-y

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