Recombination within the apospory specific genomic region leads to the uncoupling of apomixis components in Cenchrus ciliaris
Recombination within the apospory specific genomic region leads to the uncoupling of apomixis components in Cenchrus ciliaris
复制标题
DOI：
10.1007/s00425-013-1873-5
复制
发表时间：
2013-07-01
期刊：
影响因子：
4.3
通讯作者：
Ozias-Akins, Peggy
中科院分区：
文献类型：
--
作者：
Conner, Joann A.;Gunawan, Gunawati;Ozias-Akins, Peggy
无融合生殖使母体基因型通过种子进行克隆繁殖。如果可以通过基因工程或基因渗入来利用无融合生殖，它将对农作物产生重大的经济影响。在禾本科植物Pennisetum squamulatum和Cenchrus ciliaris（syn.在纤毛类无融合生殖中，无融合生殖受单个显性“基因座”控制，即无孢子体特异性基因组区域（ASGR）。对于鳞叶假单胞菌，已经鉴定出18个已发表的测序特征扩增区（SCAR）标记，它们总是与无孢子生殖共分离。这些标记中有6个在近缘种C. ciliaris与该性状共分离。对有性生殖与无融合生殖的C. ciliaris基因型鉴定了一株A8，保留了六个ASGR连锁的SCAR标记中的两个。产生了额外的和新鉴定的ASGR连锁标记，以帮助鉴定ASGR内重组的程度。基于缺失标记的分析，A8重组植物已经丢失了ASGR的显著部分，但继续形成无孢子胚囊。从无孢子胚囊产生的幼苗是6倍性水平，因此A8重组体不表达孤雌生殖。重组A8植物在降低ASGR基因座的复杂性以确定无孢子胚囊形成所需的因子方面向前迈进了一步，并记录了C.纤毛
Apomixis enables the clonal propagation of maternal genotypes through seed. If apomixis could be harnessed via genetic engineering or introgression, it would have a major economic impact for agricultural crops. In the grass species Pennisetum squamulatum and Cenchrus ciliaris (syn. P. ciliare), apomixis is controlled by a single dominant "locus", the apospory-specific genomic region (ASGR). For P. squamulatum, 18 published sequenced characterized amplified region (SCAR) markers have been identified which always co-segregate with apospory. Six of these markers are conserved SCARs in the closely related species, C. ciliaris and co-segregate with the trait. A screen of progeny from a cross of sexual x apomictic C. ciliaris genotypes identified a plant, A8, retaining two of the six ASGR-linked SCAR markers. Additional and newly identified ASGR-linked markers were generated to help identify the extent of recombination within the ASGR. Based on analysis of missing markers, the A8 recombinant plant has lost a significant portion of the ASGR but continues to form aposporous embryo sacs. Seedlings produced from aposporous embryo sacs are 6x in ploidy level and hence the A8 recombinant does not express parthenogenesis. The recombinant A8 plant represents a step forward in reducing the complexity of the ASGR locus to determine the factor(s) required for aposporous embryo sac formation and documents the separation of expression of the two components of apomixis in C. ciliaris.