Martin Guillaume, Carreel Françoise, Coriton Olivier, Hervouet Catherine, Cardi Céline, Derouault Paco, Roques Danièle, Salmon Frédéric, Rouard Mathieu, Sardos Julie, Labadie Karine, Baurens Franc-Christophe, D'Hont Angélique
CIRAD, UMR AGAP, Montpellier, France.
INRA, UMR APBV, Le Rheu, France.
Mol Biol Evol. 2017 Sep 1;34(9):2140-2152. doi: 10.1093/molbev/msx164.
Most banana cultivars are triploid seedless parthenocarpic clones derived from hybridization between Musa acuminata subspecies and sometimes M. balbisiana. M. acuminata subspecies were suggested to differ by a few large chromosomal rearrangements based on chromosome pairing configurations in intersubspecies hybrids. We searched for large chromosomal rearrangements in a seedy M. acuminata ssp. malaccensis banana accession through mate-pair sequencing, BAC-FISH, targeted PCR and marker (DArTseq) segregation in its progeny. We identified a heterozygous reciprocal translocation involving two distal 3 and 10 Mb segments from chromosomes 01 and 04, respectively, and showed that it generated high segregation distortion, reduced recombination and linkage between chromosomes 01 and 04 in its progeny. The two chromosome structures were found to be mutually exclusive in gametes and the rearranged structure was preferentially transmitted to the progeny. The rearranged chromosome structure was frequently found in triploid cultivars but present only in wild malaccensis ssp. accessions, thus suggesting that this rearrangement occurred in M. acuminata ssp. malaccensis. We propose a mechanism for the spread of this rearrangement in Musa diversity and suggest that this rearrangement could have played a role in the emergence of triploid cultivars.
大多数香蕉品种是三倍体无籽单性结实克隆体，源自尖叶蕉亚种之间的杂交，有时还涉及野蕉。基于亚种间杂交中的染色体配对构型，有研究表明尖叶蕉亚种存在一些大规模的染色体重排。我们通过配对末端测序、细菌人工染色体荧光原位杂交（BAC-FISH）、靶向聚合酶链式反应（PCR）以及其后代中的标记（多样性阵列技术测序，DArTseq）分离，在一个有籽的尖叶蕉亚种马六甲蕉香蕉种质中寻找大规模染色体重排。我们鉴定出一个杂合的相互易位，分别涉及来自1号和4号染色体的两个远端3兆碱基和10兆碱基片段，并表明它在其后代中产生了高度的分离畸变，减少了1号和4号染色体之间的重组和连锁。发现这两种染色体结构在配子中相互排斥，并且重排结构优先传递给后代。重排的染色体结构在三倍体品种中经常出现，但仅存在于野生马六甲蕉亚种种质中，因此表明这种重排在尖叶蕉亚种马六甲蕉中发生。我们提出了这种重排在香蕉多样性中传播的机制，并表明这种重排可能在三倍体品种的出现中发挥了作用。
