芸薹属栽培异源四倍体种形成初期的细胞学二倍体化及基因表达

Interspecific hybridization and allopolyploidization lead to the origin of many important crops. Synthetic Brassica has become one of the most widely used models to study the genetic and epigenetic alterations caused by meiosis in allopolyploids. In this project, resynthesized Brassica allotetraploids (B. juncea, AABB; B. napus, AACC) were produced from the reciprocal pair crosses of three Brassica diploids (B. rapa, genomes AA; B. nigra, BB; B. oleracea, CC) with different relatedness, and were investigated for successive generations for their variations in phenotype, cytological stability, gene expressions,DNA methylation and small RNAs. Then the effects of the different cytoplasm backgrounds and genome combinations on cytological diploidization and gene expressions were revealed, which gives new insights into the genetic mechanisms for the formation and evolution of Brassica allopolyploids. Additionally, many new kinds of allopolyploids were characterized for rapeseed breeding.

远缘杂交及异源多倍化导致许多重要作物的起源与进化, 而芸薹属栽培种成了研究作物异源多倍化的模式系统之一,特别是利用亲缘关系不同的三个二倍体种产生的芸薹属异源四倍体可以揭示核和细胞质基因组对异源多倍体遗传行为的影响。本项目将研究由三个芸薹属栽培二倍体种(白菜型油菜,甘蓝,黑芥）成对杂交合成的具有不同细胞质的芸苔属异源四倍体(甘蓝型和芥菜型油菜)在连续多世代的表型变化、细胞学行为变化、亲本染色体组的行为及稳定性、基因表达特征、DNA甲基化及小RNAs变化等,重点揭示芸薹属异源四倍体种在形成与进化初期的细胞学二倍体化过程、基因表达及调控机制,解析芸薹属异源多倍体形成与进化的遗传机理;同时，还为油菜遗传育种创造大量的新材料，因此具有重要的理论意义与应用价值。

远缘杂交及异源多倍化导致许多重要作物的起源与进化, 而芸薹属栽培种成了研究作物异源多倍化的模式系统之一,特别是利用亲缘关系不同的三个二倍体种产生的芸薹属异源四倍体可以揭示核和细胞质基因组对异源多倍体遗传行为的影响。本项目进行了由三个芸薹属栽培二倍体种(白菜型油菜,甘蓝,黑芥）成对杂交合成的5个异源四倍体（AACC/CCAA; BBCC/CCBB; AABB）的叶和角果的转录组测序及差异基因表达分析，研究了经过异源多倍化的A基因组及自然进化的A基因组对甘蓝型油菜基因表达的影响，分析了A/C基因组的不同剂量对杂种及多倍体（AC、AAC、CCA、CCAA）基因表达及互作的影响。观察了从三种杂交途径合成的芸薹属异源六倍体和后代的染色体配对及分离行为，揭示出染色体组的不同稳定性（B>A>C），B染色体组最稳定，C染色体组最不稳定。建立了甘蓝-黑芥附加系而分解了黑芥基因组，发现不同B基因组染色体的传递率存在明显差异、决定特定的表型。该研究为芸薹属异源多倍体形成与进化的遗传机理提供了新知识、为油菜遗传育种创造大量的新材料。