辣椒杂交种与亲本苗期叶片基因差异表达分析

Differentially expressed gene profile of hot pepper seedling leaves between hybrid and its parental lines

目前辣椒杂种优势的利用已取得很大成效,但是辣椒杂种优势的分子机理仍然不明。辣椒杂种优势的分子机理是一个重要的生物学和农学课题。为比较分析苗期辣椒杂交种(D6×D7,D7×D6)及其亲本(D6、D7)的成熟功能叶转录谱,把4个功能叶c DNA文库在Illumina Hi Seq 2000平台进行RNASeq分析。通过转录组测序,共得到0.6亿条原始的reads,经过筛选获得0.44亿条高质量reads(100 bp)。基因存在与缺失变异统计结果表明,单亲表达一致型有1068个(6.20%)和780个(4.56%)基因分别在正交(D6×D7)和反交(D7×D6)中被检测到,在4种基因存在与缺失变异类型中所占比例比较高。对双亲表达量不同的基因作进一步表达模式分析,结果表明,杂种(正、反交)与双亲相比,大部分基因呈均非加性表达,加性表达基因比例不足8%,在非加性表达基因中,超显性表达的基因占大多数,正、反交分别为66.08%和62.96%,这与偏单亲的显性模型分析结论相一致。

In spite of the great success in utilizing heterosis in hot pepper （ Capsicum annuum L. ） breeding and production, the underlying molecular mechanisms are still not well-understood, which need to be resolved as they are important subjects in basic biology and agronomy. In this study, mature leaf transcriptomes from the F1 hybrids （ D6 × D7 and D7 × D6 ） and their parental lines （ D6× D7 ） were compared, cDNA libraries were prepared using the sixth true leaves on plants at seedlings followed by RNA-Seq on a Illumina HiSeq 2000 sequencer. RNA-Seq generated 0.6 billion raw reads, and 0.44 billion high-quality reads （ lO0bp ） were obtained after the filtering process. Statistical analysis of genes with presence/deletion variations showed that there are 1068 （ 6.20% ） and 780 （ 4.56% ） genes in the ＂single parent express consistent type＂ in the direct （ D6 × D7 ） and reciprocal （ D7 × D6 ） F1 hybrids, respectively. A large portion of the transcriotomes in the four pepper genotypes belong to this type of genes. Gene expression profiling analysis indicates that in F1 hybrids （ direct and reciprocal crosses ）, more genes fit into the non- additive expression type compared to the parents. Less than 8% of the genes belong to the the additive expression type. In the non-additive expression type, a large number of the genes fit into the epistatic dominance expression pattern ; it is 66.08% and 62.96% in direct and reciprocal F1 hybrids, respectively. The expression type of these genes fits into the partial single parent dominance type.