桃是世界上分布最广泛的栽培果树之一，位居落叶果树前3位，其鲜果食用、果汁和罐头加工制品一直深受消费者喜爱。随着社会对其果实和相关制品需求量的进一步增加，如何高效快速地培育优良桃品种是目前产业发展的瓶颈。因此，开展桃的功能基因组学研究，无疑有助于促进育种和产业的发展。
中科院武汉植物园果树分子育种学科组深入开展了桃功能基因组学研究，并取得一系列进展。该课题组王鲁研究人员通过RNA-seq测序技术，进行了目前文献报道的桃的最高通量转录组测序。该项目建成不同品种花、叶、果等组织的11个RNA样品库，完成21.5G的测序量，获得含有完整编码区序列信息的基因超过25000个，其中超过2000个在桃基因组测序和注释中未被发现，属于新发现的基因。相关基因的可变剪切形式、表达量均得到了充分的分析结果。另外从全部的转录基因序列信息中分析得到简单重复序列（SSR分子标记）17979个；各不同基因型之间对比得到的SNP分子标记约一万个。这些序列信息、表达情况以及分子标记将有助于通过遗传图谱进行桃的关键农艺性状QTL定位，并开发与优异性状紧密连锁的分子标记，应于用桃分子标记辅助育种。相关论文以Deep RNA-Seq uncovers the peach transcriptome landscape为题发表于国际植物期刊《植物分子生物学》（Plant Molecular Biology）上。
同时，该学科组通过对红叶桃、普通桃相关基因序列、表达情况的比较分析，发现光呼吸相关的信号通路部分基因（GDCH 和GOX）在遮光、热胁迫处理以后表达量上升，而花青素相关的结构与调节基因则呈下降趋势。在拟南芥的花青素合成结构基因chi的突变体中发现，虽然该突变体不能积累花青素，但在相关条件下，GDCH 和GOX基因同样出现表达上调。这些结果表明光呼吸信号途径中的部分基因可能是花青素合成和积累途径的拮抗调节因子。该结果发表在林业科学SCI期刊Tree Genetics & Genomes（JCR专业领域排名top10%）上。
图1 桃转录组基因和转录因子的分类及其组织表达特性
图2 红叶桃叶不同发育时期中花青素含量及相关代谢途径基因的动态变化
生物谷推荐的英文摘要
Tree Genetics & Genomes DOI 10.1007/s11295-012-0552-1
Coordinated regulation of anthocyanin biosynthesis through photorespiration and temperature in peach (Prunus persica f. atropurpurea)
Ying Zhou, Dong Guo, Jing Li, Jun Cheng, Hui Zhou, Chao Gu, Sue Gardiner, Yue-Peng Han
The usual red color of young leaves of peach (Prunus persica f. atropurpurea) is due to the accumulation of anthocyanin. Real-time PCR analysis revealed a strong correlation between the expression levels of anthocyanin biosynthetic genes and anthocyanin content in leaves at different developmental stages. The expression profiles of both anthocyanin biosynthetic genes and photorespiratory genes showed significant changes in leaves held in the dark or exposed to heat stress, compared with controls. The expression of anthocyanin biosynthetic genes dramatically decreased in peach red leaves following dark or heat treatments, resulting in a significant decrease of anthocyanin accumulation. However, the photorespiration-related genes GDCH and GOX exhibited increased expression in peach leaves after dark or heat treatment. Moreover, the expression levels of GDCH and GOX in the Arabidopsis chi/f3′h mutant that does not accumulate anthocyanins were higher than in the wild type. Overall, these results support the hypothesis that photorespiration-related genes might be involved in the regulation of anthocyanin biosynthesis. This finding provides a new insight into our understanding of the mechanism underlying the control of anthocyanin biosynthesis in plants.
