马铃薯野生种（Solanum pinnatisectum）块茎变紫的光谱效应及其分子机理

The color of potato tubers are mainly controlled by genetic factors, tuber color is one of important variety characteristics of potato, and it will directly affect the appearance quality, nutritional value and utilization of the tubers. The study shows that potato purple tubers contain anthocyanins rich, anthocyanin synthesis in dark-grown underground tubers usually not directly dependent on light, and they are non-light-dependent anthocyanin production type. However, we found that the withe tubers from diploid potato wild species（Solanum pinnatisectum）turn purple during storage. The preliminary experiments show that synthesis and accumulation of anthocyanins in the withe tubers were mainly induced by light, make the tubers turn purple. The results show that these tubers are typical light-dependent anthocyanin production type. In present study, the tubers of S. pinnatisectum as materials, the differential expression of genes in tubers dealt with different light or dark will be analyzed by RT-PCR, SSH and Real time-PCR methods. The influence of light quality under identical light intensity on anthocyanin biosynthesis of tubers will be investigated. The differential expression of light receptor genes, light signal transduction intermediate genes, anthocyanin biosynthesis related genes will be found, and the relationship between gene expression and tuber anthocyanin synthesis and accumulation will be clarified, the expressed new genes induced by light will be explored. In present study, it will be elucidated that physiological, biochemical basis and molecular mechanism of biosynthesis of purple pigments induced by light in S. pinnatisectum tubers. These results will have significance to the quality improvement and gene engineering breeding of potato, as well as provide a new model plant for investigation of light-dependent anthocyanin production type.

马铃薯块茎的颜色主要受遗传因素制约，块茎颜色将直接影响其外观品质、营养价值和利用方式，是马铃薯的重要品种特性。马铃薯紫色块茎中含有丰富的花色苷，生长在黑暗中的地下块茎，其花色苷合成通常不直接依赖于光照，属非依光型。然而，我们发现二倍体马铃薯野生种Solanum pinnatisectum的白色块茎在贮藏过程中受光照影响而变成深紫色，表现为典型依光型特点。本研究以上述块茎为材料，用不同光源处理，找出有效作用光谱；用RT-PCR、Realtime-PCR和SSH法对有效光谱和暗处理的块茎进行基因差异表达分析，从中发掘光诱导或光敏感基因，并通过遗传转化等手段探明光受体、光信号中间体与块茎花色苷合成的关系，提出光诱导块茎变紫的生理生化基础和分子机制，补充和丰富花色苷光诱导合成的理论，获得新的基因资源，对马铃薯品质改良和基因工程育种具有重要意义，也为依光型花色苷的生物合成研究提供了一个新的模式植物。

马铃薯块茎的颜色是一个重要的品质和品种特性。以马铃薯野生种Solanum pinnatisectum白色块茎光照后变成紫色这一现象为切入点，用不同光谱的LED光源研究了光质效应，发现蓝光为诱导块茎变紫的最有效作用光谱，其次是自然光；运用第二代高通量测序技术，分别对蓝光、自然光处理和暗处理块茎进行了转录组分析，通过组装、注释和基因表达差异的分析，发掘出了一批花色素苷合成相关的结构基因、光受体和转录因子基因序列；利用qRT-PCR检测发现，花色苷生物合成相关结构基因中，强烈受蓝光和自然光诱导上调表达的有CHS、CHI、F3'5'H、DFR 、ANS、3GT、5GT和AMT，其次是4CL、BZ1、F3'H和F3H基因也有所上调，而C4H和PAL变化不明显，以F3'5'H和ANS等对蓝光最为敏感；在蓝光和自然光下，光受体Cryptochrome和phototropin-2基因均显著上调，其次是Cryptochrome 1和UVR8也有所上调，而phototropin-1基因表达明显下调，以Cryptochrome对蓝光最为敏感；在蓝光和自然光照下，转录因子bHLH、MYB113和an2基因表现为显著上调，JAF13基因也有所上调，而AN11基因有所下调，以MYB113对蓝光最为敏感；在蓝光和自然光下，光信号中间体HY5和CaSR基因显著上调表达，而以CaSR对蓝光最为敏感。用CRISPR/Cas9技术对发现的新基因进行功能分析，获得部分抗性植株。综合以上研究提出了光诱导马铃薯野生种块茎变紫的可能分子生物学机制，研究结果补充和丰富花色素苷光诱导生物合成的理论，为薯色品质改良和基因工程育种提供了基因资源，也为依光型花色苷的合成机理研究提供一个新的模式植物。