miR156a及其靶基因SPLs参与调控连作草莓酚酸类自毒物质生物合成的分子机制

Continuous cropping obstacle has become a major problem restricting the sustainable development of strawberry industry in China. The autotoxicity of phenolic acids is one of most important factors for continuous cropping obstacle of strawberry. miR156a and its target SPLs play an important role in the biosynthesis of phenolic acids of continuous cropping strawberry plants. Based on the previous research, the main content of this study was as follows: 1) at different growth stage of strawberry plants, the expression patterns of miR156a and its target SPLs in different tissue were detected by qRT-PCR, and the changes of phenolic acid content in different tissue were detected by LC-MS, to provide the basis for the study on the function of target genes; 2) the the regulatory role of miR156a and its target SPLs in the change of phenolic acid content was analyzed between transgenic strawberry plants and control; 3) based on the above results, combined with RNA-seq and CHIP-seq analysis, the regulatory network of miR156a and its target SPLs in controlling phenolic acid biosythesis in strawberry plants was built. Expected results will reveal the molecular mechanisms of miR156a and its target SPLs regulating the biosynthesis of phenolic acids in the continuous cropping strawberry plants, and will provide new way and theoretical basis for the control of continuous cropping obstacle of strawberry and molecular breeding of high quality strawberry.

连作障碍已成为制约我国草莓产业可持续发展的重大问题。酚酸类物质的自毒作用是草莓连作障碍发生的最重要的原因之一。miR156a及其靶基因SPLs在连作草莓酚酸类自毒物质生物合成中扮演重要角色。在此基础上，本研究拟开展：1）继续利用qRT-PCR和LC-MS技术等，研究miR156a及其靶基因SPLs在正茬和连作草莓植株中的时空表达模式和对应时空酚酸类自毒物质含量变化情况，为目标基因功能研究提供依据；2）采用转基因技术等，阐明miR156a及其靶基因SPLs在酚酸类自毒物质含量变化中的功能；3）基于RNA-seq和CHIP-seq联合分析等，构建miR156a及其靶基因SPLs对酚酸类自毒物质生物合成的调控网络。预期成果将揭示miR156a及其靶基因SPLs参与调控连作草莓酚酸类自毒物质生物合成的分子机制，同时为草莓连作障碍控制和优质草莓分子育种提供新途径和理论依据。

连作障碍是制约我国草莓产业健康发展的重大问题。酚酸类物质的自毒作用是草莓连作障碍发生的最重要原因之一，但其分子机理尚不明确。本项目以“红颜”草莓品种为材料，明确了不同生育期、不同组织中正常和连作草莓植株中miR156a的表达量与酚酸类自毒物质含量变化趋势一致，靶基因SPL2/9/11的表达量与酚酸类自毒物质含量变化趋势相反的关系。转基因植株分析表明miR156a及靶基因SPL9/11表达量变化显著影响酚酸类自毒物质含量和苯丙烷代谢途径关键酶基因的表达量，明确了miR156a及其靶基因SPLs在草莓酚酸类自毒物质生物合成中的功能。结合高通量数据分析，初步揭示了miR156a通过靶基因SPLs直接结合或经FaMYB间接结合Fa4CL、FaC4H调控酚酸类自毒物质生物合成的分子机制。研究结果为全面解析连作草莓自毒作用机理奠定了理论基础，也为草莓连作障碍防治提供了新思路和研究方法。