Xiao Yao, Kang Baoshan, Li Meng, Xiao Liangjun, Xiao Han, Shen Huolin, Yang Wencai
Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, Department of Vegetable Science, China Agricultural University, Beijing, China.
Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education of the People's Republic of China, Beijing, China.
RNA Biol. 2020 Apr;17(4):596-607. doi: 10.1080/15476286.2020.1721095. Epub 2020 Feb 2.
Phytoene synthase (PSY) has been considered as an important regulatory enzyme in carotenoids biosynthesis pathway. Previous study finds that the yellow fruit in var. accession PI 114490 is caused by loss-of-function of SlPSY1 due to -splicing between and an unknown gene transcribed from neighbour opposite strand DNA of . The genomic DNA sequences of between red and yellow-fruited tomato lines have one single-nucleotide polymorphism (SNP) in the fourth intron and one SSR in the intergenic region. In the current study, the cause of -splicing event was further investigated. The data showed that the previously defined unknown gene was a putative long non-coding RNA with three variants in many yellow-fruited tomato lines. The intronic SNP and intergenic SSR were tightly associated with -splicing event . However, transgenic tomato lines carrying the genomic DNA of from PI 114490 did not generate transcripts of and suggesting that only the intronic SNP could not cause the -splicing event. Over-expression of in red-fruited tomato line M82 did not have any phenotype change while over-expression of wild type resulted in altered leaf colour. Sub-cellular localization analysis showed that SlPSY1-ACoS-AS1 could not enter plastids where SlPSY1 has its enzyme activity. Mutation of in PI 114490 generated by CRISPR/Cas9 techniques resulted in red fruits implying that was essential to -splicing event . The results obtained here will extend knowledge to understand the mechanism of -splicing event and provide additional information for the regulation of carotenoids biosynthesis.
八氢番茄红素合酶（PSY）被认为是类胡萝卜素生物合成途径中的一种重要调控酶。先前的研究发现，PI 114490品种中的黄色果实是由于SlPSY1功能丧失所致，这是由于其与从 相邻反向链DNA转录的未知基因之间发生了剪接。红色和黄色果实番茄品系之间 的基因组DNA序列在第四个内含子中有一个单核苷酸多态性（SNP），在基因间区域有一个简单序列重复（SSR）。在本研究中，进一步探究了剪接事件的原因。数据显示，先前定义的未知基因是一个推定的长链非编码RNA，在许多黄色果实番茄品系中有三种变体。内含子SNP和基因间SSR与剪接事件紧密相关。然而，携带来自PI 114490的 基因组DNA的转基因番茄品系并未产生 和 的转录本，这表明仅内含子SNP不会导致剪接事件。在红色果实番茄品系M82中过表达 没有任何表型变化，而过表达野生型 则导致叶片颜色改变。亚细胞定位分析表明，SlPSY1-ACoS-AS1无法进入SlPSY1具有酶活性的质体。通过CRISPR/Cas9技术在PI 114490中对 进行突变产生了红色果实，这意味着 对于剪接事件至关重要。此处获得的结果将扩展对剪接事件机制的认识，并为类胡萝卜素生物合成的调控提供更多信息。
