Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing, China.
Plant Science and Technology College, Beijing University of Agriculture, Beijing, China.
Plant J. 2019 Nov;100(3):572-590. doi: 10.1111/tpj.14470. Epub 2019 Aug 22.
Anthocyanin pigments contribute to the red color of apple (Malus × domestica) fruit and have a major influence on their ornamental, dietary and market value. In this study, we investigated the potential role of long noncoding RNAs (lncRNAs) in anthocyanin biosynthesis. RNA-seq analysis of apple peels from the 'Red Fuji' cultivar during light-induced rapid anthocyanin accumulation revealed 5297 putative lncRNAs. Differential expression analysis further showed that lncRNAs were induced during light treatment and were involved in photosynthesis. Using the miRNA-lncRNA-mRNA network and endogenous target mimic (eTM) analysis, we predicted that two differentially expressed lncRNAs, MLNC3.2 and MLNC4.6, were potential eTMs for miRNA156a and promoted the expression of the SPL2-like and SPL33 transcription factors. Transient expression in apple fruit and stable transformation of apple callus showed that overexpression of the eTMs and SPLs promoted anthocyanin accumulation, with the opposite results in eTM and SPL-silenced fruit. Silencing or overexpressing of miR156a also affected the expression of the identified eTMs and SPLs. These results indicated that MLNC3.2 and MLNC4.6 function as eTMs for miR156a and prevent cleavage of SPL2-like and SPL33 by miR156a during light-induced anthocyanin biosynthesis. Our study provides fundamental insights into lncRNA involvement in the anthocyanin biosynthetic pathway in apple fruit.
花色苷色素赋予苹果（Malus × domestica）果实红色，并对其观赏、饮食和市场价值有重大影响。在这项研究中，我们研究了长非编码 RNA（lncRNA）在花色苷生物合成中的潜在作用。对‘红富士’品种果皮在光照诱导快速积累花色苷过程中的 RNA-seq 分析显示了 5297 个推定的 lncRNA。差异表达分析进一步表明，lncRNA 在光照处理下被诱导，并参与光合作用。利用 miRNA-lncRNA-mRNA 网络和内源性靶标模拟（eTM）分析，我们预测了两个差异表达的 lncRNA，MLNC3.2 和 MLNC4.6，是 miRNA156a 的潜在 eTM，并促进了 SPL2 样和 SPL33 转录因子的表达。在苹果果实中的瞬时表达和苹果愈伤组织中的稳定转化表明，eTM 和 SPL 的过表达促进了花色苷的积累，而在 eTM 和 SPL 沉默的果实中则得到相反的结果。miR156a 的沉默或过表达也影响了鉴定的 eTM 和 SPL 的表达。这些结果表明 MLNC3.2 和 MLNC4.6 作为 miR156a 的 eTM，在光照诱导花色苷生物合成过程中防止 miR156a 对 SPL2 样和 SPL33 的切割。我们的研究为 lncRNA 参与苹果果实花色苷生物合成途径提供了基础见解。
