Jiang Shuang, Luo Jun, Xu Fanjie, Zhang Xueying
Forestry and Pomology Research Institute, Shanghai Academy of Agriculture SciencesShanghai, China; Shanghai Key Laboratory of Protected Horticultural Technology, Shanghai Academy of Agriculture SciencesShanghai, China.
Front Plant Sci. 2016 Dec 21;7:1924. doi: 10.3389/fpls.2016.01924. eCollection 2016.
The triploid loquat () is a new germplasm with a high edible fruit rate. Under natural conditions, the triploid loquat has a low fruit setting ratio (not more than 10 fruits in a tree), reflecting fertilization failure. To unravel the molecular mechanism of gibberellin (GA) treatment to induce parthenocarpy in triploid loquats, a transcriptome analysis of fruit setting induced by GA was analyzed using RNA-seq at four different stages during the development of young fruit. Approximately 344 million high quality reads in seven libraries were assembled, yielding 153,900 unique transcripts with more than 79.9% functionally annotated transcripts. A total of 2,220, 2,974, and 1,614 differentially expressed genes (DEGs) were observed at 3, 7, and 14 days after GA treatment, respectively. The weighted gene co-expression network and Venn diagram analysis of DEGs revealed that sixteen candidate genes may play critical roles in the fruit setting after GA treatment. Five genes were related to auxin, in which one auxin synthesis gene of was upregulated, suggesting that auxin may act as a signal for fruit setting. Furthermore, ABA 8'-hydroxylase was upregulated, while ethylene-forming enzyme was downregulated, suggesting that multiple hormones may be involved in GA signaling. Four transcription factors, , , , and , were potentially negatively regulated in fruit setting, and two cell division-related genes, and , were upregulated. In addition, the expression of the GA receptor was downregulated by GA treatment, suggesting that the negative feedback mechanism in GA signaling may be regulated by . Altogether, the results of the present study provide information from a comprehensive gene expression analysis and insight into the molecular mechanism underlying fruit setting under GA treatment in .
三倍体枇杷（）是一种可食率高的新种质。在自然条件下，三倍体枇杷坐果率低（一棵树不超过10个果实），反映出受精失败。为了揭示赤霉素（GA）处理诱导三倍体枇杷单性结实的分子机制，在幼果发育的四个不同阶段，利用RNA测序技术对GA诱导坐果的转录组进行了分析。七个文库中约3.44亿条高质量 reads 被组装，产生了153,900个独特转录本，功能注释转录本超过79.9%。GA处理后3天、7天和14天分别观察到2,220个、2,974个和1,614个差异表达基因（DEG）。对DEG进行加权基因共表达网络和维恩图分析表明，16个候选基因可能在GA处理后的坐果过程中起关键作用。5个基因与生长素相关，其中一个生长素合成基因上调，表明生长素可能作为坐果信号。此外，ABA 8'-羟化酶上调，而乙烯形成酶下调，表明多种激素可能参与GA信号传导。四个转录因子，，，和，在坐果过程中可能受到负调控，两个与细胞分裂相关的基因，和，上调。此外，GA受体的表达在GA处理后下调，表明GA信号中的负反馈机制可能受调控。总之，本研究结果提供了全面基因表达分析的信息，并深入了解了GA处理下坐果的分子机制。
