Wang Jingjing, Wang Haibin, Ding Lian, Song Aiping, Shen Feng, Jiang Jiafu, Chen Sumei, Chen Fadi
College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China.
Jiangsu Province Engineering Lab for Modern Facility Agriculture Technology & Equipment, Nanjing, 210095, China.
Plant Mol Biol. 2017 Apr;93(6):593-606. doi: 10.1007/s11103-017-0584-x. Epub 2017 Jan 20.
Auxin regulates chrysanthemum petal elongation by promoting cell elongation. Transcriptomic analysis shows that auxin signal transduction may connect with other transcription factors by TCPs to regulate chrysanthemum petal elongation. As an ornamental species, Chrysanthemum morifolium has high ornamental and economic value. Petal size is the primary factor that influences the ornamental value of chrysanthemum, but the mechanism underlying the development of C. morifolium petals remains unclear. In our study, we tracked the growth of petals and found that the basal region of 'Jinba' petals showed a higher elongation rate, exhibiting rapid cell elongation during petal growth. During petal elongation growth, auxin was demonstrated to promote cell elongation and an increase in cell numbers in the petal basal region. To further study the molecular mechanisms underlying petal growth, the RNA-seq (high-throughput cDNA sequencing) technique was employed. Four cDNA libraries were assembled from petals in the budding, bud breaking, early blooming and full blooming stages of 'Jinba' flower development. Analysis of differentially expressed genes (DEGs) showed that auxin was the most important regulator in controlling petal growth. The TEOSINTEBRANCHED 1, CYCLOIDEA and PCF transcription factor genes (TCPs), basic helix-loop-helix-encoding gene (bHLH), glutaredoxin-C (GRXC) and other zinc finger protein genes exhibited obvious up-regulation and might have significant effects on the growth of 'Jinba' petals. Given the interaction between these genes in Arabidopsis thaliana, we speculated that auxin signal transduction might exhibit a close relationship with transcription factors through TCPs. In summary, we present the first comprehensive transcriptomic and hormone analyses of C. morifolium petals. The results offer direction in identifying the mechanism underlying the development of chrysanthemum petals in the elongated phase and have great significance in improving the ornamental characteristics of C. morifolium via molecular breeding.
生长素通过促进细胞伸长来调节菊花花瓣的伸长。转录组分析表明，生长素信号转导可能通过TCPs与其他转录因子相互作用，从而调节菊花花瓣的伸长。作为一种观赏植物，菊花具有很高的观赏价值和经济价值。花瓣大小是影响菊花观赏价值的主要因素，但菊花花瓣发育的潜在机制仍不清楚。在我们的研究中，我们追踪了花瓣的生长，发现‘金背大红’花瓣的基部区域伸长率较高，在花瓣生长过程中表现出快速的细胞伸长。在花瓣伸长生长过程中，生长素被证明能促进花瓣基部区域的细胞伸长和细胞数量增加。为了进一步研究花瓣生长的分子机制，我们采用了RNA测序（高通量cDNA测序）技术。从‘金背大红’花发育的现蕾期、破蕾期、初花期和盛花期的花瓣中组装了四个cDNA文库。差异表达基因（DEGs）分析表明，生长素是控制花瓣生长的最重要调节因子。玉米分枝1、环化酶和PCF转录因子基因（TCPs）、编码基本螺旋-环-螺旋的基因（bHLH）、谷氧还蛋白-C（GRXC）和其他锌指蛋白基因表现出明显上调，可能对‘金背大红’花瓣的生长有显著影响。鉴于这些基因在拟南芥中的相互作用，我们推测生长素信号转导可能通过TCPs与转录因子表现出密切关系。总之，我们首次对菊花花瓣进行了全面的转录组和激素分析。这些结果为确定菊花花瓣伸长阶段发育的潜在机制提供了方向，并且对于通过分子育种改善菊花的观赏特性具有重要意义。
