Fan Sheng, Zhang Dong, Xing Libo, Qi Siyan, Du Lisha, Wu Haiqin, Shao Hongxia, Li Youmei, Ma Juanjuan, Han Mingyu
College of Horticulture, Northwest A&F University, Yangling, 712100, China.
Mol Genet Genomics. 2017 Aug;292(4):755-771. doi: 10.1007/s00438-017-1306-4. Epub 2017 Mar 17.
Although INDETERMINATE DOMAIN (IDD) genes encoding specific plant transcription factors have important roles in plant growth and development, little is known about apple IDD (MdIDD) genes and their potential functions in the flower induction. In this study, we identified 20 putative IDD genes in apple and named them according to their chromosomal locations. All identified MdIDD genes shared a conserved IDD domain. A phylogenetic analysis separated MdIDDs and other plant IDD genes into four groups. Bioinformatic analysis of chemical characteristics, gene structure, and prediction of protein-protein interactions demonstrated the functional and structural diversity of MdIDD genes. To further uncover their potential functions, we performed analysis of tandem, synteny, and gene duplications, which indicated several paired homologs of IDD genes between apple and Arabidopsis. Additionally, genome duplications also promoted the expansion and evolution of the MdIDD genes. Quantitative real-time PCR revealed that all the MdIDD genes showed distinct expression levels in five different tissues (stems, leaves, buds, flowers, and fruits). Furthermore, the expression levels of candidate MdIDD genes were also investigated in response to various circumstances, including GA treatment (decreased the flowering rate), sugar treatment (increased the flowering rate), alternate-bearing conditions, and two varieties with different-flowering intensities. Parts of them were affected by exogenous treatments and showed different expression patterns. Additionally, changes in response to alternate-bearing and different-flowering varieties of apple trees indicated that they were also responsive to flower induction. Taken together, our comprehensive analysis provided valuable information for further analysis of IDD genes aiming at flower induction.
尽管编码特定植物转录因子的不定域（IDD）基因在植物生长发育中具有重要作用，但对于苹果IDD（MdIDD）基因及其在花诱导中的潜在功能却知之甚少。在本研究中，我们在苹果中鉴定出20个假定的IDD基因，并根据它们的染色体位置对其进行命名。所有鉴定出的MdIDD基因都共享一个保守的IDD结构域。系统发育分析将MdIDDs和其他植物IDD基因分为四组。对化学特性、基因结构以及蛋白质-蛋白质相互作用预测的生物信息学分析证明了MdIDD基因的功能和结构多样性。为了进一步揭示它们的潜在功能，我们进行了串联、共线性和基因重复分析，结果表明苹果和拟南芥之间存在几对IDD基因的同源物。此外，基因组重复也促进了MdIDD基因的扩增和进化。定量实时PCR显示，所有MdIDD基因在五种不同组织（茎、叶、芽、花和果实）中均表现出不同的表达水平。此外，还研究了候选MdIDD基因在各种条件下的表达水平，包括GA处理（降低开花率）、糖处理（提高开花率）、隔年结果条件以及两个开花强度不同的品种。其中部分基因受外源处理影响，表现出不同的表达模式。此外，对苹果树隔年结果和不同开花品种的响应变化表明，它们对花诱导也有响应。综上所述，我们的综合分析为进一步研究旨在花诱导的IDD基因提供了有价值的信息。
