Plant Growth and Defense Signaling Laboratory, State Ministry of Education Key Laboratory of Integrated Management of Crop Pathogens and Insect Pests, Nanjing Agricultural University, Nanjing 210095, China.
BMC Genomics. 2013 Nov 20;14(1):806. doi: 10.1186/1471-2164-14-806.
The phytohormone auxin mediates a stunning array of plant development through the functions of AUXIN RESPONSE FACTORs (ARFs), which belong to transcription factors and are present as a protein family comprising 10-43 members so far identified in different plant species. Plant development is also subject to regulation by TRANSPARENT TESTA GLABRA (TTG) proteins, such as NtTTG2 that we recently characterized in tobacco Nicotiana tabacum. To find the functional linkage between TTG and auxin in the regulation of plant development, we performed de novo assembly of the tobacco transcriptome to identify candidates of NtTTG2-regulated ARF genes.
The role of NtTTG2 in tobacco growth and development was studied by analyzing the biological effects of gene silencing and overexpression. The NtTTG2 gene silencing causes repressive effects on vegetative growth, floral anthocyanin synthesis, flower colorization, and seed production. By contrast, the plant growth and development processes are promoted by NtTTG2 overexpression. The growth/developmental function of NtTTG2 associates with differential expression of putative ARF genes identified by de novo assembly of the tobacco transcriptome. The transcriptome contains a total of 54,906 unigenes, including 30,124 unigenes (54.86%) with annotated functions and at least 8,024 unigenes (14.61%) assigned to plant growth and development. The transcriptome also contains 455 unigenes (0.83%) related to auxin responses, including 40 putative ARF genes. Based on quantitative analyses, the expression of the putative genes is either promoted or inhibited by NtTTG2.
The biological effects of the NtTTG2 gene silencing and overexpression suggest that NtTTG2 is an essential regulator of growth and development in tobacco. The effects of the altered NtTTG2 expression on expression levels of putative ARF genes identified in the transcriptome suggest that NtTTG2 functions in relation to ARF transcription factors.
植物激素生长素通过生长素响应因子（ARF）的功能介导了一系列令人惊叹的植物发育，ARF 属于转录因子，迄今为止已在不同植物物种中鉴定出包含 10-43 个成员的蛋白质家族。植物发育也受到 TRANSPARENT TESTA GLABRA（TTG）蛋白的调节，例如我们最近在烟草 Nicotiana tabacum 中表征的 NtTTG2。为了在植物发育的调节中找到 TTG 和生长素之间的功能联系，我们进行了烟草转录组的从头组装，以鉴定 NtTTG2 调节的 ARF 基因的候选物。
通过分析基因沉默和过表达的生物学效应，研究了 NtTTG2 在烟草生长和发育中的作用。NtTTG2 基因沉默对营养生长、花色素合成、花色化和种子生产有抑制作用。相比之下，NtTTG2 的过表达促进了植物的生长和发育过程。NtTTG2 的生长/发育功能与通过烟草转录组的从头组装鉴定的假定 ARF 基因的差异表达相关。该转录组共包含 54906 个 unigenes，其中 30124 个 unigenes（54.86%）具有注释功能，至少 8024 个 unigenes（14.61%）被分配到植物生长和发育中。转录组还包含 455 个与生长素反应相关的 unigenes，包括 40 个假定的 ARF 基因。基于定量分析，假定基因的表达被 NtTTG2 促进或抑制。
NtTTG2 基因沉默和过表达的生物学效应表明，NtTTG2 是烟草生长和发育的重要调节剂。改变的 NtTTG2 表达对转录组中鉴定的假定 ARF 基因表达水平的影响表明，NtTTG2 与 ARF 转录因子有关。
