Ruiz-Estévez Mercedes, Bakkali Mohammed, Martín-Blázquez Rubén, Garrido-Ramos Manuel A
Departamento de Genética, Facultad de Ciencias, Universidad de Granada, 18071 Granada, Spain.
Genes (Basel). 2017 Oct 17;8(10):275. doi: 10.3390/genes8100275.
We report and discuss the results of a quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis of the expression patterns of seven three amino acid loop extension () homeobox genes (four () and three () genes) identified after next generation sequencing (NGS) and assembly of the sporophyte and gametophyte transcriptomes of the endangered fern species . Among the four genes, two belonged to the class and the other two belonged to the class. Analysis of the deduced amino acid sequences supported the typical domain structure of both types of TALE proteins, and the homology to TALE proteins of mosses, lycophytes, and seed plant species. The expression analyses demonstrate that these homeodomain proteins appear to have a key role in the establishment and development of the gametophyte and sporophyte phases of lifecycle, as well as in the control of the transition between both phases. VsKNAT3 (a KNOX2 class protein) as well as VsBELL4 and VsBELL10 proteins have higher expression levels during the sporophyte program. On the contrary, one protein (VsKNAT6) and one KNOX2 protein (VsKNAT4) seem important during the development of the gametophyte phase. homeobox genes might be among the key regulators in the gametophyte-to-sporophyte developmental transition in regular populations that show alternation of generations, since some of the genes analyzed here (, , , and ) are upregulated in a non-alternating population in which only independent gametophytes are found (they grow by vegetative reproduction outside of the range of sporophyte distribution). Thus, these four genes might trigger the vegetative propagation of the gametophyte and the repression of the sexual development in populations composed of independent gametophytes. This study represents a comprehensive identification and characterization of homeobox genes in , and gives novel insights about the role of these genes in fern development.
我们报告并讨论了对七种三氨基酸环延伸（TALE）同源异型框基因（四个KNOX基因和三个BELL基因）表达模式进行定量逆转录聚合酶链反应（qRT-PCR）分析的结果，这些基因是在对濒危蕨类植物中华水韭（Isoetes sinensis）的孢子体和配子体转录组进行下一代测序（NGS）和组装后鉴定出来的。在四个KNOX基因中，两个属于KNOX1类，另外两个属于KNOX2类。对推导的氨基酸序列的分析支持了这两种类型TALE蛋白的典型结构域结构，以及与苔藓、石松和种子植物物种的TALE蛋白的同源性。表达分析表明，这些同源异型结构域蛋白似乎在中华水韭生命周期的配子体和孢子体阶段的建立和发育中，以及在两个阶段之间转换的控制中发挥关键作用。VsKNAT3（一种KNOX2类蛋白）以及VsBELL4和VsBELL10蛋白在孢子体发育过程中具有较高的表达水平。相反，一种BELL蛋白（VsKNAT6）和一种KNOX2蛋白（VsKNAT4）在配子体阶段的发育过程中似乎很重要。TALE同源异型框基因可能是在具有世代交替的正常种群中配子体到孢子体发育转变的关键调节因子之一，因为这里分析的一些基因（VsKNAT3、VsBELL4、VsBELL10和VsKNAT6）在一个仅发现独立配子体的非交替种群中上调（它们通过营养繁殖在孢子体分布范围之外生长）。因此，这四个基因可能触发配子体的营养繁殖，并抑制由独立配子体组成的种群中的有性发育。这项研究代表了对中华水韭TALE同源异型框基因的全面鉴定和表征，并为这些基因在蕨类植物发育中的作用提供了新的见解。
