Thangavel Gokilavani, Nayar Saraswati
Division of Plant Molecular Biology, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India.
Front Plant Sci. 2018 Apr 18;9:510. doi: 10.3389/fpls.2018.00510. eCollection 2018.
MADS box transcription factors have been studied extensively in flowering plants but remain less studied in non-seed plants. MADS box is one such example of a gene which is prevalent across many classes of plants ranging from chlorophyta to embryophyta as well as fungi and animals. MADS box transcription factors are of two types, Type I and Type II. Type II transcription factors (TF) that consist of a MADS domain, I region, K domain, and C terminal domain are discussed in this review. The Type II/ MIKC class is widespread across charophytes and all major lineages of land plants but unknown in green and red algae. These transcription factors have been implicated in floral development in seed plants and thus the question arises, "What is their role in non-seed plants?" From the studies reviewed here it can be gathered that unlike seed plants, MIKC genes in non-seed plants have roles in both gametophytic and sporophytic generations and contribute to the development of both vegetative and reproductive structures. On the other hand as previously observed in seed plants, MIKC genes of non-seed plants have a conserved role during gametophyte development. With respect to evolution of MIKC genes in non-seed plants, the number of common ancestors is probably very few at each branch. The expansion of this gene family in seed plants and increased plant complexity seem to be correlated. As gradually the genomes of non-seed plants are becoming available it is worthwhile to gather the existing information about MADS box genes in non-seed plants. This review highlights various MIKC MADS box genes discovered so far in non-seed plants, their possible roles and an insight into their evolution.
MADS盒转录因子在开花植物中已得到广泛研究，但在非种子植物中的研究仍较少。MADS盒就是这样一个基因实例，它在从绿藻门到有胚植物以及真菌和动物等许多植物类别中都很普遍。MADS盒转录因子有两种类型，I型和II型。本文将讨论由MADS结构域、I区、K结构域和C末端结构域组成的II型转录转录因子（TF）。II型/ MIKC类广泛存在于轮藻和所有主要陆地植物谱系中，但在绿藻和红藻中未知。这些转录因子与种子植物的花发育有关，因此问题就出现了，“它们在非种子植物中的作用是什么？”从这里回顾的研究可以看出，与种子植物不同，非种子植物中的MIKC基因在配子体和孢子体世代中都起作用，并有助于营养和生殖结构的发育。另一方面，正如之前在种子植物中观察到的那样，非种子植物的MIKC基因在配子体发育过程中具有保守作用。关于非种子植物中MIKC基因的进化，每个分支上的共同祖先数量可能非常少。这个基因家族在种子植物中的扩展与植物复杂性的增加似乎相关。随着非种子植物的基因组逐渐可用，收集有关非种子植物中MADS盒基因的现有信息是值得的。这篇综述重点介绍了迄今为止在非种子植物中发现的各种MIKC MADS盒基因、它们可能的作用以及对其进化的见解。
