Zhang Rui, Zhang Jiao, Xu Yue-Xia, Sun Jun-Mei, Dai Shao-Jun, Shen Hui, Yan Yue-Hong
Eastern China Conservation Centre for Wild Endangered Plant Resources, Shanghai Chenshan Botanical Garden, Shanghai, China.
College of Life Science, Shanghai Normal University, Shanghai, China.
Front Plant Sci. 2024 Jun 21;15:1410554. doi: 10.3389/fpls.2024.1410554. eCollection 2024.
Several studies of MADS-box transcription factors in flowering plants have been conducted, and these studies have indicated that they have conserved functions in floral organ development; MIKC-type MADS-box genes has been proved to be expanded in ferns, however, few systematic studies of these transcription factors have been conducted in non-seed plants. Although ferns and seed plants are sister groups, they exhibit substantial morphological differences.
Here, we clarified the evolution of MADS-box genes across 71 extant fern species using available transcriptome, genome, and gene expression data.
We obtained a total of 2,512 MADS-box sequences, ranging from 9 to 89 per species. The most recent common ancestor (MRCA) of ferns contained approximately three type I genes and at least 5-6 type II MADS-box genes. The domains, motifs, expression of type I and type II proteins, and the structure of the both type genes were conserved in ferns as to other land plants. Within type II genes, MIKC*-type proteins are involved in gametophyte development in ferns; MIKC-type proteins have broader expression patterns in ferns than in seed plants, and these protein sequences are likely conserved in extant seed plants and ferns because of their diverse roles in diploid sporophyte development. More than 90% of MADS-box genes are type II genes, and MIKC genes, especially CRM1 and CRM6-like genes, have undergone a large expansion in leptosporangiate ferns; the diverse expression patterns of these genes might be related to the fuctional diversification and increased complexity of the plant body plan. Tandem duplication of CRM1 and CRM6-like genes has contributed to the expansion of MIKC genes.
This study provides new insights into the diversity, evolution, and functions of MADS-box genes in extant ferns.
已经对开花植物中的MADS-box转录因子进行了多项研究，这些研究表明它们在花器官发育中具有保守功能；然而，已证明MIKC型MADS-box基因在蕨类植物中有所扩展，但对这些转录因子在非种子植物中尚未进行过系统研究。尽管蕨类植物和种子植物是姊妹类群，但它们表现出显著的形态差异。
在这里，我们利用现有的转录组、基因组和基因表达数据，阐明了71种现存蕨类植物中MADS-box基因的进化情况。
我们总共获得了2512个MADS-box序列，每个物种的序列数从9个到89个不等。蕨类植物的最近共同祖先（MRCA）包含大约3个I型基因和至少5-6个II型MADS-box基因。I型和II型蛋白的结构域、基序、表达以及这两种类型基因的结构在蕨类植物中与其他陆地植物一样是保守的。在II型基因中，MIKC*型蛋白参与蕨类植物的配子体发育；MIKC型蛋白在蕨类植物中的表达模式比在种子植物中更广泛，并且由于它们在二倍体孢子体发育中的多种作用，这些蛋白序列在现存种子植物和蕨类植物中可能是保守的。超过90%的MADS-box基因是II型基因，并且MIKC基因，特别是CRM1和CRM6样基因，在薄囊蕨类植物中经历了大量扩增；这些基因的不同表达模式可能与植物体结构的功能多样化和复杂性增加有关。CRM1和CRM6样基因的串联重复促成了MIKC基因的扩增。
本研究为现存蕨类植物中MADS-box基因的多样性、进化和功能提供了新的见解。
