Transcriptome analyses provide insights into development of the Zingiber zerumbet flower, revealing potential genes related to floral organ formation and patterning

Can the anatomy of abnormal flowers elucidate relationships of the androecial members in the ginger (Zingiberaceae)?

“…The results of developmental work on unlobed or bilobed or trilobed labellum (Fig. 1) [7,16,24,27,58,60,73] generally share in ontogenic aspects and present a similar pattern: the two abaxial inner androecial members are joined through intercalary growth, fusing basally, to produce (the center of ) the labellum. The two adaxial outer androecial members form two lateral staminodes, developing into small teeth at the base of the labellum, or petaloid free from the labellum, or lateral lobe fused with the central lobe of labellum to form the trilobed structure.…”

“…It remains ambiguous whether the anterior, abaxial outer androecial member aborts early or never initiates since the cells in this region are indistinguishable from surrounding cells and fusion of the two segments of labellum derived from common primordia may almost be congenital. Recent transcriptome on Zingiber zerumbet, a trilobed labellum species, has investigated the implicated molecular mechanism that boundary genes may be involved in floral organ fusion by down-regulation, thus resulting in loss of boundary between the androecial primordia [73]. The silence of B-and C-class MADS-box genes in Nigella damascena not only led to homeotic conversion, but also boundary shift between floral whorls [68].…”

Transcriptome-Wide Analyses Provide Insights into Development of the Hedychium coronarium Flower, Revealing Potential Roles of PTL

“…Recent research suggests that particular events of gene duplication and differential losses of paralogs could underlie the tendency towards staminode laminarization across the different families that comprise the order [16,18]. However, this body of research has focused on analyzing the functional evolution of oral MADS-box genes and its relation with oral organ inception and diversi cation in members of the Zingiberales, and as such cannot uncover the molecular mechanisms underlying particular organ morphologies that emerge during late ower development, such as the synsepalous calyx fused by the margins of adjacent sepal primordia through intercalary growth or the variable fusion patterns among petaloid staminodes that will form the labellum in Zingiberaceae species [19].…”

“…However, there are only a few functional studies focusing on the role of boundary gene orthologs in monocot oral development, mainly focused in the grasses. While a recent study in Zingiber zerumbet has identi ed several boundary genes which may contribute to the formation of the synsepalous calyx in this species [19], how these genes exert their function during oral organ differentiation and growth still needs further exploration. In addition, the existence of common primordia that emerge during early oral development in many Zingiberales (e.g.…”

“…RNA-seq, a cost-effective and highly e cient technology built on small-read sequencing, has accelerated gene discovery across a diverse set of species, while extending our comprehension of complex gene regulatory networks to a wide breath of organisms from the tree of life. In recent years, there has been an explosion in the use of plant transcriptomes as part of a comparative analysis pipeline to isolate homeotic gene orthologs, as well as to study differential gene expression among owers at different developmental stages in a variety of nonmodel species, including some within the Zingiberales [19,[27][28][29][30][31][32]. Here, we conducted de novo transcriptome sequencing of two oral developmental stages for H. coronarium and used comparative transcriptomics combined with Real-time quantitative PCR (qRT-PCR) to investigate gene expression patterns of orthologs of selected ABC-class homeotic genes.…”