Date Published: March 14, 2019
Publisher: Public Library of Science
Author(s): Aixiang Dong, Jingjing Wang, Huali Zhang, Haibo Xin, Zhengnan Zhao, Fang Liang, Zijing Li, Richen Cong, Yan Lin, Lina Song, Lingling Tan, Pengwei Zhang, Rongfeng Cui, Turgay Unver.
Salvia splendens is a perennial, ornamental herbaceous flower that is widely cultivated as a bedding plant in gardens. The development of novel S. splendens cultivars and investigating the relevant molecular mechanisms are of great significance. In this study, RNA-sequencing and real-time PCR methods were used to analyze the possible molecular mechanism of S. splendens mutant, SX919M. From the wild-type S. splendens 919CK, we firstly selected a natural mutant, SX919M, which displayed multiple branches, clustered spheroids, and radial symmetrical inflorescence with higher numbers of calyces, ovules, stamens, and perianth tubes. Further, the RNA-seq was used to identify the differentially expressed genes (DEGs) in the mutant which included a total of 3568 upregulated and 3290 downregulated unigenes. We further observed that the indole alkaloid biosynthesis pathway showed the highest DEG enrichment, which was supported by a significant increase in the IAA content in mutant SX919M. In addition, we validated three DEGs, namely, CL2200.Contig2_All encoding methyl IAA esterase, CL12462.Contig1_All and CL12462.Contig2_All, which encoded strictosidine synthase, upregulated in mutant SX919M. We selected a novel S. splendens germplasm SX919M with a high ornamental value and determined that the upregulation of IAA biogenesis may be associated with its development.
Salvia L., with nearly 1000 species of shrubs, herbaceous perennials, and annuals, is the largest genus in the mint family (Lamiaceae: Nepetoideae: Mentheae: Salviinae) [1–4]. The genus is widely distributed throughout the world. Many species of this genus, such as S. officinalis and S. miltiorrhiza (Danshen), are extensively used for culinary purposes, essential oil production, and Chinese herbal remedies . Additionally, species such as S. splendens are used as ornamental plants, valued for their flowers and aromatic foliage.
In this study, we selected an outstanding S. splenden mutant, SX919M, from a traditional S. splenden cultivar Ker-Gawler Qiji (wild-type 919CK). When compared with the wild-type, SX919M is characterized with multiple branches, clustered spheroids, and radial symmetrical inflorescence (Fig 1). Generally, SX919M is a valuable germplasm for garden landscaping of public parks. To investigate the possible molecular mechanism of its development, we performed a comparative transcriptome analysis between wild-type and mutant.