Journal Article

Functional conservation and divergence of five SEPALLATA-like genes from a basal eudicot tree, Platanus acerifolia

Bao, Manzhu, Zhang, Sisi, Lu, Shunjiao, Zhang, Jiaqi, Yi, Shuangshuang, Liu, Guofeng, Han, Hongji, Liu, Lei

2017

Overview

SEPALLATA (SEP) genes have been well characterized in core eudicots and some monocots, and they play important and diverse roles in plant development, including flower meristem initiation, floral organ identity, and fruit development and ripening. However, the knowledge on the function and evolution of SEP-like genes in basal eudicot species is very limited. Here, we cloned and identified five SEP-like genes from London plane (Platanus acerifolia), a basal eudicot tree that is widely used for landscaping in cities. Sequence alignment and phylogenetic analysis indicated that three genes (PlacSEP1.1, PlacSEP1.2, and PlacSEP1.3) belong to the SEP1/2/4 clade, while the other two genes (PlacSEP3.1 and PlacSEP3.2) are grouped into the SEP3 clade. Quantitative real-time PCR (qRT-PCR) analysis showed that all PlacSEPs, except PlacSEP1.1 and PlacSEP1.2, were expressed during the male and female inflorescence initiation, and throughout the flower and fruit development process. PlacSEP1.2 gene expression was only detected clearly in female inflorescence at April. PlacSEP1.3 and PlacSEP3.1 were also expressed, although relatively weak, in vegetative buds of adult trees. No evident PlacSEPs transcripts were detected in various organs of juvenile trees. Overexpression of PlacSEPs in Arabidopsis and tobacco plants resulted in different phenotypic alterations. 35S: PlacSEP1.1, 35S: PlacSEP1.3, and 35S: PlacSEP3.2 transgenic Arabidopsis plants showed evident early flowering, with less rosette leaves but more cauline leaves, while 35S: PlacSEP1.2 and PlacSEP3.1 transgenic plants showed no visible phenotypic changes. 35S: PlacSEP1.1 and 35S: PlacSEP3.2 transgenic Arabidopsis plants also produced smaller and curled leaves. Overexpression of PlacSEP1.1 and PlacSEP3.1 in tobacco resulted in the early flowering and producing more lateral branches. Yeast two-hybrid analysis indicated that Plac-SEPs proteins can form homo-or hetero-dimers with the Platanus APETALA1 (AP1)/FRUITFULL (FUL), B-, C-, and D-class MADS-box proteins in different interacting patterns and intensities. Our results suggest that the five PlacSEP genes may play important and divergent roles during floral initiation and development, as well as fruit development, by collaborating with FUL, B-, C-, and D-class MADS-box genes in London plane; PlacSEP1.3 and PlacSEP3.1 genes might also involve in vegetative bud growth and dormancy. The results provide valuable data for us to understand the functional evolution of SEP like genes in basal eudicot species.

• Publisher: Springer Science + Business Media,Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Agriculture / Arabidopsis / Arabidopsis - genetics / Arabidopsis Proteins - genetics / Biomedical and Life Sciences / branches / buds / cities / Cloning, Molecular / dormancy / Ecology / females / flowering / Flowers / Flowers - genetics / Flowers - growth & development / Forestry / fruiting / Fruits / Gene Expression Regulation, Plant / gene overexpression / genes / Homeodomain Proteins - genetics / juveniles / Landscaping / Leaves / Life Sciences / Liliopsida / Magnoliopsida - genetics / males / mature plants / meristems / Nicotiana - genetics / ORIGINAL ARTICLE / phenotype / Phenotypes / Phylogeny / Plant Proteins - genetics / Plant Proteins - metabolism / Plant Sciences / Plants / Plants, Genetically Modified / Platanus / Platanus acerifolia / protein-protein interactions / proteins / quantitative polymerase chain reaction / reverse transcriptase polymerase chain reaction / ripening / Seeds - genetics / Seeds - growth & development / sequence alignment / tobacco / Transcription Factors - genetics / Transgenic plants / Trees / two hybrid system techniques / Yeasts