Two LEAFY homologs ILFY1 and ILFY2 control reproductive and vegetative developments in Isoetes L.

Xing Liu,Tao Yang,You-Hao Guo,Ming-Fang Du

doi:10.1038/s41598-017-00297-3

Abstract

LEAFY (LFY) is a plant-specific transcription factor, which is found in algae and all land plants. LFY homologs exert ancestral roles in regulating cell division and obtain novel functions to control floral identity. Isoetes L. is an ancient genus of heterosporous lycophytes. However, characters about LFY homologs in lycophytes remain poorly investigated. In this study, two LFY homologs, ILFY1 and ILFY2, were cloned from five Isoetes species, including I. hypsophila, I. yunguiensis, I. sinensis, I. orientalis, and I. taiwanensis. The full length of ILFY1 was 1449–1456 bp with an open reading frame (ORF) of 927–936 bp. The full length of ILFY2 was 1768 bp with ORF of 726 bp. Phylogenetic tree revealed that ILFY1 and ILFY2 were separated into two clades, and I. hypsophila were separated with the others. Expression analysis demonstrated that IsLFY1 and IsLFY2 for I. sinensis did not show functional diversity. The two transcripts were similarly accumulated in both vegetative and reproductive tissues and highly expressed in juvenile tissues. In addition, the IsLFY1 and IsLFY2 transgenic Arabidopsis similarly did not promote precocious flowering, and they were inactive to rescue lfy mutants. The results facilitate general understandings about the characteristics of LFY in Isoetes and evolutionary process.

Highlights

LFY homologs are present in free-sporing land plants, including lycophytes, ferns or their allies and bryophytes[1, 2, 20]
The full-length of ILFY genes were cloned from five Isoetes species, including I. hypsophila, I. yunguiensis, I. sinensis, I. orientalis, and I. taiwanensis
The open reading frame (ORF) sequences of ILFY1 and ILFY2 were identical for I. yunguiensis, I. sinensis, I. orientalis, and I. taiwanensis

Summary

Introduction

LFY homologs are present in free-sporing land plants, including lycophytes, ferns or their allies and bryophytes[1, 2, 20]. The PpLFY proteins play critical roles in controlling first zygotic cell division[21] Whereas they are inactive to complement Arabidopsis lfy mutants[1]. Isoetes possesses an important position in phylogenetic evolution, characters and functions of LFY homologs for Isoetes (referred as ILFY) are still ambiguous In this present study, we cloned two ILFY paralogs, including ILFY1 and ILFY2. We created transgenic Arabidopsis plants, which were constitutively expressed IsLFY1 and IsLFY2 under the control of the cauliflower mosaic virus 35S promoter, respectively. This comprehensive study will facilitate our understandings about the roles of LFY homologs in Isoetes and evolutionary process

Methods

Results

Conclusion