The Analysis of Genes and Phytohormone Metabolic Pathways Associated with Leaf Shape Development in Liriodendron chinense via De Novo Transcriptome Sequencing.

Jikai Ma,Jiayu Li,Lingmin Wei,Huogen Li

doi:10.3390/genes9120577

Abstract

The leaf, a photosynthetic organ that plays an indispensable role in plant development and growth, has a certain ability to adapt to the environment and exhibits tremendous diversity among angiosperms. Liriodendron chinense, an ancestral angiosperm species, is very popular in landscaping. The leaf of this species has two lobes and resembles a Qing Dynasty Chinese robe; thus, leaf shape is the most valuable ornamental trait of the tree. In this work, to determine the candidate genes associated with leaf development in L. chinense, scanning electron microscopy (SEM) was employed to distinguish the developmental stages of tender leaves. Four stages were clearly separated, and transcriptome sequencing was performed for two special leaf stages. Altogether, there were 48.23 G clean reads in the libraries of the two leaf developmental stages, and 48,107 assembled unigenes were annotated with five databases. Among four libraries, 3118 differentially expressed genes (DEGs) were enriched in expression profiles. We selected ten DEGs associated with leaf development and validated their expression patterns via quantitative real-time PCR (qRT-PCR) assays. Most validation results were closely correlated with the RNA-sequencing data. Taken together, we examined the dynamic process of leaf development and indicated that several transcription factors and phytohormone metabolism genes may participate in leaf shape development. The transcriptome data analysis presented in this work aims to provide basic insights into the mechanisms mediating leaf development, and the results serve as a reference for the genetic breeding of ornamental traits in L. chinense.

Highlights

Since Darwin’s pioneering study, a long-standing challenge in biology has been the elucidation of the genetic basis of morphological evolution [1]
The results indicated the evolutionary transcriptomes and gene networks involved in leaf development and characterized BOP, a KNOTTED1-LIKE HOMEOBOX (KNOX) family gene that participates in the establishment of leaf morphology and fruit maturity of tomato and repeatedly acts in leaf shape formation [1]
We considered that the leaf developmental be separated into four stages: P1, P2, P3 and P4

Summary

Introduction

Since Darwin’s pioneering study, a long-standing challenge in biology has been the elucidation of the genetic basis of morphological evolution [1]. A conspicuous angiosperm trait, presents enormous diversity and variability [2]. Despite this profound diversity in shape, leaf morphology is classified into simple and compound types. Both simple and compound leaves initiate from a pluripotent clustered cell of the shoot apical meristem (SAM) dome, a process followed by blade growth [3,4]. Previous evidence has demonstrated that leaf diversity, from the formation of the tiny SAM to lateral leaf outgrowth, is controlled by gene regulatory networks (GRNs) and signaling pathways [6]

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