Integrated Omics Analyses Identify Key Pathways Involved in Petiole Rigidity Formation in Sacred Lotus.

Ming Li,Ishfaq Hameed,Dongli He,Pingfang Yang,Dingding Cao

doi:10.3390/ijms21145087

Ming Li, Ishfaq Hameed + Show 3 more

Open Access

https://doi.org/10.3390/ijms21145087

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Abstract

Sacred lotus (Nelumbo nucifera Gaertn.) is a relic aquatic plant with two types of leaves, which have distinct rigidity of petioles. Here we assess the difference from anatomic structure to the expression of genes and proteins in two petioles types, and identify key pathways involved in petiole rigidity formation in sacred lotus. Anatomically, great variation between the petioles of floating and vertical leaves were observed. The number of collenchyma cells and thickness of xylem vessel cell wall was higher in the initial vertical leaves’ petiole (IVP) compared to the initial floating leaves’ petiole (IFP). Among quantified transcripts and proteins, 1021 and 401 transcripts presented 2-fold expression increment (named DEGs, genes differentially expressed between IFP and IVP) in IFP and IVP, 421 and 483 proteins exhibited 1.5-fold expression increment (named DEPs, proteins differentially expressed between IFP and IVP) in IFP and IVP, respectively. Gene function and pathway enrichment analysis displayed that DEGs and DEPs were significantly enriched in cell wall biosynthesis and lignin biosynthesis. In consistent with genes and proteins expressions in lignin biosynthesis, the contents of lignin monomers precursors were significantly different in IFP and IVP. These results enable us to understand lotus petioles rigidity formation better and provide valuable candidate genes information on further investigation.

Highlights

Plant architecture is the embodiment of space utilization
By analyzing differentially expressed genes (DEGs), DEPs and the abundance of metabolite in the initial floating leaves’ petiole (IFP) and initial vertical leaves’ petiole (IVP), we found that genes highly expressed in IVP in several central biologic processes, such as cell wall biosynthesis, organization, assembly and lignin biosynthesis were associated with lotus petiole rigidity
Many genes involved in cell wall biosynthesis and lignin biosynthesis exhibited differentially expression at both mRNA and protein levels

Summary

Introduction

Plant architecture is the embodiment of space utilization. There are numerous factors contribute to plant architecture including stem height, leaf and branching mode [1]. Several factors such as stem rigidity, branching pattern, and plant height which strongly influences crop yields and efficiency of harvesting have been extensively studied [2,3]. The sacred lotus is a relic aquatic plant with two leaf types, namely the floating leaf and the vertical leaf. Floating leaf petiole exhibits flexibility and floating tendency despite it being longer than the depth of the water, while the vertical leaf petiole is rigid and erect (Figure 1). Stem or petiole rigidity is species-specific and plastic [4] controlled by environmental factors including light, temperature, water and nutrients, among others

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