DIA-Based Quantitative Proteomics Reveals the Protein Regulatory Networks of Floral Thermogenesis in Nelumbo nucifera.

Yueyang Sun,Qian Li,Hao Chen,Yu Zou,Zeyang Xiong,Qinru Zi,Jing Jin,Ying Wang,Zhiying Liu,Jing Peng,Yi Ding

doi:10.3390/ijms22158251

Abstract

The sacred lotus (Nelumbo nucifera) can maintain a stable floral chamber temperature between 30 and 35 °C when blooming despite fluctuations in ambient temperatures between about 8 and 45 °C, but the regulatory mechanism of floral thermogenesis remains unclear. Here, we obtained comprehensive protein profiles from receptacle tissue at five developmental stages using data-independent acquisition (DIA)-based quantitative proteomics technology to reveal the molecular basis of floral thermogenesis of N. nucifera. A total of 6913 proteins were identified and quantified, of which 3513 differentially abundant proteins (DAPs) were screened. Among them, 640 highly abundant proteins during the thermogenic stages were mainly involved in carbon metabolism processes such as the tricarboxylic acid (TCA) cycle. Citrate synthase was identified as the most connected protein in the protein-protein interaction (PPI) network. Next, the content of alternative oxidase (AOX) and plant uncoupling protein (pUCP) in different tissues indicated that AOX was specifically abundant in the receptacles. Subsequently, a protein module highly related to the thermogenic phenotype was identified by the weighted gene co-expression network analysis (WGCNA). In summary, the regulation mechanism of floral thermogenesis in N. nucifera involves complex regulatory networks, including TCA cycle metabolism, starch and sucrose metabolism, fatty acid degradation, and ubiquinone synthesis, etc.

Highlights

Body heat production is generally considered to occur in homeothermic animals, which can adapt to changes in environmental temperature through thermoregulation [1]
We provided comprehensive protein profiles from receptacle tissue using data-independent acquisition (DIA)-based quantitative proteomics technology to further reveal the molecular basis of floral thermogenesis in N. nucifera
The DIA data with the spectra library were analyzed by Spectronaut Pulsar 11.0 (Biognosys AG, Switzerland), and the results showed that 6913 proteins were further quantified (Table S2)

Summary

Introduction

Body heat production is generally considered to occur in homeothermic animals, which can adapt to changes in environmental temperature through thermoregulation [1]. Similar thermogenesis has been found and described in the floral organs of some flowering plants, including Araceae [2,3,4,5], Nelumbonaceae [6], Nymphaeaceae [7], Magnoliaceae [8], Cycadaceae [9], and so on. The appropriate temperature generated by thermogenesis contributes to the prevention of the flower organs from suffering low temperatures [3], promoting the success of double fertilization [10], facilitating pollen germination and pollen tube growth [11], and attracting insect pollinators by emitting odors and providing heat rewards [12,13]. The AOX activity is related to thermogenesis, which can characterize the capacity of the alternative pathway and increases in thermogenic tissue when thermogenesis occurs [18,19]. The increased AOX activity was detected during the thermogenic stages in Nelumbo nucifera, while it returned to the initial level when thermogenesis ended [20]

Methods

Results

Discussion

Conclusion