Systematic biology analysis on photosynthetic carbon metabolism of maize leaf following sudden heat shock under elevated CO2

Mingnan Qu,James A Bunce,Richard C Sicher,Genyun Chen,Xiaocen Zhu

doi:10.1038/s41598-018-26283-x

Abstract

Plants would experience more complex environments, such as sudden heat shock (SHS) stress combined with elevated CO2 in the future, and might adapt to this stressful condition by optimizing photosynthetic carbon metabolism (PCM). It is interesting to understand whether this acclimation process would be altered in different genotypes of maize under elevated CO2, and which metabolites represent key indicators reflecting the photosynthetic rates (PN) following SHS. Although B76 had greater reduction in PN during SHS treatment, our results indicated that PN in genotype B76, displayed faster recovery after SHS treatment under elevated CO2 than in genotype B106. Furthermore, we employed a stepwise feature extraction approach by partial linear regression model. Our findings demonstrated that 9 key metabolites over the total (35 metabolites) can largely explain the variance of PN during recovery from SHS across two maize genotypes and two CO2 grown conditions. Of these key metabolites, malate, valine, isoleucine, glucose and starch are positively correlated with recovery pattern of PN. Malate metabolites responses to SHS were further discussed by incorporating with the activities and gene expression of three C4 photosynthesis-related key enzymes. We highlighted the importance of malate metabolism during photosynthesis recovery from short-term SHS, and data integration analysis to better comprehend the regulatory framework of PCM in response to abiotic stress.

Highlights

Increasing atmospheric CO2 concentration has led to higher surface temperatures[1]
Photosynthetic efficiency (PN) is an essential indicator reflecting growth status in response to heat stress, and previous studies have shown that the recovery of photosynthetic rates (PN) in plants from sudden heat shock (SHS) is related to ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activase, Oxygen evolving complex (OEC), protein contents of stroma and the thylakoid membrane and the photochemical efficiency of photosystem II4–7
The PN in B76 following a 2 h sudden heat shock (SHS) treatment decreased by averaged 62% across two CO2 growth conditions, the reduction of which was twice more than that observed in B106 (Fig. 2a,b)

Summary

Introduction

Two different types of temperature stress are known: an increase in the mean temperature and an increase in the frequency of sudden heat shock (SHS)[2]. This SHS can trigger dramatically detrimental effects on crop growth and final yield[3]. Heat stress can induce the changes of various metabolites such as organic acids, amino acids and carbohydrates, which have important functions involved in photosynthesis and respiration[9] These compounds are involved in various metabolic functions within the plant such as regulating plant-water relations, signaling pathways, and the protein synthesis as well as defense systems against stress[10].

Methods

Results

Conclusion