Maize metabolome and proteome responses to controlled cold stress partly mimic early-sowing effects in the field and differ from those of Arabidopsis.

Maria Urrutia,Thierry Balliau,Yves Gibon,Catherine Giauffret,Mélisande Blein‐Nicolas,Stéphane Bernillon,Daniel Jacob,Mickaël Maucourt,Hélène Sellier,Patricia Ballias,Camille Bénard,Michel Zivy,Annick Moing,Catherine Deborde,Sylvain Prigent

doi:10.1111/pce.13993

Abstract

In Northern Europe, sowing maize one‐month earlier than current agricultural practices may lead to moderate chilling damage. However, studies of the metabolic responses to low, non‐freezing, temperatures remain scarce. Here, genetically‐diverse maize hybrids (Zea mays, dent inbred lines crossed with a flint inbred line) were cultivated in a growth chamber at optimal temperature and then three decreasing temperatures for 2 days each, as well as in the field. Leaf metabolomic and proteomic profiles were determined. In the growth chamber, 50% of metabolites and 18% of proteins changed between 20 and 16°C. These maize responses, partly differing from those of Arabidopsis to short‐term chilling, were mapped on genome‐wide metabolic maps. Several metabolites and proteins showed similar variation for all temperature decreases: seven MS‐based metabolite signatures and two proteins involved in photosynthesis decreased continuously. Several increasing metabolites or proteins in the growth‐chamber chilling conditions showed similar trends in the early‐sowing field experiment, including trans‐aconitate, three hydroxycinnamate derivatives, a benzoxazinoid, a sucrose synthase, lethal leaf‐spot 1 protein, an allene oxide synthase, several glutathione transferases and peroxidases. Hybrid groups based on field biomass were used to search for the metabolite or protein responses differentiating them in growth‐chamber conditions, which could be of interest for breeding.

Highlights

Temperature is a crucial factor for plant crop development from germination to harvest and for productivity, especially for cereals which are major sources of human food and animal feed
Two of the three metabolites that were down-regulated by chilling in the growth chamber were downregulated in response to early sowing in the field
We found that nitrate reductase and ferredoxin-nitrite reductase protein relative contents were strongly decreased, in agreement with the decreased nitrogen assimilation observed in response to chilling in several species including maize (Schlüter et al, 2013)

Summary

| INTRODUCTION

Temperature is a crucial factor for plant crop development from germination to harvest and for productivity, especially for cereals which are major sources of human food and animal feed. Liquid chromatography coupled with mass spectrometry (LC–MS) of semi-polar extracts provides information about specialized metabolites, for example, flavonoids, hydroxycinnamates and benzoxazinoids Such analytical approaches have been applied widely to cereals (Balmer, Flors, Glauser, & Mauch-Mani, 2013; Gálvez, 2020; Khakimov, Bak, & Engelsen, 2014; Saia, Fragasso, De Vita, & Beleggia, 2019), including maize for studies on environmental effects (Sun et al, 2016; Tang et al, 2017). The present study used untargeted metabolomic and proteomic approaches on a collection of genetically diverse maize hybrids cultivated in a growth chamber and in the field It aimed at deciphering the molecular mechanisms involved in the response to progressively decreasing temperatures at the vegetative stage and identifying metabolic responses that could be extrapolated from growth-chamber conditions to early sowing in the field. According to their biomass in the field to search for the metabolite, metabolite signature or protein responses differentiating them in growth-chamber conditions, and which could be of potential interest for proposing ideotypes and breeding purposes

| MATERIALS AND METHODS

| RESULTS

| DISCUSSION

Findings

| CONCLUSION