Key metabolites associated with the onset of flowering of guar genotypes (Cyamopsis tetragonoloba (L.) Taub)

Serafima Arkhimandritova,Alexey Shavarda,Elena Potokina

doi:10.1186/s12870-020-02498-x

Abstract

BackgroundGuar (Cyamopsis tetragonoloba (L.) Taub.), a short-day plant, is an economically valuable legume crop. Seeds of guar serve as a source of galactomannan polysaccharide, known as guar gum, which is in demand in the gas and oil industries. The rapid and complete maturation of guar seeds depends on the flowering time of a particular genotype. It is known that flowering in guar is controlled by several gene systems. However, no information about the process and mechanisms that trigger flowering in guar on the molecular and biochemical levels was previously reported. The aim of the study was to investigate the metabolic landscape underlying transition to the flowering in guar using GC-MS-metabolomic analysis.Results82 diverse guar genotypes (each in 8 replicates) from the VIR collection were grown under experimental conditions of high humidity and long photoperiod. In the stress environment some guar genotypes turned to flowering early (41 ± 1,8 days from the first true leaf appearance) while for others the serious delay of flowering (up to 95 ± 1,7 days) was observed. A total of 244 metabolites were detected by GC-MS analysis on the third true leaves stage of 82 guar genotypes. Among them some molecules were associated with the transition of the guar plants to flowering. Clear discrimination was observed in metabolomic profiles of two groups of «early flowering» and «delayed flowering» plants, with 65 metabolites having a significantly higher abundance in early flowering genotypes. Among them 7 key molecules were identified by S-plot, as potential biomarkers discriminating of «early flowering» and «delayed flowering» guar genotypes.ConclusionsThe metabolomic landscape accompanying transition to flowering in guar was firstly described. The results obtained can be used in subsequent genomic research for identifying metabolite-gene associations and revealing genes responsible for the onset of flowering and photoperiod sensitivity of guar. In addition, the detected key metabolites associated with flowering of guar can be employed as biomarkers allowing rapid screening of breeding material for the potentially early flowering genotypes.

Highlights

Guar (Cyamopsis tetragonoloba (L.) Taub.), a short-day plant, is an economically valuable legume crop
Guar is a short-day legume crop that recently became popular since its seeds serve as is a source of galactomannan polysaccharide, which is used in many industries including gas and oil production
Variation of flowering time among the different guar genotypes at the long photoperiod under greenhouse conditions Guar – is a short day plant, which means that flowering of guar is accelerated by daylight length shorter than the critical photoperiod [3]

Summary

Introduction

Guar (Cyamopsis tetragonoloba (L.) Taub.), a short-day plant, is an economically valuable legume crop. Seeds of guar serve as a source of galactomannan polysaccharide, known as guar gum, which is in demand in the gas and oil industries. The rapid and complete maturation of guar seeds depends on the flowering time of a particular genotype. Guar is a short-day legume crop that recently became popular since its seeds serve as is a source of galactomannan polysaccharide (the guar gum), which is used in many industries including gas and oil production. Besides the determinate and indeterminate growth habits, a particular daylight length significantly affects the onset of flowering in guar [3]. Day-neutral guar genotypes usually mature earlier than those with high sensitivity to the length of photoperiod [4]

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