Transcriptomic and metabolomic analysis reveals the role of CoA in the salt tolerance of Zygophyllum spp

Jie Wang,Xi Jiang,Chufeng Zhao,Zhongming Fang,Peipei Jiao

doi:10.1186/s12870-019-2226-8

Abstract

BackgroundZygophyllum is an important medicinal plant, with notable properties such as resistance to salt, alkali, and drought, as well as tolerance of poor soils and shifting sand. However, the response mechanism of Zygophyllum spp. to abiotic stess were rarely studied.ResultsHere, we aimed to explore the salt-tolerance genes of Zygophyllum plants by transcriptomic and metabolic approaches. We chose Z. brachypterum, Z. obliquum and Z. fabago to screen for salt tolerant and sensitive species. Cytological observation showed that both the stem and leaf of Z. brachypterum were significantly thicker than those of Z. fabago. Then, we treated these three species with different concentrations of NaCl, and found that Z. brachypterum exhibited the highest salt tolerance (ST), while Z. fabago was the most sensitive to salt (SS). With the increase of salt concentration, the CAT, SOD and POD activity, as well as proline and chlorophyll content in SS decreased significantly more than in ST. After salt treatment, the proportion of open stomata in ST decreased significantly more than in SS, although there was no significant difference in stomatal number between the two species. Transcriptomic analysis identified a total of 11 overlapping differentially expressed genes (DEGs) in the leaves and roots of the ST and SS species after salt stress. Two branched-chain-amino-acid aminotransferase (BCAT) genes among the 11 DEGs, which were significantly enriched in pantothenate and CoA biosynthesis, as well as the valine, leucine and isoleucine biosynthesis pathways, were confirmed to be significantly induced by salt stress through qRT-PCR. Furthermore, overlapping differentially abundant metabolites showed that the pantothenate and CoA biosynthesis pathways were significantly enriched after salt stress, which was consistent with the KEGG pathways enriched according to transcriptomics.ConclusionsIn our study, transcriptomic and metabolomic analysis revealed that BCAT genes may affect the pantothenate and CoA biosynthesis pathway to regulate the salt tolerance of Zygophyllum species, which may constitute a newly identified signaling pathway through which plants respond to salt stress.

Highlights

Zygophyllum is an important medicinal plant, with notable properties such as resistance to salt, alkali, and drought, as well as tolerance of poor soils and shifting sand
The results demonstrated that the pith area of the main stem of Z. brachypterum was the largest of the three species, while that of Z. fabago was the smallest (Fig. 1a-c)
These results indicated that Z. brachypterum plants might have a higher capacity to transport water from the stems and store it in the leaves than Z. fabago

Summary

Introduction

Zygophyllum is an important medicinal plant, with notable properties such as resistance to salt, alkali, and drought, as well as tolerance of poor soils and shifting sand. Increasing numbers of studies have elucidated the salt stress signal transduction pathways of plants, which are important for the comprehensive understanding of the molecular mechanisms of plant salt tolerance. The salt overly sensitive (SOS) signaling pathway is responsible for Na+ excretion in plant root cells, which is one of the best-studied mechanisms of plant salt tolerance. In this pathway, three SOS genes (SOS1, SOS2 and SOS3) are involved in mediating the signals that regulate the intracellular ion balance [19,20,21,22]

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