De novo Transcriptome Analysis in Leymus mollis to Unveil Genes Involved in Salt Stress Response

Wenting Wu,Kai Zhang,Yajing Zhang,Luying Zhu,Yu Gao,Hongxia Zhang

doi:10.32604/phyton.2022.020515

Abstract

Leymus mollis, a wild relative of wheat, is very tolerant to salt stress, and has been considered as a valuable genetic resource for wheat breeding. However, the genetic basis for salt tolerance of this species is still largely unknown. In this study, de novo sequencing, assembly and analysis of L. mollis transcriptome in response to salt stress was performed. A total of 110,323 and 112,846 unigenes were generated for the NaCl-free (CK) and 180 mM NaCl-treated (CT) library, respectively. For the two libraries, 73,414 unigenes were successfully annotated in five common protein databases, and 7521 differentially expressed genes (DEGs) between CK and CT libraries were identified. GO enrichment analysis of the DEGs showed that the significantly enriched GO terms were predominantly involved in environmental adaptation (including “response to abiotic stimulus”, “response to water deprivation”), regulation of signaling pathway (such as “regulation of abscisic acid mediated signaling pathway”, “regulation of cell communication”), and photosynthesis (including “response to light stimulus”, “photosynthesis, light harvesting” and “chlorophyll metabolic process”). KEGG pathway enrichment analysis showed that “mRNA surveillance pathway”, “RNA transport” and “plant hormone signal transduction” were predominantly enriched pathways, followed by several secondary metabolic pathways, photosynthesis, carbohydrate metabolism and lipid metabolism. In addition, DEGs related to osmotic stress, ion homeostasis and oxidative stress, including four dehydrins, five aquaporins, an LmNHX2 and several antioxidant enzymes or proteins genes, were found to be up-regulated in response to salt stress. These results will be helpful for further studies on the molecular mechanisms of salt responses in L. mollis.

Highlights

Soil salinity can severely affect plant growth and development, and reduce crop yield and food production
All these results suggested that the quantity and quality of the sequencing data were good enough for accurate sequence assembly and adequate transcriptome coverage
We found that the Differentially Expressed Genes (DEGs) annotated as “vacuolar Na+/H+ antiporter 2 (NHX2)” was up-regulated, whereas the DEG annotated as “vacuolar protoninorganic pyrophosphatase 1 (AVP1)”, which was considered to provide energy for the activity of the Na+/H+ exchangers (NHXs), was down-regulated, no significant alterations were observed on most NHXs and proton pumps genes at the transcript level after a salt treatment

Summary

Introduction

Soil salinity can severely affect plant growth and development, and reduce crop yield and food production. More than 6% of lands throughout the world are affected by salinity [1]. Improving the resistance of crops to salt stress and the utilization efficiency of salty land have become one of the most important objectives for crop breeders. Increased soil salt concentration first causes osmotic stress which instantly affects plant growth. Osmotic stress and ion toxicity often cause oxidative stress and a series of secondary stresses. These harmful effects caused by salt stress inhibit plant growth and productivity in various ways, including impairing physiological and biochemical metabolic processes, decreasing photosynthetic efficiency and causing nutritional disorders in plants [3,4]

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Results

Discussion

Conclusion