Comparative Proteomic Analysis of Tolerant and Sensitive Varieties Reveals That Phenylpropanoid Biosynthesis Contributes to Salt Tolerance in Mulberry.

Tiantian Gan,Chao Su,Xiaopeng Cui,Minjuan Zhang,Tian Hui,Yonghua Qian,Lijun Bao,Ziwei Lin,Feng Jiao,Yanzhen Huang,Hexin Wang

doi:10.3390/ijms22179402

Abstract

Mulberry, an important woody tree, has strong tolerance to environmental stresses, including salinity, drought, and heavy metal stress. However, the current research on mulberry resistance focuses mainly on the selection of resistant resources and the determination of physiological indicators. In order to clarify the molecular mechanism of salt tolerance in mulberry, the physiological changes and proteomic profiles were comprehensively analyzed in salt-tolerant (Jisang3) and salt-sensitive (Guisangyou12) mulberry varieties. After salt treatment, the malondialdehyde (MDA) content and proline content were significantly increased compared to control, and the MDA and proline content in G12 was significantly lower than in Jisang3 under salt stress. The calcium content was significantly reduced in the salt-sensitive mulberry varieties Guisangyou12 (G12), while sodium content was significantly increased in both mulberry varieties. Although the Jisang3 is salt-tolerant, salt stress caused more reductions of photosynthetic rate in Jisang3 than Guisangyou12. Using tandem mass tags (TMT)-based proteomics, the changes of mulberry proteome levels were analyzed in salt-tolerant and salt-sensitive mulberry varieties under salt stress. Combined with GO and KEGG databases, the differentially expressed proteins were significantly enriched in the GO terms of amino acid transport and metabolism and posttranslational modification, protein turnover up-classified in Guisangyou12 while down-classified in Jisang3. Through the comparison of proteomic level, we identified the phenylpropanoid biosynthesis may play an important role in salt tolerance of mulberry. We clarified the molecular mechanism of mulberry salt tolerance, which is of great significance for the selection of excellent candidate genes for saline-alkali soil management and mulberry stress resistance genetic engineering.

Highlights

Plants need to adapt with the constantly changing environment, including frequent stress environments like drought, salinity, chilling, cold, and heavy metal stress that are not conducive to plant growth and development
One Differentially Regulated Proteins (DRPs) shared between the two varieties. These results indicated that the salt-sensitive mulberry variety and salt-tolerant mulberry variety have different protein profiles in response to salt stress
These results suggest that phenylpropanoid biosynthesis may contribute to salt tolerance in mulberry

Summary

Introduction

Plants need to adapt with the constantly changing environment, including frequent stress environments like drought, salinity, chilling, cold, and heavy metal stress that are not conducive to plant growth and development. Water deficit and high salinity induced osmotic stress severely restricts plant growth and productivity. Salinity has caused great loss to crop production around the world [4]. Salt stress disrupts many physiological and biochemical processes in plant cell and induces iron toxicity, osmotic stress, and nutritional deficiencies [5]. Plants evolved to survive in adverse environmental stresses through a variety of strategies, such as developing serious sensors and signaling pathways, stress induced organelles (chloroplasts, mitochondria, peroxisomes, nuclei, and cell walls) response. A series of physiological processes including the synthesis of osmolytes (e.g., proline, glutathione, mannitol, carbohydrate, glycine betaine, and polyamines) and the activation of antioxidant enzymes (e.g., catalase, glutathione peroxidase, superoxide dismutase, and peroxidase) enhance the tolerance to salt stress [6,7]

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Conclusion