Transcriptome and Metabolome Analysis Reveals Salt-Tolerance Pathways in the Leaves and Roots of ZM-4 (<i>Malus zumi</i>) in the Early Stages of Salt Stress
The breeding of salt-tolerant rootstock relies heavily on the availability of salt-tolerant <i>Malus</i> germplasm resources. The first step in developing salt-tolerant resources is to learn their molecular and metabolic underpinnings. Hydroponic seedlings of both ZM-4 (salt-tolerant res...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2023-02-01
|
| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/24/4/3638 |
| Summary: | The breeding of salt-tolerant rootstock relies heavily on the availability of salt-tolerant <i>Malus</i> germplasm resources. The first step in developing salt-tolerant resources is to learn their molecular and metabolic underpinnings. Hydroponic seedlings of both ZM-4 (salt-tolerant resource) and M9T337 (salt-sensitive rootstock) were treated with a solution of 75 mM salinity. ZM-4’s fresh weight increased, then decreased, and then increased again after being treated with NaCl, whereas M9T337′s fresh weight continued to decrease. The results of transcriptome and metabolome after 0 h (CK) and 24 h of NaCl treatment showed that the leaves of ZM-4 had a higher content of flavonoids (phloretinm, naringenin-7-O-glucoside, kaempferol-3-O-galactoside, epiafzelechin, etc.) and the genes (<i>CHI</i>, <i>CYP</i>, <i>FLS</i>, <i>LAR</i>, and <i>ANR</i>) related to the flavonoid synthesis pathway showed up-regulation, suggesting a high antioxidant capacity. In addition to the high polyphenol content (L-phenylalanine, 5-O-p-coumaroyl quinic acid) and the high related gene expression (<i>4CLL9</i> and <i>SAT</i>), the roots of ZM-4 exhibited a high osmotic adjustment ability. Under normal growing conditions, the roots of ZM-4 contained a higher content of some amino acids (L-proline, tran-4-hydroxy-L-prolin, L-glutamine, etc.) and sugars (D−fructose 6−phosphate, D−glucose 6−phosphate, etc.), and the genes (<i>GLT1</i>, <i>BAM7</i>, <i>INV1</i>, etc.) related to these two pathways were highly expressed. Furthermore, some amino acids (S-(methyl) glutathione, N-methyl-trans-4-hydroxy-L-proline, etc.) and sugars (D-sucrose, maltotriose, etc.) increased and genes (<i>ALD1</i>, <i>BCAT1</i>, <i>AMY1.1</i>, etc.) related to the pathways showed up-regulation under salt stress. This research provided theoretical support for the application of breeding salt-tolerant rootstocks by elucidating the molecular and metabolic mechanisms of salt tolerance during the early stages of salt treatment for ZM-4. |
|---|---|
| ISSN: | 1661-6596 1422-0067 |