Characterization of salt tolerant wheat genotypes by using morpho-physiological, biochemical, and molecular analysis

Ahsan Irshad; Rana Imtiaz Ahmed; Shoaib Ur Rehman; Guozhong Sun; Furqan Ahmad; Muhammad Ali Sher; Muhammad Zahid Aslam; Mohamed M Hassan; Sameer H Qari; Muhammad Kashif Aziz; Zulqurnain Khan

doi:10.3389/fpls.2022.956298

Characterization of salt tolerant wheat genotypes by using morpho-physiological, biochemical, and molecular analysis

Front Plant Sci. 2022 Aug 22:13:956298. doi: 10.3389/fpls.2022.956298. eCollection 2022.

Authors

Ahsan Irshad^{1

2

3}, Rana Imtiaz Ahmed^{2

3}, Shoaib Ur Rehman⁴, Guozhong Sun⁵, Furqan Ahmad⁴, Muhammad Ali Sher⁴, Muhammad Zahid Aslam⁶, Mohamed M Hassan⁷, Sameer H Qari⁷, Muhammad Kashif Aziz^{2

3}, Zulqurnain Khan⁴

Affiliations

¹ National Engineering Laboratory of Crop Molecular Breeding, National Center of Space Mutagenesis for Crop Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
² Regional Agricultural Research Institute, Bahawalpur, Pakistan.
³ Ayub Agricultural Research Institute, Faisalabad, Pakistan.
⁴ SINO-PAK Joint Research Laboratory, Institute of Plant Breeding and Biotechnology, Muhammad Nawaz Sharif University of Agriculture, Multan, Pakistan.
⁵ National Engineering Research Center of Crop Molecular Breeding, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
⁶ Cotton Research Station, Bahawalpur, Pakistan.
⁷ Department of Biology, College of Science, Taif University, Taif, Saudi Arabia.

Abstract

Food security is facing a major threat from salinity and there is a need to develop salt tolerant crop varieties to ensure that the demand for food from the world's increasing population is met. Salinity mostly occurs in arid and semi-arid regions. It may cause many adverse physiological effects on plants, i.e., toxic ion accumulation, disturbed osmotic potential, and decreased crop yield. The present study aimed to investigate the morphological, physiological, biochemical, and genetic parameters of wheat genotypes under salt stress. Six wheat genotypes were screened for salt tolerance at the seedling and maturity stage. Seeds were sown at 0 and 150 mM of salinity level. Biochemical traits, i.e., shoot/root fresh and dry weight, chlorophyll a/b and total chlorophyll contents, shoot nitrogen, shoot phosphorus, proline, and carbohydrates were measured. Wheat genotypes showed a significant increase in free amino acids, shoot nitrogen, and total soluble proteins under saline conditions. Higher Na⁺/K⁺ ratio and free amino acids were estimated under 150 mM NaCl treatment in Pasban-90 and found to be the most salt-tolerant genotype. By contrast, reduced proline, total chlorophyll, and Na⁺/K⁺ ratio were found in Kohistan-97 marking it to be sensitive to stress. Expression analysis of HKTs genes was performed to validate the results of two contrasting genotypes. The differential expression of HKT2; 1 and HKT2; 3 explained the tissue and genotype specific epigenetic variations. Our findings indicated that these selected genotypes can be further used for molecular studies to find out QTLs/genes related to salinity. This suggests that, in contrasting wheat genotypes, there is a differentially induced defense response to salt stress, indicating a functional correlation between salt stress tolerance and differential expression pattern in wheat.

Keywords: expression analysis; high affinity potassium transporters; salt tolerance; sodium chloride; wheat yield.