The role of salicylic acid in modulating phenotyping in spring wheat varieties for mitigating drought stress

Abstract

Climate change-related droughts that recur frequently are one of the biggest obstacles to wheat (Triticum aestivum L.) productivity. Worldwide, attempts are being done to establish drought-resistant cultivars. However, progress is slow since drought tolerance is a complex trait controlled by numerous genes, and its expression is influenced by the environment. Phenotypic, biochemical physiological, and genotyping approaches are highlighted as critical research components for leveraging genetic variation in eight wheat genotypes. Treatments included eight spring wheat genotypes (IPK_040, IPK_046, IPK_050, IPK_071, IPK_105, WAS_007, WAS_024 and WAS_031), normal irrigation (NI), drought stress (D) (30% field capacity (FC)), normal irrigation with 0.5 mM SA (NSA), and drought treated with SA (DSA). The results revealed that there was a reduction in relative water content, an increase membrane leakage, and leaf chlorophyll content under drought stress. SA induced the defense responses against drought by increasing the osmolytes and the antioxidative enzymes activities. Compared to the NI group, the DSA treatment improved the water regulation, antioxidant capacity, and drought stress resistance. SA significantly reduced the deleterious effects of water stress on phenotyping more in WAS_ 024 and IPK_ 105 genotypes. The most responsive genotypes to salicylic acid were IPK_ 046 among the IPK genotypes, whereas WAS_031 genotype was amongst WAS genotypes based on the morpho-physiological traits. The findings of this study give a solid foundation for assessing drought resistance in T. aestivum and developing cultivation-specific water management methods.

Keywords: Triticum aestivum; Heritability; Phenotyping; Salicylic acid; Water- deficit tolerance.

Fig. 1

Cell plot of nine quantitative morphological traits of 45 DAS eight spring Triticum aestivum under different treatments (D, drought; DSA, drought with salicylic acid; NI, normal irrigation and NSA, normal irrigation with salicylic acid). Abbreviations: FW (fresh weight); DW (dry weight); ShL (shoot length); RW (root width); LA (leaf area); No. L (No. of leaves) and No. R (No. of roots). The red colour indicated the highest values, the green colour indicated moderate values and the blue one indicated the lowest one)

Fig. 2

Biplot matrix illustrating the distribution of 45 DAS eight T. aestivum, PC1 and PC2 components based on the analysis of morphological traits under different treatments (D, drought; DSA, drought with salicylic acid; NI, normal irrigation and NSA, normal irrigation with salicylic acid). The dots were eight wheat genotypes under different treatments, and the vectors (red arrows) were nine quantitative morphological traits. The abbreviations were previously mentioned in the earlier figures

Fig. 3

Cell plot of 10 physiological and biochemical traits of 45 DAS eight spring T. aestivum under different treatments (D, drought; DSA, drought with salicylic acid; NI, normal irrigation and NSA, normal irrigation with salicylic acid). Abbreviations: WC (water content); ML (membrane leakage); LG (leaf greenness); Carb (carbohydrates); ProT (protein); ProL (proline); CAT (catalase); POX (peroxidase) and PPO (polyphenol oxidase). The orange colour indicated the highest values, while the blue colour showed the lowest ones)

Fig. 4

Partial correlation diagram of 10 physiological and biochemical traits of 45 DAS eight spring T. aestivum under different treatments (D, drought; DSA, drought with salicylic acid; NI, normal irrigation and NSA, normal irrigation with salicylic acid). Orange colour indicates positive correlation, blue colour indicates the negative correlation, while the thickness of lines indicates the strength of the correlation (see scale at the above right corner)

Fig. 5

Constellation plot of 10 physiological and biochemical traits of 45 DAS eight spring T. aestivum under different treatments (D, drought; DSA, drought with salicylic acid; NI, normal irrigation and NSA, normal irrigation with salicylic acid)

Fig. 6

Principal component analysis (PCA), A the score plot, B biplot and C Partial correlation diagram of all 19 combined data (morphological, physiological and biochemical traits) of 45 DAS eight spring T. aestivum under different treatments (D, drought; DSA, drought with salicylic acid; NI, normal irrigation and NSA, normal irrigation with salicylic acid). The dashed blue, green and red circles represented the distribution of the genotypes under different conditions. Correlation levels are ranged from blue for negative correlation, green intermediate to red for positive one, while the thickness of lines indicates the strength of the correlation. Abbreviations: FW (fresh weight); DW (dry weight); ShL (shoot length); RW (root width); LA (leaf area); No. L (No. of leaves); No. R (No. of roots); WC (water content); ML (membrane leakage); LG (leaf greenness); Carb (carbohydrates); ProT ( protein); ProL (proline); CAT (catalase); POX ( peroxidase), and PPO (polyphenol oxidase)

Fig. 7

Two-way clustering using hierarchical co-clustering dendrogram and heatmap; row clusters were obtained at genotype level, whereas the column cluster were recorded at trait of all 19 combined data (morphological, physiological and biochemical traits) of 45 DAS eight spring T. aestivum under different treatments (D, drought; DSA, drought with salicylic acid; NI, normal irrigation and NSA, normal irrigation with salicylic acid). Correlation levels are colored by red for positive correlation and blue for negative one