# Analyzing the Specificity of KAWLR Genetic Resources in Afghan Landrace Wheat for Ca-Rich High pH Soil Tolerance Using Proteomics

## TL;DR

This study explores how Afghan wheat landraces adapt to high calcium and alkaline soils, identifying root-based traits and proteomic responses that could aid in breeding resilient wheat varieties.

## Contribution

The study introduces a semi-hydroponic screening method and identifies proteomic markers for stress adaptation in Afghan wheat under calcareous-alkaline conditions.

## Key findings

- Winter-type KAWLR wheat shows greater root allocation and rhizosphere pH stability under stress.
- Proteomic analysis reveals a global downshift in metabolic activity but preservation of root growth machinery.
- Specific proteins related to energy transport and cell growth increase under stress conditions.

## Abstract

Breeding wheat varieties that are resilient to arid climates, which impart a complex combination of stresses, including excessive Ca, high pH, nutrient deficiency, and aridity, is important. Afghan landrace wheat is assumed to have evolved with a specific prototypical pattern of traits to adapt to its challenging, composite stress environment. Here, a useful semi-hydroponic double cup screen aiding proteomic analysis was exploited to reconstruct the combined excessive Ca2+ (100 ppm) and extreme pH (11.0) of the soils and to dissect specific morpho-physiological characteristics and adaptation strategies in Kihara Afghan wheat landrace (KAWLR). When compared to other cultivars and growth habits, several winter-type KAWLR showed lower unused N-K-P and greater rhizosphere pH stability in the bottom cup and higher tolerance in terms of greater root allocation shift, and most of their above ground traits (shoot biomass, chlorophyll content, and stomatal conductance) were strongly correlated with root length and biomass under stress conditions. Quantitative proteomics on the roots of a tolerant winter-type KAWLR, Herat-740 (KU-7449), showed a strong decreasing trend in changed proteins (12 increased/816 decreased). The proteins (such as mitochondrial phosphate carrier protein, cytoskeleton-related α-, and β-tubulin) that increased in abundance were associated with energy transport and cell growth. A metabolism overview revealed that most proteins that were mapped to glycolysis, fermentation, and the TCA cycle decreased in abundance. However, proteins related to cell wall and lipid metabolism pathways remained unchanged. Our results suggest that winter-type KAWLR adopts a homeostatic stress adaptation strategy that globally downshifts metabolic activity, while selectively maintaining root growth machinery. Root allocation shift, rhizosphere pH stabilization (nutrient solubilization), and a selective proteome response maintaining the root growth machinery in winter-type KAWLR could be breeding selection markers for early-stage screening in calcareous-alkaline arid land.