Aluminum stress and protein synthesis in near isogenic lines of Triticum aestivum differing in aluminum tolerance

Abstract

Aluminum (Al) stress was examined in three lines of wheat (Triticum aestivum L.) by measuring root lengths, protein synthesis and protein accumulation in seedling root tips grown in a hydroponic system. An Al‐sensitive, recurrent wheat parent (cv. Katepwa) showed very little root growth in low Al concentrations. In contrast, an Al‐tolerant near isogenic line (Alikat) and Al‐tolerant donor (cv. Maringa) had much greater root growth. Segregation data from an F2 population (Katepwa × Alikat) showed that one major gene controlled Al tolerance based on root growth (X2= 0.651). All three lines showed an approximately 2‐fold increase in [35S]‐Met incorporation in root tips after 3 days in Al and a comparable increase in root‐tip dry weight. Maringa and Alikat root tips showed an increased total protein content while Katepwa root tips showed no increase in total protein content during the Al stress. Based on higher specific activities, insoluble proteins were preferentially translated in all three lines during Al stress. Proteinase activity in Katepwa root tips was 1.7‐fold higher during Al stress, with Maringa and Alikat showing no change in proteinase activity. The Al‐induced, increased proteinase activity in Katepwa appeared to inhibit soluble protein accumulation.