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Thermal stress induces differential degradation of Rubisco in heat‐sensitive and heat‐tolerant rice
Author(s) -
Bose Anindita,
Tiwari Bs,
Chattopadhyay Manas K,
Gupta Sudhiranjan,
Ghosh Bharati
Publication year - 1999
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.1999.105114.x
Subject(s) - rubisco , thermostability , cultivar , thermolabile , biology , protease , protein degradation , biochemistry , horticulture , enzyme
Degradation of ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco, EC.4.1.1.39), due to elevation in atmospheric temperature, and extent of enzyme damage, due to varietal differences, were studied by [ S]‐methionine pulse‐chase, transcript level of the large subunit (LSU), and protease activity in two rice cultivars. The cultivars N 22 and IR 8 are certified as thermotolerant and thermosensitive, respectively. Differential responses were observed in both cultivars, with the N 22 showing greater thermostability of the Rubisco protein up to 45°C, whereas IR 8 was thermolabile. Elevation of the temperature to 50°C favored the degradation of the protein in both cultivars. The transcript level of the LSU, as studied by Northern blot hybridization, also showed thermostability in N 22, whereas it was thermosensitive in IR 8. Protease activity, as measured by Western blot analysis using purified Rubisco, revealed the same trend in both cultivars and was correlated with protein turnover by [ S]‐methionine and Northern blot analysis. The results indicate that genetic differences exist in two rice cultivars and that the heat‐tolerant cultivar has a protective mechanism against thermal degradation of Rubisco.