TY - JOUR

T1 - Evaluation of wheat mutants for thermo-stability through physiological parameters

AU - Khattak, G. S S

AU - Parry, M. A J

AU - Andralojc, P. J.

AU - Srinives, P.

AU - Saeed, I.

PY - 2014

Y1 - 2014

N2 - Photosynthetic activity performance of 3 wheat mutants such as BG48-3-1, BG48-3-7, and BD29-3-9 were studied at 2 different levels of temperature (20 °C and 30 °C) at seedling stage under controlled environment conditions during 2011 at Rothamsted Research, UK. These mutants had earlier been developed from 'Cham1' by exposing germinating seeds to the chemical mutagen, ethyl methane sulphonate (EMS). Simple mutations affecting amino acid residues close to catalytically important regions of Rubisco Activase in these mutants were identified through TILLING (Targeting Induced Local Lesions in Genomes). Although generally the mutants were less active for photosynthetic activity (A) than 'Cham1' (control) at 20 °C but their A exceeded those of the control at every CO2 concentration and photosynthetic photon flux density (PPFD) tested at 30 °C. The higher A of the mutant lines at 30 °C was correlated with the induction of mutations affecting amino acid residues close to catalytically important regions of Rubisco activase. Differing trends in leaf stomatal conductance (gs) were observed for mutants and parent lines at 20 °C and 30 °C. Among the mutants, those with gs below 0.54 mmol m-2 s-1 at 20 °C showed greater gs at 30 °C; while the mutants exceeding the gs above 0.54 mmol m-2 s-1 at 20 °C showed slightly lower gs at 30 °C. In Cham1, however, the gs was invariably higher at 30 °C than 20 °C. Intercellular CO2 (Ci) was slightly lower in all mutant lines at every CO2 concentration and at all light intensities. Ci was also slightly lower in mutants at lowest light intensities at 20 than 30 °C. In contrast, Cham1 showed modest increase in Ci at 30 °C. Mutant BG48-3-1 at 30 °C displayed the highest rates of transpiration (E), while Cham1 and mutant BG48-3-7 at 20 °C displayed the highest E. The results are consistent with Rubisco activase from the mutant lines possessing greater thermal-stability than parent 'Cham1' at 30 °C under different levels of CO2 and PPFD. However, the mutant lines require more thorough evaluation before recommendation as a source of germplasm with enhanced thermal tolerance for use in wheat breeding programs.

AB - Photosynthetic activity performance of 3 wheat mutants such as BG48-3-1, BG48-3-7, and BD29-3-9 were studied at 2 different levels of temperature (20 °C and 30 °C) at seedling stage under controlled environment conditions during 2011 at Rothamsted Research, UK. These mutants had earlier been developed from 'Cham1' by exposing germinating seeds to the chemical mutagen, ethyl methane sulphonate (EMS). Simple mutations affecting amino acid residues close to catalytically important regions of Rubisco Activase in these mutants were identified through TILLING (Targeting Induced Local Lesions in Genomes). Although generally the mutants were less active for photosynthetic activity (A) than 'Cham1' (control) at 20 °C but their A exceeded those of the control at every CO2 concentration and photosynthetic photon flux density (PPFD) tested at 30 °C. The higher A of the mutant lines at 30 °C was correlated with the induction of mutations affecting amino acid residues close to catalytically important regions of Rubisco activase. Differing trends in leaf stomatal conductance (gs) were observed for mutants and parent lines at 20 °C and 30 °C. Among the mutants, those with gs below 0.54 mmol m-2 s-1 at 20 °C showed greater gs at 30 °C; while the mutants exceeding the gs above 0.54 mmol m-2 s-1 at 20 °C showed slightly lower gs at 30 °C. In Cham1, however, the gs was invariably higher at 30 °C than 20 °C. Intercellular CO2 (Ci) was slightly lower in all mutant lines at every CO2 concentration and at all light intensities. Ci was also slightly lower in mutants at lowest light intensities at 20 than 30 °C. In contrast, Cham1 showed modest increase in Ci at 30 °C. Mutant BG48-3-1 at 30 °C displayed the highest rates of transpiration (E), while Cham1 and mutant BG48-3-7 at 20 °C displayed the highest E. The results are consistent with Rubisco activase from the mutant lines possessing greater thermal-stability than parent 'Cham1' at 30 °C under different levels of CO2 and PPFD. However, the mutant lines require more thorough evaluation before recommendation as a source of germplasm with enhanced thermal tolerance for use in wheat breeding programs.

KW - Mutants

KW - Photosynthesis

KW - Rubisco

KW - Thermo-stability

KW - Transpiration

KW - Wheat

UR - http://www.scopus.com/inward/record.url?scp=84902379735&partnerID=8YFLogxK

M3 - Journal article

AN - SCOPUS:84902379735

VL - 46

SP - 112

EP - 119

JO - Sabrao Journal of Breeding and Genetics

JF - Sabrao Journal of Breeding and Genetics

SN - 1029-7073

IS - 1

ER -