Characterization of Rubisco activase from thermally contrasting genotypes of Acer rubrum (Aceraceae).
نویسندگان
چکیده
The lability of Rubisco activase function is thought to have a major role in the decline of leaf photosynthesis under moderate heat (<35°C). To investigate this further, we characterized Rubisco activase and explored its role in the previously demonstrated thermal acclimation and inhibition of two genotypes of Acer rubrum originally collected from Florida (FL) and Minnesota (MN). When plants were grown at 33/25°C (day/night) for 21 d, the FL genotype compared to the MN genotype maintained about a two-fold increase in leaf photosynthetic rates at 33-42°C and had a 22% increase in the maximal rate of Rubisco carboxylation (V(cmax)) at 33°C under nonphotorespiratory conditions. Both genotypes had two leaf Rca transcripts, likely from equivalent alternative splicing events. The RCA1 and RCA2 proteins increased modestly in FL plants under warmer temperature, while only RCA2 protein increased in MN plants. Rubisco large subunit (RbsL) protein abundance was relatively unaffected in either genotype by temperature. These results support the idea that Rubisco activase, particularly the ratio of Rubisco activase to Rubisco, may play a role in the photosynthetic heat acclimation in A. rubrum and may have adaptive significance. This mechanism alone is not likely to entirely explain the thermotolerance in the FL genotype, and future research on adaptive mechanisms to high temperatures should consider activase function in a multipathway framework.
منابع مشابه
Inhibition and acclimation of C(3) photosynthesis to moderate heat: a perspective from thermally contrasting genotypes of Acer rubrum (red maple).
Effects of moderate heat on growth and photosynthesis were investigated in two clonal genotypes of Acer rubrum L., originally collected from the thermally contrasting habitats of Florida and Minnesota, USA, and known in the horticultural trade for sensitivity and insensitivity to heat, respectively. Under both common garden and warm greenhouse conditions (day/night temperature of 33/25 degrees ...
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متن کاملSummary Effects of moderate heat on growth and photosyn- thesis were investigated in two clonal genotypes of Acer rub-
thesis were investigated in two clonal genotypes of Acer rubrum L., originally collected from the thermally contrasting habitats of Florida and Minnesota, USA, and known in the horticultural trade for sensitivity and insensitivity to heat, respectively. Under both common garden and warm greenhouse conditions (day/night temperature of 33/25 °C), the Florida genotype exhibited more growth than th...
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عنوان ژورنال:
- American journal of botany
دوره 94 6 شماره
صفحات -
تاریخ انتشار 2007