JOURNAL ARTICLE

Can the cold tolerance of C4 photosynthesis in Miscanthus x giganteus relative to Zea mays be explained by differences in activities and thermal properties of Rubisco?

Dafu Wang, Shawna L Naidu, Archie R Portis, Stephen P Moose, Stephen P Long
Journal of Experimental Botany 2008, 59 (7): 1779-87
18503044
The previous investigations show that the amount and activity of Rubisco appears the major limitation to effective C(4) photosynthesis at low temperatures. The chilling-tolerant and bioenergy feedstock species Miscanthus x giganteus (M. x giganteus) is exceptionally productive among C(4) grasses in cold climates. It is able to develop photosynthetically active leaves at temperatures 6 degrees C below the minimum for maize, and achieves a productivity even at 52 degrees N that exceeds that of the most productive C(3) crops at this latitude. This study investigates whether this unusual low temperature tolerance can be attributed to differences in the amount or kinetic properties of Rubisco relative to maize. An efficient protocol was developed to purify large amounts of functional Rubisco from C(4) leaves. The maximum carboxylation activities (V(max)), activation states, catalytic rates per active site (K(cat)) and activation energies (E(a)) of purified Rubisco and Rubisco in crude leaf extracts were determined for M. x giganteus grown at 14 degrees C and 25 degrees C, and maize grown at 25 degrees C. The sequences of M. x giganteus Rubisco small subunit mRNA are highly conserved, and 91% identical to those of maize. Although there were a few differences between the species in the translated protein sequences, there were no significant differences in the catalytic properties (V(max), K(cat), and E(a)) for purified Rubisco, nor was there any effect of growth temperature in M. x giganteus on these kinetic properties. Extracted activities were close to the observed rates of CO(2) assimilation by the leaves in vivo. On a leaf area basis the extracted activities and activation state of Rubisco did not differ significantly, either between the two species or between growth temperatures. The activation state of Rubisco in leaf extracts showed no significant difference between warm and cold-grown M. x giganteus. In total, these results suggest that the ability of M. x giganteus to be productive and maintain photosynthetically competent leaves at low temperature does not result from low temperature acclimation or adaptation of the catalytic properties of Rubisco.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
18503044
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"