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Title: Increased activity of core photorespiratory enzymes and CO2 transfer conductances are associated with higher and more optimal photosynthetic rates under elevated temperatures in the extremophile Rhazya stricta
Abstract

Increase photorespiration and optimising intrinsic water use efficiency are unique challenges to photosynthetic carbon fixation at elevated temperatures. To determine how plants can adapt to facilitate high rates of photorespiration at elevated temperatures while also maintaining water‐use efficiency, we performed in‐depth gas exchange and biochemical assays of the C3extremophile,Rhazya stricta. These results demonstrate thatR. strictasupports higher rates of photorespiration under elevated temperatures and that these higher rates of photorespiration correlate with increased activity of key photorespiratory enzymes; phosphoglycolate phosphatase and catalase. The increased photorespiratory enzyme activities may increase the overall capacity of photorespiration by reducing enzymatic bottlenecks and allowing minimal inhibitor accumulation under high photorespiratory rates. Additionally, we found the CO2transfer conductances (stomatal and mesophyll) are re‐allocated to increase the water‐use efficiency inR. strictabut not necessarily the photosynthetic response to temperature. These results suggest important adaptive strategies inR. strictathat maintain photosynthetic rates under elevated temperatures with optimal water loss. The strategies found in R. stricta may inform breeding and engineering efforts in other C3species to improve photosynthetic efficiency at high temperatures.

 
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Award ID(s):
2030337
NSF-PAR ID:
10492431
Author(s) / Creator(s):
; ;
Publisher / Repository:
Plant, Cell & Environment
Date Published:
Journal Name:
Plant, Cell & Environment
Volume:
46
Issue:
12
ISSN:
0140-7791
Page Range / eLocation ID:
3704 to 3720
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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