Redox homeostasis in the rice leaf growth zone plays a key role in cold tolerance

GÁZQUEZ, AYELÉN; ABDELGAWAD, HAMADA; BAGGERMAN, GEERT; RAEMDONCK, GEERT VAN; ASARD, HAN; MAIALE, SANTIAGO JAVIER; RODRÍGUEZ, ANDRÉS ALBERTO; BEEMSTER, GERRIT T S

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Año: 2020 vol. 71 p. 1053 - 1066

0022-0957

We analyzed the cellular and molecular changes in the leaf growth zone of tolerant and sensitive rice varieties in response to suboptimal temperatures. Cold reduced final leaf length by 35 and 51% in tolerant and sensitive varieties, respectively. Tolerant lines exhibited a smaller reduction of leaf elongation rate and a larger compensation by increased duration of leaf growth. Kinematic analysis showed that cold reduced cell production in the meristem and expansion rate in the elongation zone, but the latter was compensated for by a doubling of the duration of cell expansion. We performed iTraq proteome analysis on proliferating and expanding parts of the leaf growth zone. We identified 559 and 542 proteins of which 163 and 210 were differentially expressed between zones and 96 and 68 between treatments in the tolerant and sensitive line, respectively. The categories protein biosynthesis and redox homeostasis were significantly overrepresented in the upregulated proteins. We therefor measured redox metabolites and enzyme activities in the leaf growth zone, demonstrating that tolerance of rice lines to suboptimal temperatures correlates with the ability to upregulate of enzymatic antioxidants in the meristem and non-enzymatic antioxidants in the elongation zone.