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

AYELÉN GÁZQUEZ; HAMADA ABDELGAWAD; GEERT BAGGERMAN; GEERT VAN RAEMDONCK; HAN ASARD; MAIALE, SANTIAGO JAVIER; ANDRES ALBERTO RODRIGUEZ; GERRIT BEEMSTER

JOURNAL OF EXPERIMENTAL BOTANY

OXFORD UNIV PRESS

Lugar: Oxford; Año: 2019

0022-0957

We analysed the cellular and molecular changes in the leaf growth zone of tolerant and sensitive rice varieties in response to suboptimal temperatures. Cold reduced the final leaf length by 35% and 51% in tolerant and sensitive varieties, respectively. Tolerant lines exhibited a smaller reduction of the leaf elongation rate and greater compensationby an increased duration of leaf growth. Kinematic analysis showed that cold reduced cell production in the meristemand the expansion rate in the elongation zone, but the latter was compensated for by a doubling of the duration ofcell 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 68between treatments, in the tolerant and sensitive lines, respectively. The categories protein biosynthesis and redoxhomeostasis were significantly overrepresented in the up-regulated proteins. We therefore 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 up-regulate enzymatic antioxidants in the meristem and non-enzymatic antioxidantsin the elongation zone.