Mg-Protoporphyrin IX Signals Enhance Plant's Tolerance to Cold Stress.
The relationship between Mg-protoporphyrin IX (Mg-Proto IX) signals and plant's tolerance to cold stress is investigated.Arabidopsisseedlings grown for 3 weeks were pretreated with 2 mM glutamate (Glu) and 2 mM MgCl2for 48 h at room temperature to induce Mg-Proto IX accumulation. Then cold stress was performed at 4°C for additional 72 h. Glu + MgCl2pre-treatments alleviated the subsequent cold stress significantly by rising the leaf temperature through inducing Mg-Proto IX signals. The protective role of Glu + MgCl2treatment was greatly compromised in the mutants of Mg-Proto IX synthesis, Mg-Proto IX signaling, and cyanide-resistant respiration. And the enhancement of cold-responsive gene expression was greatly compromised in the mutants of Mg-Proto IX synthesis, Mg-Proto IX signaling and ABA signaling, but not in the mutant of cyanide-resistant respiration. Cold stress promoted cyanide-resistant respiration and leaf total respiration exponentially, which could be further induced by the Glu + MgCl2treatment. Mg-Proto IX signals also activate antioxidant enzymes and increase non-enzymatic antioxidants [glutathione but not ascorbic acid (AsA)] to maintain redox equilibrium during the cold stress.
College of Resources, Sichuan Agricultural University Chengdu, China.
Zhong-Wei
ZW
Zhang
Key Lab of Aromatic Plant Resources Exploitation and Utilization in Sichuan Higher Education, College of Life Science and Food Engineering, Yibin University Yibin, China.
Zi-Li
ZL
Wu
College of Resources, Sichuan Agricultural University Chengdu, China.
Ling-Yang
LY
Feng
College of Life Sciences, Sichuan Agricultural University Ya'an, China.
Li-Hua
LH
Dong
College of Resources, Sichuan Agricultural University Chengdu, China.
An-Jun
AJ
Song
College of Life Sciences, Sichuan Agricultural University Ya'an, China.
Ming
M
Yuan
College of Life Sciences, Sichuan Agricultural University Ya'an, China.
Yang-Er
YE
Chen
College of Resources, Sichuan Agricultural University Chengdu, China.
Jian
J
Zeng
College of Resources, Sichuan Agricultural University Chengdu, China.
Guang-Deng
GD
Chen
College of Resources, Sichuan Agricultural University Chengdu, China.
Shu
S
Yuan
Mg-protoporphyrin IX signals; antioxidant enzyme; cold stress; cyanide-resistant respiration; glutathione