Water stress is one harmful environmental stress during plant growth and development, leading to a great loss in crop yield. In response to environmental stresses including dehydration, salt, and low temperature, plants have developed various adaptive alterations in growth and development, and most of which are dependent on ABA. Under dehydration stress condition (soil water de？cit), plant endogenous ABA increased to relatively higher level to regulate downstream gene expressions and physiological changes.
Dr. SHI Haitao under the supervision of Professor CHAN Zhulong from Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden assigned new role for AtAMP1 in ABA signaling and dehydration stress of Arabidopsis.
AtAMP1 was transcriptionally down-regulated by ABA. Loss -of-function mutant of AtAMP1 (amp1-1, encoding a premature stop codon in AtAMP1) resulted in hypersensitive phenotypes toward ABA-mediated seed germination and primary root elongation. The amp1-1 mutant also exhibited enhanced dehydration resistance, as evidenced by the changes of electrolyte leakage (EL), water loss rate and survival rate. Notably, the amp1-1 lines exhibited higher expression levels of ABA-responsive genes (RAB18, RD29A and RD29B), higher concentration of proline and lower reactive oxygen species (ROS) levels (H2 O2 and O2？-) after ABA and dehydration treatments than those of wild type. These observations indicated a negative role for AtAMP1 in ABA-mediated dehydration stress response, will contribute to the molecular mechanism research of ABA signaling.
Relevant results entitled “Arabidopsis ALTERED MERISTEM PROGRAM 1 negatively modulates plant responses to abscisic acid and dehydration stress” were published in Plant Physiology and Biochemistry online.
Dehydration tolerance test of wild type and amp1-1 mutant plants (A); A proposed model for AtAMP1-mediated dehydration-stress signal transduction (B). (Image by CHAN’s group)
