Effects of molybdenum on expression of cold-responsive genes in abscisic acid (ABA)-dependent and ABA-independent pathways in winter wheat under low-temperature stress.
OBJECTIVE
Molybdenum (Mo) is an essential trace element for higher plants. It has been shown that application of Mo enhances the cold resistance of winter wheat. In order to improve our understanding of the molecular mechanisms of cold resistance arising from application of Mo in winter wheat, investigations were made regarding the transcription of cold-responsive (COR) genes in abscisic acid (ABA)-dependent and ABA-independent pathways in winter wheat regulated by Mo application under low-temperature stress.


METHODS
Two cultivars of winter wheat (Triticum aestivum), Mo-efficient cultivar '97003' and Mo-inefficient cultivar '97014', were grown in control (-Mo) and Mo fertilizer (+Mo) treatments for 40 d at 15/12 degrees C (day/night), and the temperature was then reduced to 5/2 degrees C (day/night) to create low-temperature stress. Aldehyde oxidase (AO) activities, ABA contents, the transcripts of basic leucine zipper (bZIP)-type transcription factor (TF) genes, ABA-dependent COR genes, CBF/DREB transcription factor genes and ABA-independent COR genes were investigated at 0, 3, 6 and 48 h post cold stress.


RESULTS
Mo application significantly increased AO activity, ABA levels, and expression of bZIP-type TF genes (Wlip19 and Wabi5) and ABA-dependent COR genes (Wrab15, Wrab17, Wrab18 and Wrab19). Mo application increased expression levels of CBF/DREB transcription factor genes (TaCBF and Wcbf2-1) and ABA-independent COR genes (Wcs120, Wcs19, Wcor14 and Wcor15) after 3 and 6 h exposure to low temperature.


CONCLUSIONS
Mo might regulate the expression of ABA-dependent COR genes through the pathway: Mo --> AO --> ABA --> bZIP --> ABA-dependent COR genes in winter wheat. The response of the ABA-dependent pathway to Mo was prior to that of the ABA-independent pathway. Similarities and differences between the Mo-efficient and Mo-inefficient wheat cultivars in response to Mo under cold stress are discussed.
Sun
Xuecheng
X
Key Laboratory of Subtropical Agriculture and Environment, Ministry of Agriculture, Wuhan, China.
Hu
Chengxiao
C
Tan
Qilin
Q
Liu
Jinshan
J
Liu
Hongen
H
D000040:Abscisic Acid / Q000378:metabolism*; D042931:Aldehyde Oxidase / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics; D003080:Cold Temperature; D005615:Freezing; D018506:Gene Expression Regulation, Plant / Q000187:drug effects* / Q000235:genetics; D008982:Molybdenum / Q000494:pharmacology*; D010940:Plant Proteins / Q000235:genetics*; D016133:Polymerase Chain Reaction; D013312:Stress, Physiological / Q000502:physiology*; D014131:Trace Elements / Q000494:pharmacology*; D014908:Triticum / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*
D050976:Basic-Leucine Zipper Transcription Factors; D010940:Plant Proteins; D014131:Trace Elements; D000040:Abscisic Acid; D008982:Molybdenum; D042931:Aldehyde Oxidase