Rice mutants deficient in ω-3 fatty acid desaturase (FAD8) fail to acclimate to cold temperatures.
To investigate the role of ω-3 fatty acid (FA) desaturase (FAD8) during cold acclimation in higher plants, we characterized three independent T-DNA insertional knock-out mutants of OsFAD8 from rice (Oryza sativa L.). At room temperature (28 °C), osfad8 plants exhibited significant alterations in fatty acid (FA) unsaturation for all four investigated plastidic lipid classes. During a 5-d acclimation period at 4 °C, further changes in FA unsaturation in both wild-type (WT) and mutant plants varied according to the type of lipid. We also monitored the fluidity of the thylakoid membrane using a threshold temperature to represent the change in fluorescence. The values were altered significantly by both FAD8 mutation and cold acclimation, suggesting that factors other than FAD8 are involved in C18 FA unsaturation and fluctuations in membrane fluidity. Similarly, significant changes were noted for both the mutant and WT samples in terms of their FA compositions as well as activities related to photosystem (PS) I, PSII, and photoprotection. This included the development of non-photochemical quenching and increased zeaxanthin accumulation. Despite the relatively small changes in FA composition during cold acclimation, cold-inducible FAD8 knock-out mutants displayed strong differences in photoprotective activities and a further drop in membrane fluidity. The mutants were more sensitive than WT to short-term low-temperature stress that resulted in increased production of reactive oxygen species after 5 d of chilling. Taken together, our findings suggest that FA unsaturation by OsFAD8 is crucial for the acclimation of higher plants to low-temperature stress.
Department of Integrated Biological Science, Department of Molecular Biology, Pusan National University, Busan 609-735, Republic of Korea; Department of Biotechnology, Breeding, Mongolian University of Life Sciences, Zaisan 17024, Ulaanbaatar, Mongolia.
Altanzaya
A
Tovuu
Department of Integrated Biological Science, Department of Molecular Biology, Pusan National University, Busan 609-735, Republic of Korea; Department of Biology, North-Eastern Federal University, 58 Belinsky Str., Yakutsk 677-027, Republic of Sakha (Yakutia), Russian Federation; Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Matbuat Avenue 2a, Baku, AZ 1073, Azerbaijan.
Ismayil S
IS
Zulfugarov
Department of Integrated Biological Science, Department of Molecular Biology, Pusan National University, Busan 609-735, Republic of Korea.
Guangxi
G
Wu
Department of Biological Sciences, Inje University, Gimhae 621-749, Republic of Korea; Department of Pharmacology, School of Medicine, Inha University, Incheon 22212, Republic of Korea.
In Soon
IS
Kang
Department of Statistics, Pusan National University, Busan 609-735, Republic of Korea.
Choongrak
C
Kim
Department of Biological Sciences, Inje University, Gimhae 621-749, Republic of Korea.
Byoung Yong
BY
Moon
Crop Biotech Institute, Kyung Hee University, Yongin 446-701, Republic of Korea.
Gynheung
G
An
Department of Integrated Biological Science, Department of Molecular Biology, Pusan National University, Busan 609-735, Republic of Korea. Electronic address: chlee@pusan.ac.kr.
Choon-Hwan
CH
Lee
D000064:Acclimatization / Q000235:genetics / Q000502:physiology; D003081:Cold Climate; D044943:Fatty Acid Desaturases / Q000172:deficiency* / Q000235:genetics*; D005231:Fatty Acids, Unsaturated / Q000737:chemistry / Q000378:metabolism; D055786:Gene Knockout Techniques; D017343:Genes, Plant; D008560:Membrane Fluidity; D009154:Mutation; D012275:Oryza / Q000201:enzymology / Q000235:genetics* / Q000502:physiology*; D045331:Photosystem I Protein Complex / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism
D005231:Fatty Acids, Unsaturated; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D044943:Fatty Acid Desaturases; C078565:omega-3 fatty acid desaturase
Cold acclimation; Fatty acid desaturase; Membrane fluidity; Reactive oxygen species; Rice