Multiple roles for Vitamin B 6 in plant acclimation to UV-B [Elektronisk resurs]

• Direct and indirect roles of vitamin B 6 in leaf acclimation to supplementary UV-B radiation are shown in vitamin B 6 deficient  Arabidopsis thaliana mutant  rsr4-1 and C24 wild type. Responses to 4 days of 3.9 kJ m -2 d -1 biologically effective UV-B dose were compared in terms of leaf photochemistry, vitamer content, and antioxidant enzyme activities; complemented with a comprehensive study of vitamer ROS scavenging capacities. Under UV-B,  rsr4-1 leaves lost more (34%) photochemical yield than C24 plants (24%). In the absence of UV-B, rsr4-1 leaves contained markedly less pyridoxal-5’-phosphate (PLP) than C24 ones, but levels increased up to the C24 contents in response to UV-B. Activities of class-III ascorbate and glutathione peroxidases increased in C24 leaves upon the UV-B treatment but not in the  rsr4-1 mutant. SOD activities remained the same in C24 but decreased by more than 50% in  rsr4-1 under UV-B. Although PLP was shown to be an excellent antioxidant  in vitro , our results suggest that the UV-B protective role of B 6 vitamers is realized indirectly, via supporting peroxidase defence rather than by direct ROS scavenging. We hypothesize that the two defence pathways are linked through the PLP-dependent biosynthesis of cystein and heme, affecting peroxidases. 

Ämnesord

Natural Sciences  (hsv)

Biological Sciences  (hsv)

Biochemistry and Molecular Biology  (hsv)

Naturvetenskap  (hsv)

Biologiska vetenskaper  (hsv)

Biokemi och molekylärbiologi  (hsv)

Botany  (hsv)

Botanik  (hsv)

Biochemistry  (oru)

Biokemi  (oru)

Genre

government publication  (marcgt)