%0 Journal Article
%T Functional characterization and comparison of lycopene epsilon-cyclase genes in Nicotiana tabacum.
%A Song W
%A Wei F
%A Gao S
%A Dong C
%A Hao J
%A Jin L
%A Li F
%A Wei P
%A Guo J
%A Wang R
%J BMC Plant Biol
%V 22
%N 1
%D May 2022 21
%M 35597910
%F 5.26
%R 10.1186/s12870-022-03634-5
%X BACKGROUND: Lycopene epsilon-cyclase (ε-LCY) is a key enzyme in the carotenoid biosynthetic pathway (CBP) of higher plants. In previous work, we cloned two Ntε-LCY genes from allotetraploid tobacco (Nicotiana tabacum), Ntε-LCY2 and Ntε-LCY1, and demonstrated the overall effect of Ntε-LCY genes on carotenoid biosynthesis and stress resistance. However, their genetic and functional characteristics require further research in polyploid plants.
RESULTS: Here, we used CRISPR/Cas9 to obtain Ntε-LCY2 and Ntε-LCY1 mutants in allotetraploid N.tabacum K326. Ntε-LCY2 and Ntε-LCY1 had similar promoter cis-acting elements, including light-responsive elements. The Ntε-LCY genes were expressed in roots, stems, leaves, flowers, and young fruit, and their highest expression levels were found in leaves. Ntε-LCY2 and Ntε-LCY1 genes responded differently to normal light and high light stress. Both the Ntε-LCY2 and the Ntε-LCY1 mutants had a more rapid leaf growth rate, especially ntε-lcy2-1. The expression levels of CBP genes were increased in the ntε-lcy mutants, and their total carotenoid content was higher. Under both normal light and high light stress, the ntε-lcy mutants had higher photosynthetic capacities and heat dissipation levels than the wild type, and this was especially true of ntε-lcy2-1. The reactive oxygen species content was lower in leaves of the ntε-lcy mutants.
CONCLUSIONS: In summary, the expression patterns and biological functions of the Ntε-LCY genes Ntε-LCY1 and Ntε-LCY2 differed in several respects. The mutation of Ntε-LCY2 was associated with a greater increase in the content of chlorophyll and various carotenoid components, and it enhanced the stress resistance of tobacco plants under high light.