ObjectiveGA20ox is one of the genes coding key rate-limiting enzymes, GA20-oxidases (GA20ox), for biosynthesis of bioactive gibberellins (GA) which involve in many biology process of plant growth and development. At present, it is still not clear that the biological function of GAs in plant leaf development. The aim of this research is to reveal the roles of PsnGA20ox1 in the leaves of overexpression tobacco.

MethodIn this study, we systematically analyzed the leaf size, ultrastructure, biomass, chlorophyll and bioactivity GAs contents, and gene expression level involved in cell division and stomatal formation of PsnGA20ox1 overexpression tobacco and wild-type plants.

ResultOur results revealed that the PsnGA20ox1 overexpression tobacco displayed the enlarged leaf size, enhanced chlorophyll and GA₄ contents, and decreased epidermal cell size. In addition, the thickness of palisade and spongy parenchyma, the sizes of epidermal cell, the numbers of stomatal and epidermal cell, and photosynthesis and leaf biomass productivity of PsnGA20ox1 overexpression tobacco were notably increased compared with wild-type tobacco, respectively. Furthermore, the expression levels of genes involved in cell division and stomatal formation in PsnGA20ox1 overexpression tobacco altered notably, and the variation tendency was in accordance with the alternations of leaf trait.

ConclusionThe results demonstrated that the overexpression of PsnGA20ox1 had effect on the structure and development of leaf in the transgenic tobacco, which is beneficial to the accumulation of biomass of leaf.