AUTHOR=Hu Ying-Xiong , Tao Yan-Bin , Xu Zeng-Fu 

TITLE=Overexpression of Jatropha Gibberellin 2-oxidase 6 (JcGA2ox6) Induces Dwarfism and Smaller Leaves, Flowers and Fruits in Arabidopsis and Jatropha

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.02103

DOI=10.3389/fpls.2017.02103

ISSN=1664-462X

ABSTRACT=<p>Gibberellins (GAs) are plant hormones that play fundamental roles in plant growth and development. Gibberellin 2-oxidase (GA2ox) plays a direct role in determining the levels of bioactive GAs by catalyzing bioactive GAs or their immediate precursors to inactive forms. In this study, a <italic>GA2ox</italic> gene, designated <italic>JcGA2ox6</italic>, was isolated from <italic>Jatropha curcas</italic>. <italic>JcGA2ox6</italic> is expressed in all tissues of adult <italic>Jatropha</italic>, with the highest expression level in male flowers and the lowest expression level in young leaves. Overexpression of <italic>JcGA2ox6</italic> in <italic>Arabidopsis</italic> resulted in a typical dwarf phenotype, along with late flowering, smaller leaves and flowers, shorter siliques and smaller seeds. Similarly, when <italic>JcGA2ox6</italic> was overexpressed in <italic>Jatropha</italic>, the transgenic plants exhibited a dwarf phenotype with dark-green leaves and smaller inflorescences, flowers, fruits and seeds. However, the flowering time of <italic>Jatropha</italic> was not affected by overexpression of <italic>JcGA2ox6</italic>, unlike that in the transgenic <italic>Arabidopsis</italic>. Moreover, the number of flowers per inflorescence, the weight of 10 seeds and the seed oil content were significantly decreased in transgenic <italic>Jatropha</italic>. The results indicated that overexpression of <italic>JcGA2ox6</italic> had a great impact on the vegetative and reproductive growth of transgenic <italic>Jatropha</italic>. Furthermore, we found that the dwarf phenotype of transgenic <italic>Jatropha</italic> was caused by a decrease in endogenous bioactive GA<sub>4</sub>, which was correlated with the degree of dwarfism.</p>