Gene Editing of Gibberellin-Oxidase20 improves plant architecture and drought tolerance in maize

As a major plant abiotic stress, drought stress suppresses crop yield performance severely. However, the trade-off between crop drought tolerance and yield performance becomes a great challenge in drought-resistant crop breeding. Several phytohormones have been reported to participate in plant drought response, including gibberellin (GA), which also plays an important role in plant growth and development. Using CRISPR technology, we constructed the null mutant of ZmGA20ox3, a key enzyme in GA biosynthesis. The null mutant plants show lower plant height and ear height with no yield loss under the normal condition than wild-type plants. Transcriptome analysis revealed that genes affected by ZmGA20ox3 were enriched in signal transduction and stress response processes. In addition to the decrease of GA, a significant increase of ABA and JA level were also detected in mutant plants. Compared with wild-type plants, the growth and ASI of mutant plants were less affected, and the yield loss was also reduced under drought conditions. These results suggest a potential role of ZmGA20ox3 in maize drought response. Our result shows that regulating GA biosynthesis is applicable for maize drought-resistant breeding. Overall design: Comparative gene expression profiling analysis of RNA-seq data for ZmGA20ox3 KO mutant plants and WildType (WT) plants.