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Crop Biotech Update

Overexpression of PtCYP85A3 Promotes Growth and Biomass Production in Poplar

June 28, 2017

Brassinosteroids (BR) play crucial roles in plant growth, reproduction and response to abiotic and biotic stress. In Arabidopsis, AtCYP85A2 catalyses the conversion of castasterone to brassinolide, a final step in the BR biosynthetic pathway. Yan-Li Jin of the Chinese Academy of Sciences led a team of researchers to characterize PtCYP85A3, one of the three AtCYP85A2 homologs from poplar (Populus trichocarpa).

The team found that PtCYP85A3 is highly similar to AtCYP85A2 and can rescue the retarded-growth phenotype of the Arabidopsis cyp85a2-2 and tomato mutants. Expression of PtCYP85A3, driven by the cauliflower mosaic virus 35S promoter, increased the BR levels and significantly promoted the growth and biomass production in both transgenic tomato and poplar.

The plant height, shoot fresh weight and fruit yield all increased in transgenic tomato plants. Similarly, plant height and stem diameter both increased in transgenic poplar plants. Further studies revealed that overexpression of PtCYP85A3 enhanced xylem formation without affecting the composition of cellulose and lignin in transgenic poplar.

These results suggest that PtCYP85A3 could be used for engineering fast-growing trees with improved wood production.

For more information, read the article in Plant Biotechnology Journal.