Overexpression of Populus trichocarpa CYP85A3 promotes growth and biomass production in transgenic trees

Abstract

SummaryBrassinosteroids (BRs) are essential hormones that play crucial roles in plant growth, reproduction and response to abiotic and biotic stress. In Arabidopsis, AtCYP85A2 works as a bifunctional cytochrome P450 monooxygenase to catalyse the conversion of castasterone to brassinolide, a final rate‐limiting step in the BR‐biosynthetic pathway. Here, we report the functional characterizations of PtCYP85A3, one of the three AtCYP85A2 homologous genes from Populus trichocarpa. PtCYP85A3 shares the highest similarity with AtCYP85A2 and can rescue the retarded‐growth phenotype of the Arabidopsis cyp85a2‐2 and tomato d x mutants. Constitutive expression of PtCYP85A3, driven by the cauliflower mosaic virus 35S promoter, increased the endogenous BR levels and significantly promoted the growth and biomass production in both transgenic tomato and poplar. Compared to the wild type, plant height, shoot fresh weight and fruit yield increased 50%, 56% and 43%, respectively, in transgenic tomato plants. Similarly, plant height and stem diameter increased 15% and 25%, respectively, in transgenic poplar plants. Further study revealed that overexpression of PtCYP85A3 enhanced xylem formation without affecting the composition of cellulose and lignin, as well as the cell wall thickness in transgenic poplar. Our finding suggests that PtCYP85A3 could be used as a potential candidate gene for engineering fast‐growing trees with improved wood production.

Brassinosteroid overproduction improves lignocellulose quantity and quality to maximize bioethanol yield under green-like biomass process in transgenic poplar

“…2). Hence, our results indicated that PtoDET2 could significantly increase BRs level for much enhanced plant growth and biomass yield, consistent with the previous findings that BRs-related genes could promote plant growth [31][32][33][34][35][36][37][38][39][40].…”

“…BRs are the plant-specific steroid hormones that dynamically regulate plant growth and development [30][31][32][33][34][35][36]. In this study, we observed a fast growth and development with more internodes and larger leaves in the PtoDET2-OE transgenic lines ( Fig.…”

“…BIN2 controls the stabilization and activation of BRASSINAZOLE-RESISTANT1 (BRZ1) and BR-INSENSITIVE-EMS-SUPPRESSOR 1 (BES1/BZR2), and therefore to regulate the transcription of BR-responsive target genes [31,32]. Overexpression of BR biosynthesis or signaling genes led to more xylem formation and increased cell wall deposition [31][32][33][34][35][36]. Although increasing evidence has established the connection between BRs and wood formation, the role of BRs during cell wall polysaccharide biosynthesis and modification is not well revealed, and the effects of BRs in bioethanol production are largely unknown.…”

PeCHYR1, a ubiquitin E3 ligase from Populus euphratica, enhances drought tolerance via ABA‐induced stomatal closure by ROS production in Populus

“…Every transgenic line was verified by PCR, RT‐qPCR and histochemical staining with β‐glucuronidase (GUS) (Figure S2). In the literature, these three methods are usually used to verify transgenic plants (Jin et al ., ).…”

Brassinosteroids: Multidimensional Regulators of Plant Growth, Development, and Stress Responses

“…Secondary cell walls in the form of wood and fibers are the most abundant, renewable plant products, and there is a high demand for improving wood and fiber production. Overexpression of Populus trichocarpa CYP85A3, encoding a P450 monooxygenase that catalyzes the conversion of castasterone to BL, enhanced xylem formation and wood production in poplar while the composition of cellulose and lignin and cell wall thickness were not affected, making Populus trichocarpa CYP85A3 a good target for engineering fast-growing woods (Jin et al, 2017). BR signaling also regulates cotton (Gossypium hirsutum) fiber development by modifying the expression of DET2 and PAGPDA1.…”