Overexpression of Rice BSR2 Confers Disease Resistance and Induces Enlarged Flowers in Torenia fournieri Lind

Abstract

Plant pathogens evade basal defense systems and attack different organs and tissues of plants. Genetic engineering of plants with genes that confer resistance against pathogens is very effective in pathogen control. Conventional breeding for disease resistance in ornamental crops is difficult and lagging relative to that in non-ornamental crops due to an inadequate number of disease-resistant genes. Therefore, genetic engineering of these plants with defense-conferring genes is a practical approach. We used rice BSR2 encoding CYP78A15 for developing transgenic Torenia fournieri Lind. lines. The overexpression of BSR2 conferred resistance against two devastating fungal pathogens, Rhizoctonia solani and Botrytis cinerea. In addition, BSR2 overexpression resulted in enlarged flowers with enlarged floral organs. Histological observation of the petal cells suggested that the enlargement in the floral organs could be due to the elongation and expansion of the cells. Therefore, the overexpression of BSR2 confers broad-spectrum disease resistance and induces the production of enlarged flowers simultaneously. Therefore, this could be an effective strategy for developing ornamental crops that are disease-resistant and economically more valuable.

Enhanced Resistance to Fungal and Bacterial Diseases Due to Overexpression of BSR1, a Rice RLCK, in Sugarcane, Tomato, and Torenia

“…Since BSR1 overexpression confers resistance against R. solani in Arabidopsis and tomatoes, we investigated this effect in ornamental crops. We used torenia as a representative ornamental crop because it has a simple flower structure and is easy to culture and transform [ 13 ]. The BSR1 expression vector, used for tomato transformation, was used for transforming the Torenia fournieri Lind.…”

“…One vigorously growing F1 hybrid plant was propagated vegetatively via herbaceous cutting by Dr. Ryutaro Aida and used as the experimental line in this study. The WT and transgenic torenia plants were cultured and maintained as previously described [ 13 ].…”

“…To generate transgenic tomato and torenia plants that overexpressed BSR1, the full-length cDNA fragment of BSR1 was inserted downstream of the CaMV 35S promoter at the Sfi I sites of the recombinant binary vector pBIG2113SF [ 9 ] and the resulting plasmid pBIG2113SF-BSR1 was introduced into Rhizobium radiobacter strain EHA105. This construct was employed to generate lines of transgenic tomato and torenia plants using the Rhizobium -mediated method [ 13 , 33 , 34 ]. In torenia, T0 and WT plants were propagated through cuttings and used for the subsequent experiments.…”

“…The bacterial pathogen assay for Pst DC3000 in tomatoes was performed as previously described [ 12 ]. Additionally, the soil inoculation assay of R. solani in Arabidopsis , tomato, and torenia was performed as previously described [ 12 , 13 ].…”

PeCIN8 expression correlates with flower size and resistance to yellow leaf disease in Phalaenopsis orchids

“…tomato DC3000 (PstDC3000) and the fungal pathogens Colletotrichum higginsianum and Rhizoctonia solani in Arabidopsis thaliana . In addition, BSR2 -overexpressing plants showed enlarged flowers with enlarged floral organs because of the expansion of cells [ 35 ]. Thus, different mechanisms may lead to disease resistance and be accompanied with either reduced or enlarged flower size.…”