ROLC strawberry plant adaptability, productivity, and tolerance to soil-borne disease and mycorrhizal interactions

Abstract

The potential to improve strawberry cultivation was assessed regarding the use the rolC genes from Agrobacterium rhizogenes that can confer higher levels of free cytokinins. Strawberry (cv. Calypso) rolC lines were produced by genetic transformation of Agrobacterium tumefaciens. Yield and fruit quality of the control and transgenic lines were measured under open-field conditions. The effects of the transgenic rolC lines depended on gene copy number: rolC lines with one (Line A) or two gene (Line B) copies showed 30% greater yields than controls, due to 20% more fruit per plant and an increased fruit weight. Line A also differed in terms of the highest fruit quality, due to 10.5% increased soluble solids and 12.7% higher acidity. Moreover, cv. Calypso rolC lines A and B had increased tolerance to greenhouse infection by Phytophthora cactorum. Conversely, for all of these characters, Line F (five rolC copies) was not significantly different from the control line. The same lines were also used to examine their symbiosis with root arbuscular mycorrhizal fungi (AMF) using vital and non-vital staining of roots collected at different stages of plant growth. Control and rolC plants showed similar intensities of AMF infection according to plant phenology and/or physiology. Furthermore, possible horizontal gene transfer of the rolC gene was tested for the AMF spores by PCR, with all AMF samples negative using rolC primers. The use of the rolC gene should be considered for the improvements provided in productivity, fruit quality and disease resistance of cultivated strawberry that show no effects on soil microorganisms.

Response of in vitro strawberry to antibiotics

“…Therefore, the optimum concentration of Kan for inducing Plant Growth Regul (2011) 65:183-193 189 Kan-resistant callus is 10 mg L -1 while 50 mg L -1 is suitable for subculture of transformed plantlets using the npt II gene as a selective marker gene in Toyonaka strawberry genetic transformation. Cef and Carb are bactericides widely used to eliminate Agrobacterium during strawberry genetic transformation (Barceló et al 1998;Hokanson and Maas 2001;Folta and Dhingra 2006;Qin and Zhang 2007;Qin et al 2008;Landi et al 2009;Husaini 2010). However, both Cef and Carb have dual (positive or negative) impacts on different explants (Sarma et al 1995;Danilova and Dolgikh 2004;Grewal et al 2006).…”

“…is one of the most important fruits worldwide. In past decades, great progress has been made in strawberry breeding and germplasm improvement through genetic engineering (Hokanson and Maas 2001;Folta and Dhingra 2006;Quesada et al 2007;Qin et al 2008;Landi et al 2009;Husaini 2010). The most effective and widely used method for strawberry genetic transformation is A. tumefaciensmediated transformation using leaf disks as explants (Husaini and Srivastava 2006;Debnath and Teixeira da Silva 2007;Qin et al 2008;Schaart et al 2011).…”

Recent Advances in the Understanding of Agrobacterium rhizogenes-Derived Genes and Their Effects on Stress Resistance and Plant Metabolism

“…It can be hypothesized that activation of defense reactions in transformed plants could provide advantages for A. rhizogenes by inhibiting concurrent pathogenic microorganisms. A recent investigation demonstrated that rolC-transformed strawberry plants possessed increased tolerance to infection by Phytophthora cactorum [39]. An interesting observation was reported about the interaction of Panax ginseng calli with the human pathogen Yersinia pseudotuberculosis [50], in which the cocultivation of Y. pseudotuberculosis and control (vector-transformed) ginseng calli resulted in the rapid death of both bacterial and plant cells, resembling the HRsyndrome known from plant-microbe interactions.…”

Testing Potential Effects of Maize Expressing the Bacillus thuringiensis Cry1Ab Endotoxin (Bt Maize) on Mycorrhizal Fungal Communities via DNA- and RNA-Based Pyrosequencing and Molecular Fingerprinting

“…In nature, soil and plant roots are inhabited by more diverse fungal communities, whose members may respond differently to GM plants. In general, studies where roots of GM plants (Bt or other traits) were subjected to a mixture of AM fungal species, either in microcosms or in the field, no effects of GM plants on AM fungal colonization were reported (12,24,28,38,49).…”