Expression of SOD transgene in pepper confer stress tolerance and improve shoot regeneration / Expresión del transgén SOD en el pimiento que confiere tolerancia al estrés y mejora la regeneración de brotes

The objective of this work was to study the stress tolerance and regeneration capability of transgenic pepper plants carrying a sod gene, encoding a tomato chloroplast-localized Cu/Zn SOD protein. The expression of the sod gene was confirmed by enzymatic staining following polyacrylamide gel electrophoresis (PAGE), revealing a ‘novel’ band, which could represent a heterodimeric enzyme. Transgenic T1 and T2 progeny plants were exposed to different oxidative stresses including Methyl viologen (MV) and drought and found to have an increased resistance to oxidative damage. Furthermore, the SOD carrying transgenic pepper plants showed increased levels of regeneration efficiency compared to the wild type pepper plants. Pepper is a recalcitrant species in terms of its in vitro regeneration ability but it could be extremely useful for the development of pharmaceuticals. This approach enables the extent use of pepper for genetic transformation and the production of high valuable products in plants particularly the large fruit varieties.

Calli cultures from Abies equi-trojani (Aschers et Sinten) and changes in antioxidant defense system enzymes.

This study was conducted to explain difficulties of indirect regeneration of forest trees in tissue culture conditions. For this purpose, changes of antioxidant defense system enzymes; superoxide dismutase (SOD), peroxidase (POD) activities were determined during calli formation on young apical shoots of Abies equi-trojani (Aschers et Sinten). Young apical shoots were collected from naturally growing trees and cultured on two different media; Murashige and Skoog (MS) and McCown Woody plant medium (WPM) supplemented with growth regulators benzyl amino purine (BAP), 2,4-dichloro phenoxy acetic acid (2.4-D), kinetin (Kn) in various concentrations for callus induction. WPM media containing 1 mg ml(-1) BAP and 1 mg ml(-1) 2,4-D gave the best calli induction ratio (74%) between tested combinations. POD and SOD enzyme activities were measured both on young shoot explants and 10 day-old calli derived from these explants. POD and SOD enzyme activities were higher being 81.02% and 74.82%, respectively on calli when compared to shoots. The results showed that culture stress tolerated with increased antioxidant enzyme activities could be considered as protective physiological responses in calli cells.