Retarded germination of Nicotiana tabacum seeds following insertion of exogenous DNA mimics the seed persistent behavior

Abstract

Tobacco seeds show a coat-imposed dormancy in which the seed envelope tissues (testa and endosperm) impose a physical constraint on the radicle protrusion. The germination-limiting process is represented by the endosperm rupture which is induced by cell-wall weakening. Transgenic tobacco seeds, obtained by insertion of exogenous genes codifying for seed-based oral vaccines (F18 and VT2eB), showed retarded germination with respect to the wild type and modified the expression of endogenous proteins. Morphological and proteomic analyses of wild type and transgenic seeds revealed new insights into factors influencing seed germination. Our data showed that the interference of exogenous DNA influences the germination rather than the dormancy release, by modifying the maturation process. Dry seeds of F18 and VT2eB transgenic lines accumulated a higher amount of reserve and stress–related proteins with respect to the wild type. Moreover, the storage proteins accumulated in tobacco F18 and VT2eB dry seeds have structural properties that do not enable the early limited proteolysis observed in the wild type. Morphological observations by electron and light microscopy revealed a retarded mobilization of the storage material from protein and lipid bodies in transgenic seeds, thus impairing water imbibition and embryo elongation. In addition, both F18 and VT2eB dry seeds are more rounded than the wild type. Both the morphological and biochemical characteristics of transgenic seeds mimic the seed persistent profile, in which their roundness enables them to be buried in the soil, while the higher content of storage material enables the hypocotyl to elongate more and the cotyledons to emerge.

Seed-specific expression of porcine verotoxigenic Escherichia coli antigens in tobacco plants as a potential model of edible vaccines

“…At the same time, the T0 seed was checked for Kanamycin segregation. The time of germination for both transformations showed similar results compared to a previous study conducted by our research group (from 5 to 7 days) (Onelli et al 2017 ).…”

Evaluation of Dietary Administration of Chestnut and Quebracho Tannins on Growth, Serum Metabolites and Fecal Parameters of Weaned Piglets

“…Due to such restrictions, alternatives to antibiotics and alternatives to zinc oxide are urgently needed to guarantee animal production in line with health principles [ 11 , 12 ]. In this scenario, plant extracts can represent a valuable alternative as a natural source of functional compounds, such as polyphenolic compounds [ 13 , 14 , 15 , 16 , 17 ]. Among polyphenols, tannins derived from plant extracts are the largest class which can be classified into hydrolysable (HTs) or condensed (CTs) subgroups [ 18 ].…”

Could packing and pelleting keep the quality of tobacco seeds during storage?

“…Throughout the storage, there was a tendency to increase the germination speed of seeds in the other packages until approximately 452 days, but the percentage of normal seedlings in the first germination count decreased after that period, according to the regression equation (y= 88.171429 + 0.016799x -0.000017x 2 ; R 2 = 81.67). Probably, the increase of germination speed observed for this period was caused by a dormancy overcoming of the seeds, since the tobacco seeds physiological dormancy is considered to be not deep, induced by the exogenous ABA and the mechanical resistance exerted by the endosperm-test (Leubner-Metzger, 2002;Onelli et al, 2017).…”