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A simple and efficient regeneration protocol was developed for watermelon from cotyledonary node explants excised from 7-day-old in vitro grown seedlings. This study describes the effect of amino acids and polyamines (PAs) along with plant growth regulators (PGRs) on multiple shoot induction and rooting. The highest number of multiple shoots (46.43 shoots/explant) was obtained from cotyledonary node and they were also elongated (6.3 cm/shoot) on MS medium supplemented with 1 mg l N -Benzyladenine (BA), 5 mg l leucine, and 10 mg l spermidine. The elongated shoots developed profuse roots (23.03 roots/shoot) in MS medium containing 1 mg l indole-3-butyric acid (IBA), 5 mg l isoleucine, and 10 mg l putrescine. All the rooted plantlets were successfully hardened and acclimatized in the greenhouse with a survival rate of 98%. The present study described an efficient method to obtain a 1.5-fold increase in the number of shoots, compared with the available regeneration protocols for watermelon. The plants developed in this study showed fivefold higher photosynthetic pigments compared to the control plants. The genetic fidelity of the regenerated plants was evaluated by SCoT and RAPD marker analyses, and banding patterns confirmed the true-to-type nature of in vitro regenerated plants. [ABSTRACT FROM AUTHOR]

Regeneration of transformed plants from the Agrobacterium-infected tissue is a time-consuming process and requires hard work. Okra [ Abelmoschus esculentus (L.) Moench] is highly recalcitrant to Agrobacterium-mediated genetic transformation and regeneration. In this study, we established a tissue culture-independent genetic transformation system for okra using seed as an explant. Agrobacterium tumefaciens EHA 105 harbouring the binary vector pCAMBIA 1301- bar was used to infect the okra seeds. Various parameters influencing the okra genetic transformation including, co-cultivation duration, acetosyringone, sonication, and vacuum infiltration have been evaluated. Maximum transformation efficiency of 18.3 % was recorded when the pre-cultured okra seeds were sonicated for 30 min and vacuum infiltrated for 3 min in Agrobacterium suspension containing 100 µM acetosyringone and co-cultivated for 3 days on a medium containing 100 µM acetosyringone. The GUS histochemical analysis confirmed the gus A gene integration and expression, whereas polymerase chain reaction (PCR) and Southern blot hybridization confirmed the bar gene integration and copy number in the transformed okra genome. The transgene was successfully segregated into the progeny plants with a Mendelian inheritance ratio of 3:1. The in planta transformation protocol developed in the present investigation is applicable to transform the okra plants with disease-resistant traits, and the transformed plants can be generated within 60 days. [ABSTRACT FROM AUTHOR]

Regeneration of plants from Agrobacterium tumefaciens infected cell or tissue is a time-consuming process and somaclonal variations are the major bottleneck. Hence, in the present study, a tissue culture-independent genetic transformation system for snake gourd was developed using seed as an explant. Snake gourd seeds were infected with three A. tumefaciens strains harbouring pGA 492 plasmid, and the transformants were selected against BASTA. Several factors influencing the in planta genetic transformation such as Agrobacterium strains, acetosyringone, sonication, and vacuum infiltration, have been evaluated. The maximum transformation efficiency (19.6 %) was recorded when the pre-cultured snake gourd seeds were sonicated for 30-min and vacuum infiltrated for 3-min at 750 mm of Hg in A. tumefaciens EHA 105 suspension containing 100 µM of acetosyringone. The bar gene integration into the snake gourd genome was confirmed by polymerase chain reaction and Southern blot hybridization. The transgene was successfully inherited into the T progeny plants. This transformation method can produce transgenic snake gourd plants in a relatively short time (35-days). [ABSTRACT FROM AUTHOR]

A combined treatment of sonication (2 min) and vacuum infiltration (2 min) stimulated isoflavones production of 75.26 mg g DW which was 15.11-fold higher than control hairy root line at optimal harvest time of 40 days. Addition of MeJ at 100 μM concentration with 72 h exposure time on 30 day-old hairy root culture further enhanced total isoflavones production of 53.16 mg g DW (10.67-fold) and SA at 200 μM concentration with 96 h exposure period enhanced the production of isoflavones (28.79 mg g DW; 5.78-fold). MeJ-treated hairy roots reduced biomass accumulation whereas sonication, vacuum infiltration and SA did not exhibit a negative effect on biomass growth. [ABSTRACT FROM AUTHOR]

A simple and efficient regeneration protocol was established for soybean [ Glycine max (L.) Merrill]. Cotyledonary node explants from 7-day-old in vitro seedlings were used as explants. The effect of different plant growth regulators [ N-benzyladenine (BA), kinetin (KT), thidiazuron (TDZ), gibberellic acid (GA), zeatin riboside (ZTR), indole-3-acetic acid (IAA), and indole-3-butyric acid (IBA)] along with polyamines (Spermidine, spermine, and putrescine) were investigated at different stages of regeneration using direct organogenesis system. Exogenous spermidine (137.69 μM) in shoot induction medium containing optimal BA concentration (2.22 μM) induced maximum number of shoots (39.02 shoots/explant) compared to BA (2.22 μM) alone. Regenerated shoots elongated well in shoot elongation medium containing GA (1.45 μM) and spermine (74.13 μM), and developed profuse roots in root induction medium containing putrescine (62.08 μM). Rooted plantlets were successfully hardened and acclimatized with a survival rate of 92 %. The amenability of the standardized protocol using cultivar PK 416 was tested on four more Indian soybean cultivars JS 90-41, Hara soy, Co1, and Co2 of which PK 416 was found to be the best responding cultivar, with a maximum of 96.94 % shoot induction. [ABSTRACT FROM AUTHOR]

An efficient Agrobacterium-mediated genetic transformation method has been developed for the medicinal plant Podophyllum hexandrum Royle, an important source of the anticancer agent podophyllotoxin. Highly proliferating embryogenic cells were infected with Agrobacterium tumefaciens harbouring pCAMBIA 2301, which contains npt II and gusA as selection marker and reporter genes, respectively. The transformed somatic embryos and plantlets were selected on Murashige and Skoog (MS) basal medium containing kanamycin and germination medium, respectively. GUS histochemical analysis, polymerase chain reaction and Southern blot hybridisation confirmed that gusA was successfully integrated and expressed in the P. hexandrum genome. Compared with cefotaxime, 200 mg l timentin completely arrested Agrobacterium growth and favoured somatic embryo development from embryogenic cells. Among the different Agrobacterium strains, acetosyringone concentrations and co-cultivation durations tested, embryogenic callus infected with A. tumefaciens EHA 105 and co-cultivated for 3 days on MS basal medium containing 100 μM acetosyringone proved to be optimal and produced a transformation efficiency of 29.64 % with respect to germinated GUS-positive plantlets. The Agrobacterium-mediated genetic transformation method developed in the present study facilitates the transference of desirable genes into P. hexandrum to improve the podophyllotoxin content and to enhance other useful traits. [ABSTRACT FROM AUTHOR]

Plants, when exposed to abiotic or biotic stress, produce several pathogenesis-related proteins to counteract the effects of stress. Osmotin is one of the important pathogenesis-related proteins induced during several stress conditions. We have developed improved salt stress tolerant transgenic chilli pepper plants ( Capsicum annum L. var. Aiswarya 2103) by ectopic expression of the Nicotiana tabaccum osmotin gene using Agrobacterium tumefaciens EHA105 as a vector. Four-week-old chilli pepper leaves were used as an explant and A. tumefaciens EHA105 harboring pBINASCOSM plasmid that contains osmotin gene under the control of CaMV 35S promoter and npt II as a selectable marker was used in co-cultivation. Transgene integration and expression were analyzed using molecular, immunochemical, and biochemical assays. PCR and Southern blot analysis confirmed that osmotin gene has been successfully integrated into the genome of chilli pepper plants. The osmotin gene was stably segregated and expressed in T generation transgenic chilli pepper plants, and it was confirmed by Western blot analysis. Biochemical assays of these putative transgenic plants revealed enhanced levels of chlorophyll, proline, glycinebetaine, APX, SOD, DHAR, MDHAR, GR, and relative water content. Yield potential of the putative transgenic chilli pepper plants was evaluated under salinity stress conditions in a green house. The putative transgenic chilli pepper plants overexpressing the osmotin gene were morphologically similar to wild-type plants and produced 3.32 kg chilli pepper fruits per plant at 300 mM NaCl concentration. [ABSTRACT FROM AUTHOR]