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The effects of nitric oxide (NO) donor sodium nitroprusside (SNP) and various growth regulators on callus induction and shoot organogenesis in the commercially and pharmaceutically important medicinal plant Valeriana jatamansi is presented. Four different growth regulators at different concentrations were tested for their callusing efficiency followed by supplementation of SNP to the best responding growth regulator. Maximum callusing frequency (91.18%) was observed with the supplementation of 1.5 mg/L 1-Naphthaleneacetic acid + 15 μM SNP. 10% Coconut water (CW) was found to be the best growth regulator for the induction of shoots. The multiple shoot formation was also found to be enhanced with the supplementation of SNP. Maximum response for in vitro shoot multiplication was observed when the medium was supplemented with 10% CW + 15 μM SNP (89.32%) as compared to shoots induced in medium supplemented with 1.5 mg/L Benzyl aminopurine + 15 μM SNP (79.46%) respectively. No separate root induction medium was required as CW and CW + SNP supplementation was found to be sufficient enough to produce profuse rooting of the in vitro regenerated plants. Results revealed that SNP enhanced the callus and shoot induction frequencies. Supplementation of SNP also significantly reduced callus browing, allowed the tissues to recover and regenerate. This proposed in vitro culture system will be an effective mass propagation strategy for both commercial utilization and conservation of this highly valued plant species. Key MessageFirst report using SNP and growth hormone supplementation for enhanced propagation in Valeriana jatamansi presented. Supplementation of SNP enhanced the callus, multiple shoot induction and reduced callus browning in the in vitro cultures of V. jatamansi.

Agrobacterium-mediated transient gene expression have become a method of choice over stable plant genetic transformation. Tocopherols are a family of vitamin E compounds, which are categorized along with tocotrienols occurring naturally in vegetable oils, nuts and leafy green vegetables. This is the first report involving AtTC and AtHPT transient expression in Nicotiana benthamiana and this system can be used efficiently for large scale production of vitamin E. Agroinfiltration studies were carried out in N.benthamiana for the expression of Arabidopsis thaliana (At) genes encoding homogentisate phytyltransferase (HPT) and tocopherol cyclase (TC) individually and in combination (HPT + TC). The transgene presence was analyzed by reverse transcription PCR, which showed the presence of both the vitamin E biosynthetic pathway genes. The gene expression analysis was carried out by (reverse transcription quantitative real-time polymerase chain reaction) RT-qPCR and α-tocopherol content was quantified using high performance liquid chromatography (HPLC). The relative gene expression analysis by RT-qPCR confirmed an increased expression pattern where TC + HPT combination recorded the highest of 231 fold, followed by TC gene with 186 fold, whereas the HPT gene recorded 178 fold. The α-tocopherol content in leaves expressing HPT, TC, and HPT + TC was increased by 4.2, 5.9 and 11.3 fold, respectively, as compared to the control. These results indicate that the transient expression of HPT and TC genes has enhanced the vitamin E levels and stable expression of both A. thaliana genes could be an efficient strategy to enhance vitamin E biosynthesis in agricultural crop breeding.

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