In the present study, 30 Ri-transformed root lines of peanut (Arachis hypogaea) cv. JL-24, a popular Indian cultivar, obtained following infection with Agrobacterium rhizogenes strains LBA9402, A4 and R1000 were selected on the basis of growth index and maintained in vitro for 3 years. The root lines showed high degree of branching and rapid, plagiotropic growth on phytohormone free solid N/5 medium but were devoid of root hairs. Trans-resveratrol was isolated by preparative HPLC from Ri-transformed roots and identified by ESI–MS/MS. Strain independent variability was observed among 30 Ri-transformed root lines on the basis of lateral root density per cm (7.60 ± 0.30 to 4.5 ± 0.5), relative thickness (0.54 ± 0.07 to 1.54 ± 0.1 mm), growth index (9.16 ± 1.1 to 17.79 ± 1.35 FW basis and 10.77 ± 0.95 to 19.46 ± 1.78 DW basis) and trans-resveratrol content 0.27 ± 0.03 (root line R1000-1) to 0.969 ± 0.141 mg g DW−1 (root line RIX-19) in solid N/5 medium, which was 4.1–14 fold greater than in excised non-transformed root cultures (0.06 ± 0.01 mg g DW−1). Optimum growth and productivity in liquid culture was achieved in N/5 medium supplemented with 0.01 % activated charcoal. Root line RIX-19 showed maximum trans-resveratrol accumulation (1.21 ± 0.09 mg g DW−1) and productivity (0.37 ± 0.08 mg per flask), which was 19 fold higher than non-transformed root cultures. This optimized protocol can be utilized for large scale cultivation of transformed root cultures in industrial bioreactors for mass synthesis of trans-resveratrol. © 2015, Springer Science+Business Media Dordrecht.

M HALDER

S JHA

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Plant Cell, Tissue and Organ Culture

Induction of hairy roots by Agrobacterium rhizogenes and regeneration of Ri-transformed plants from such transgenic roots are reported in a large number of taxonomically diverse plant species. Ri-transformed cultures (roots/calli/plants) have altered characteristics of their own compared to non-transformed ones. Four rol genes (rolA, rolB, rolC, rolD) of T-DNA of Ri-plasmid are known to be responsible for these phenomena. However, few attempts have been made to elucidate the role of individual rol genes on morphogenic ability. In addition, the effect of wild-type A. rhizogenes on the production of secondary metabolites is well studied in wide number of plant species. The popularity of this research has never declined through time which explains its immense value and provides a hope for a promising future. Based on such studies, several reviews have been written from time to time, explaining the ‘rol effect’ on secondary metabolite accumulation in medicinal plants and to discuss the advances in this field of research. However, investigations dealing with the effect of individual rol genes are comparatively less and need further attention. Therefore, in this chapter, we have discussed in detail the effects of each of the four rol genes individually or in combination on in vitro morphogenesis and secondary metabolite accumulation in medicinal plants. © Springer Nature Singapore Pte Ltd. 2018.

Biotechnological Approaches for Medicinal and Aromatic Plants: Conservation, Genetic Improvement and Utilization

The effects of rol genes of Agrobacterium rhizogenes on morphogenesis and secondary metabolite accumulation in medicinal plants

Agrobacterium rhizogenes (Ri) transformed root lines of Tylophora indica were established and characterized on the basis of morphology, insertion and expression of T-DNA genes, DNA profiling and tylophorine content in order to study the stability of Ri-transformed root lines in long term culture. Morphologically Ri-transformed root lines were of four phenotypes—moderately branched thin roots, moderately branched thick roots, highly branched thin roots and highly branched thick roots. On the basis of the presence and expression of different T-DNA genes, the Ri-transformed root lines could be divided into two groups—Group I (13 %): TL+/TR+ and Group II (87 %): TL+/TR−. The presence and expression of TR-DNA in addition to TL-DNA did not have any effect on the root morphology and tylophorine content. Tylophorine content varied from 1.01 ± 0.05 to 1.25 ± 0.02 mg gDW−1 in 15 Ri-transformed root lines studied. The transformed root lines stably retained their characteristic phenotype, growth rate, integration and expression of T-DNA genes and tylophorine accumulation potential in long term culture i.e., for 4 years. None of the root lines showed any difference in DNA fingerprinting profiles for each of the 11 OPA primers, showing genetic stability and clonal fidelity of the root lines and root clones in long term culture. Transformed root lines A420 and A426 showing high tylophorine content (1.24 ± 0.03 and 1.22 ± 0.05 mg gDW−1 respectively) even after 4 years of maintenance in vitro on phytohormone unsupplemented medium can be used for scale up studies. This work endorses the utility of T. indica transformed roots for the production of secondary metabolites in bioreactors. © 2014, Springer Science+Business Media Dordrecht.

Plant Growth Regulation

Morphological and molecular variation in Ri-transformed root lines are stable in long term cultures of Tylophora indica

An efficient transformation system for Rauvolfia serpentina, commonly known as “sarpagandha”, an important medicinal shrub of tropical countries of Asia, was established following infection with Agrobacterium rhizogenes strain LBA 9402 using stem and leaf explants of axenic in vitro grown plants. The roots grew rapidly on hormone-free modified Murashige and Skoog’s medium and root growth varied substantially among the ten transformed root lines. PCR and RT-PCR analysis revealed presence and expression of rolA and rolB genes at the transcription level in Ri-transformed root lines. The transformed root lines showed significant differences (p ≤ 0.05) on the basis of their reserpine content. High accumulation of reserpine was obtained in the root lines RsIX6 (3.11 ± 0.26 mg g−1 DW), RsIXA (2.54 ± 0.66 mg g−1 DW) and RsIX18 (2.26 ± 0.26 mg g−1 DW). This is the first report of detection of reserpine in quantifiable amounts from LBA 9402-transformed root lines of R. serpentina. © 2014, Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.

Acta Physiologiae Plantarum

Genetic transformation of sarpagandha (Rauvolfia serpentina) with Agrobacterium rhizogenes for identification of high alkaloid yielding lines

A large number of plant species from several families have been successfully transformed by Agrobacterium rhizogenes and established in culture. In contrast to normal roots, the Ri-transformed root cultures are fast growing, and do not require exogenous supply of plant growth regulators in the medium to support growth. In addition, they are robust, plagiotropic, and produce the full range of secondary products characteristics of roots derived from the parent plant species. Ri transformed roots of some species synthesize novel compounds and screening and selection procedure can also be employed to improve production levels. The most interesting applications of hairy root cultures in a continuous culture program, are with secondary product pathways exclusively active in roots, and from which the product would be secreted into the medium. Large-scale secondary metabolite production from hairy roots can be achieved by using different types of bioreactors. In this review, we provide an overview of synthesis and accumulation of medicinally important secondary metabolites in Ri transformed root cultures and in Ri-transformed plants. © 2013 Springer-Verlag Berlin Heidelberg. All rights are reserved.

Biotechnology for Medicinal Plants: Micropropagation and Improvement

Agrobacterium rhizogenes-mediated transformation in medicinal plants: Prospects and challenges

We have developed an efficient transformation system for Bacopa monnieri, an important Indian medicinal plant, using Agrobacterium rhizogenes strains LBA 9402 and A4. Transformed roots induced by strain LBA 9402 spontaneously dedifferentiated to callus while excised roots induced by strain A4 spontaneously showed induction of shoot buds within 10 days. PCR and RT-PCR analysis revealed the presence and expression of the rolAB and rolC genes at the transcription level in pRi A4 transformed cultures indicating that the TL-DNA was integrated retained and expressed in the A4-Ri transformed shoots. Transformed calli showed the presence of rolAB or rol A, TR and ags genes. Transformed plants showed morphological features typically seen in transgenic plants produced by A. rhizogenes. Growth and biomass accumulation was significantly higher in the transformed shoots (twofold) and roots (fourfold) than in the non-transformed (WT) plants. In pRi A4-transformed plants, the content of bacopasaponin D, bacopasaponin F, bacopaside II and bacopaside V was enhanced significantly as compared to WT plants of similar age while bacoside A3 and bacopasaponin C content was comparable with that of WT plants. Significant increase in content of five bacopa saponins could be detected in pRi 9402-transformed callus cultures. There is an overall stimulatory effect on accumulation of bacopa saponins in transformed plants and cells of B. monnieri establishing the role of endogenous elicitation by Ri T-DNA of A. rhizogenes. © 2011 Springer-Verlag.

Plant Cell Reports

Genetic transformation of Bacopa monnieri by wild type strains of Agrobacterium rhizogenes stimulates production of bacopa saponins in transformed calli and plants

Arachis hypogea is a non-"infection thread" (IT) legume where rhizobial entry or dissemination in the nodules never involves IT. Rhizobia invade through epidermal "cracks" and directly access the cortical cells to develop the characteristic aeschynomenoid nodules. For investigating these nonclassical nodulation features in Arachis spp., we developed an efficient procedure for Agrobacterium rhizogenes R1000-mediated transformation of this plant. In this study, we optimized the induction of hairy roots and nodulation of composite Arachis hypogea plants in the presence of Bradyrhizobium sp. (Arachis) strain NC92. 35S promoterdriven green fluorescent protein and β-glucuronidase expression indicated transformation frequency to be above 80%. The transformed roots had the characteristic rosettetype root hairs and had normal level of expression of symbiosis-related genes SymRK and CCaMK. The transgenic nodules resembled the wild-type nodules with an exception of 2 to 3%, where they structurally deviated from the wildtype nodules to form nodular roots. A 16S rRNA profile of an infected-zone metagenome indicated that identical populations of bradyrhizobia invaded both composite wild-type plants grown in natural soil. Our results demonstrate that Arachis hairy root is an attractive system for undertaking investigations of the nonclassical features associated with its nitrogen-fixing symbiotic interactions. © 2009 The American Phytopathological Society.

Journal	Data powered by TypesetPlant Cell, Tissue and Organ Culture
Publisher	Data powered by TypesetSpringer Netherlands
ISSN	0167-6857