VEGETOS: An International Journal of Plant Research & Biotechnology
(Society For Plant Research)

Research Articles


Volume: 33, Issue: 4, December 2020

Print ISSN : 0970-4078.
Online ISSN : 2229-4473.
Pub Email:
Page Visits: 310

Doi: 10.1007/s42535-020-00159-w
Doi Link:
First Page: 690
Last Page: 702
Published: 07 September, 2020

Indole acetic acid (IAA) producing endophytic bacteria on direct somatic embryogenesis and plant regeneration of Exacum travancoricum Bedd.


Endophytic bacteria were isolated from Withania somnifera (L.) Dunal and their potentials were explored through the in vitro plant regeneration techniques. Initially, indole acetic acid (IAA), phosphate solubilization and siderophore producing isolates were screened out. These isolates were identified using molecular tools like 16s rRNA gene sequences namely Bacillus pumilus AS02, Sphingobacterium thalpophilum AS34, Pseudomonas aeruginosa AS36, Agrobacterium tumefaciens AS38 and Enterobacter aerogenes AS75. Further, the regeneration efficacy of IAA producing endophytic bacteria has been analysed on an endangered plant—Exacum travancoricum Bedd. The leaf and inter-node explants of E. travancoricum with or without bacterial infection were tested on Murashige and Skoog’s (MS) medium encompassing 6-benzyladenine (BA; 2.0 mg L− 1) and l-tryptophan (0.2%; w/v). Somatic embryo induction was observed on both explants. The leaf explants infected with S. thalpophilum AS34, P. aeruginosa AS36 and E. aerogenes AS75 exhibited highest percentage of somatic embryo induction (93.3%) compared with the inter-node explants (86.6%). The explants without bacterial infection (control) and the presence of exogenous IAA exhibited lower level of response (88.8%, leaf and 75.5%, inter-node). Histological analysis revealed the appearance of globular embryogenic masses on epidermal, sub-epidermal regions of both explants. The development of torpedo, cotyledon stage and protoderm formation without the vascular connection from explants confirmed direct somatic embryogenesis. This was confirmed with scanning electron microscopy. Sub-culturing of cotyledon somatic embryos in MS liquid medium without growth regulators was performed to obtain well developed shoots with roots.



Indole acetic acid, Endophytic bacteria, 16s rRNA gene sequence, Protoderm, Somatic embryos, n Withania somniferan , n Exacum travancoricumn


  1. Abreu-Tarazi MF, Navarrete AA, Andreote FD, Almeida CV, Tsai SM, Almeida M (2010) Endophytic bacteria in long-term in vitro cultivated ‘‘axenic’’ pineapple microplants revealed by PCR–DGGE. World J Microbiol Biotechnol 26:555–560

  2. Afzal I, Iqrar I, Shinwari ZK, Yasmin A (2017) Plant growth-promoting potential of endophytic bacteria isolated from roots of wild Dodonaea viscose L. Plant Growth Regul 81:399–408

  3. Ahemad M, Khan MS (2010) Phosphate-solubilizing and plant-growth-promoting Pseudomonas aeruginosa PS1 improves Greengram performance in Quizalafop-p-ethyl and clodinafop amended soil. Arch Environ Contam Toxicol 58:361–372

  4. Ahmed I, Ehsan M, Sin Y, Paek J, Khalid N, Hayat R, Chang YH (2014) Sphingobacterium pakistanensis sp. nov., a novel plant growth promoting rhizobacteria isolated from rhizosphere of Vigna mungo. Anton Van Leeuwen 105:325–333

  5. Armstrong TA, Metz SG, Mascia PN (1987) Two regeneration system for the production of haploid plants from wheat anther culture. Plant Sci 51:231–237

  6. Aslam A, Mohamed Rafi K, Kathiravan K, Shajahan A (2010) Class-based stratification matrix for physical leaf traits in phenetic relations of Withania somnifera (L.) Dunal accessions. Plant Syst Evol 288:99–111

  7. Ausubel FM, Brent R, Kingston RE, Moore DD, Seidman JG, Smith JA, Struhl K (1995) Short protocols in molecular biology, Ch 2.4. Wiley, New York

  8. Barker SJ, Tagu D (2000) The roles of auxins and cytokinins in mycorrhizal symbioses. J Plant Growth Regul 19:144–154

  9. Benson A, Joe MM, Karthikeyan B, Sa T, Rajasekaran C (2014) Role of Achromobacter xylosoxidans AUM54 in Micropropagation of Endangered Medicinal Plant Naravelia zeylanica (L.) DC. J Plant Growth Regul 33:202–213

  10. Berg G, Krechel A, Ditz M, Sikora RA, Ulrich A, Hallmann J (2005) Endophytic and ectophytic potato-associated bacterial communities differ in structure and antagonistic function against plant pathogenic fungi. FEMS Microbiol Ecol 51:215–229

  11. Bertrand H, Nalin R, Bally R, Marel JCC (2001) Isolation and identification of the most efficient plant growth promoting bacteria associated with canola. Biol Fertil Soil 33:152–156

  12. Burdyn L, Luna C, Tarragó J, Sansberro P, Dudit N, González A, Mroginski L (2006) Direct shoot regeneration from leaf and internode explants of Aloysia polystachya (Gris.) Mold. (Verbebaceae). In Vitro Cell Dev Biol Plant 42:235–239

  13. Chen JT, Chang WC (2006) Direct somatic embryogenesis and plant regeneration from leaf explants of Phalaenopsis amabilis. Biol Plant 50:169–173

  14. Chen L, Luoa S, Xiao X, Guo H, Chen J, Wan Y, Li B, Xu T, Xi Q, Rao C, Liu C, Zeng G (2010) Application of plant growth-promoting endophytes (PGPE) isolated from Solanum nigrum L. for phytoextraction of Cd-polluted soils. Appl Soil Ecol 46:383–389

  15. Chopade BA, Huddedar SB, Shete AM, Tilekar JN, Gore SD, Dhavale DD (2008) Plasmid encoding IAA and method thereof. US Pat 7(341):868

  16. Cooke TJ, Racusen RH, Cohen JD (1993) The role of auxin in plant embryogenesis. Plant Cell 5:1494–1495

  17. D’Alessandro M, Erb M, Ton J, Brandenburg A, Karlen D, Zopfi J, Turlings TCJ (2014) Volatiles produced by soil-borne endophytic bacteria increase plant pathogen resistance and affect tritrophic interactions. Plant Cell Environ 37:813–826

  18. Dai J-L, Tan X, Zhan Y-Q, Xiao S, Gao Y, Xu D-W, Wang T, Wang X-C, You X-L (2011) Rapid and repetitive plant regeneration of Aralia elata Seem. Via somatic embryogenesis. Plant Cell Tissue Organ Cult 104:125–130

  19. Dam A, Paul S, Bandyopadhyay TK (2010) Direct somatic embryogenesis and plant regeneration from leaf explants of Limonium sinensis (Girard) Kuntze. Sci Hortic 126:253–260

  20. Das J, Mao AA, Handique PJ (2013) Callus-mediated organogenesis and effect of growth regulators on production of different valepotriates in Indian valerian (Valeriana jatamansi Jones.). Acta Physiol Plant 35:55–63

  21. de Almeida CV, Andreote FD, Yara R, Tanaka FAO, Azevedo JL, de Almeida M (2009) Bacteriosomes in axenic plants: endophytes as stable endosymbionts. World J Microbiol Biotechnol 25:1757–1764

  22. Dias ACF, Costa FEC, Andreote FD, Lacava PT, Teixeira MA, Assumpção LC, Araújo WL, Azevedo JL, Melo IS (2009) Isolation of micropropagated strawberry endophytic bacteria and assessment of their potential for plant growth promotion. World J Microbiol Biotechnol 25:189–195

  23. Donnarumma F, Capuana M, Vettori C, Petrini G, Giannini R, Indorato C, Mastromei G (2011) Isolation and characterization of bacterial colonies from seeds and in vitro cultures of Fraxinus spp. from Italian sites. Plant Biol 13:169–176

  24. Elangomathavan R, Prakash S, Kathiravan K, Seshadri S, Ignacimuthu S (2006) Plant regeneration through micropropagation from nodal explants of critically endangered and endemic plant Exacum travancoricum Bedd. J Plant Biotech 8:51–55

  25. Esposito-Polesi NP, de Andrade PAM, de Almeida CV, Andreote FD, Almeida M (2015) Endophytic bacterial communities associated with two explant sources of Eucalyptus benthamii Maiden & Cambage. World J Microbiol Biotechnol 31:1737–1746

  26. Fehér A (2005) Why somatic plant cells start to form embryos? In: Mujib A, Samaj J (eds) Somatic embryogenesis. Springer, Berlin, pp 85–101

  27. Fischer C, Neuhaus G (1996) Influence of auxin on the establishment of bilateral symmetry in monocots. The Plant J 9:659–669

  28. Frankenberger WT, Arshad M (1995) Phytohormones in soils: microbial production and function. Marcel Dekker Inc, New York

  29. Frim J, Vieten A, Bauer M, Weijers D, Schwarz H, Haman T, Offringa R, Jürgens G (2003) Efflux-dependent auxin gradients establish the apical-basal axis of Arabidopsis. Nature 426:147–153

  30. Gardner JM, Feldman AW, Zablotowicz M (1982) Identity and behavior of xylem-residing bacteria in rough lemon roots of Florida citrus trees. Appl Env Microbiol 43:1335–1342

  31. Goldstein AH (1986) Bacterial solublization of mineral phosphate: Historical perspective and future prospects. Am J Alter Agric 1:51–57

  32. Gopalan R, Hendry AN (2000) Endemic plants of India: CAMP for strict endemics of Agasthyamalai hills, Southern Western Ghats. Bishen Singh Mahendra Pal Singh Publishers, Dehra Dun

  33. Gravel V, Antoun H, Tweddell RJ (2007) Growth stimulation and fruit yield improvement of greenhouse tomato plants by inoculation with Pseudomonas putida or Trichoderma atroviride: possible role of indole acetic acid (IAA). Soil Biol Biochem 39:1968–1977

  34. Hallmann J, Quadt-Hallmann A, Mahaffee WF, Kloepper JW (1997) Bacterial endophytes in agricultural crops. Can J Microbiol 43:895–914

  35. Hardoim PR, van Overbeek LS, van Elsas JD (2008) Properties of bacterial endophytes and their proposed role in plant growth. Cell 16:463–471

  36. Hayakawa M, Nonomura H (1987) Humic acid vitamin agar, a new medium for selective isolation of soil actinomycetes. J Ferment Tech 65:501–509

  37. Henning K, Villforth F (1940) Experimentelle untersuchungen zur frage der bacteriesymbiose in höheren pflanzen und ihre beeinflussung durch ‘Leitemente.’ Biochem Zeitschr 305:299–309

  38. Iantcheva A, Vlahova M, Bakalova E, Kondorosi E, Elliott MC, Atanassov A (1999) Regeneration of diploid annual medics via direct somatic embryogenesis promoted by thidiazuron and banzylaminopurine. Plant Cell Rep 18:904–910

  39. Jacobs MJ, Bugbee WM, Gabrielson DA (1985) Enumeration, location, and characterization of endophytic bacteria within sugar beet roots. Can J Bot 63:1262–1265

  40. Jasim B, Jimtha CJ, Jyothis M, Radhakrishnan EK (2013) Plant growth promoting potential of endophytic bacteria isolated from Piper nigrum. Plant Growth Regul 71:1–11

  41. Ji SH, Gururani MA, Chun S-C (2013) Isolation and characterization of plant growth promoting endophytic diazotrophic bacteria from Korean rice cultivars. Microbiol Res 169:83–98

  42. Jimtha JC, Smitha PV, Anisha C, Deepthi T, Meekha G, Radhakrishnan EK, Gayatri GP, Remakanthan A (2014) Isolation of endophytic bacteria from embryogenic suspension culture of banana and assessment of their plant growth promoting properties. Plant Cell Tissue Organ Cult 118:57–66

  43. Kannan P, Premkumar A, Ignacimuthu S (2007) Thidiazuron induced shoot regeneration in the endangered species, Exacum travancoricum Beedi. Indian J Biotech 6:564–566

  44. Karadeniz A, Topcuoğlu SF, İnan S (2006) Auxin, gibberellin, cytokinin and abscisic acid production in some bacteria. World J Microbiol Biotechnol 22:1061–1064

  45. Khan T, Reddy VS, Leelavathi S (2010) High-frequency regeneration via somatic embryogenesis of an elite recalcitrant cotton genotype (Gossypium hirsutum L.) and efficient Agrobacterium-mediated transformation. Plant Cell Tissue Organ Cult 101:323–330

  46. Kumar A, Kaul MK, Bhan MK, Khanna PK, Suri KA (2007) Morphological and chemical variation in 25 collections of the Indian medicinal plant, Withania somnifera (L.) Dunal (Solanaceae). Genet Resour Crop Evol 54:655–660

  47. Larraburu EE, Carletti SM, C´aceres EAR, Llorente BE (2007) Micropropagation of photinia employing rhizobacteria to promote root development. Plant Cell Rep 26:711–717

  48. Lee S, Flores-Encarnacion M, Contreras-Zentella M, Garcia-Flores L, Escamilla JE, Kennedy C (2004) Indole-3-acetic acid biosynthesis is deficient in Gluconacetobacter diazotrophicus strains with mutations in cytochrome C biogenesis genes. J Bacteriol 186:5384–5391

  49. Li JH, Wang ET, Chen WF, Chen WX (2008) Genetic diversity and potential for promotion of plant growth detected in nodule endophytic bacteria of soybean grown in Heilongjiang province of China. Soil Biol Biochem 40:238–246

  50. Liaqat F, Eltem R (2016) Identification and characterization of endophytic bacteria isolated from in vitro cultures of peach and pear rootstocks. 3 Biotech 6:120

  51. Lima JVL, Weber OB, Correia D, Soares MA, Senabio JA (2014) Endophytic bacteria in cacti native to a Brazilian semi-arid Region. Plant Soil 389:25–33

  52. Mahendran G, Narmatha Bai V (2012) Direct somatic embryogenesis and plant regeneration from seed derived protocorms of Cymbidium bicolor Lindl. Sci Hortic 135:40–44

  53. Mathesius U, Schlaman HRM, Spaink HP, Sautter C, Rolfe BG, Djordjevic MA (1998) Auxin transport inhibition precedes root nodule formation in white clover roots and is regulated by flavonoids and derivatives of chitin oligosaccharides. Plant J 14:23–34

  54. Mendes R, Pizzirani-Kleiner AA, Araujo WL, Raaijmakers JM (2007) Diversity of cultivated endophytic bacteria from sugarcane: genetic and biochemical characterization of Burkholderia cepacia complex isolates. Appl Environ Microbiol 73:7259–7267

  55. Michalczuk L, Cooke TJ, Cohen JD (1992) Auxin levels at different stages of carrot somatic embryogenesis. Phytochemistry 31:1097–1103

  56. Michalczuk L, Ribnicky DM, Cooke TJ, Cohen JD (1992) Regulation of indole-3-acetic acid biosynthetic pathways in carrot cell cultures. Plant Physiol 100:1346–1353

  57. Misaghi IJ, Donndelinger CR (1990) Endophytic bacteria in symptom-free cotton plants. Phytopathology 80:808–811

  58. Morris RO (1986) Genes specifying auxin and cytokinin biosynthesis in phytopathogens. Annu Rev Plant Physiol 37:509–538

  59. Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassay with tobacco tissue culture. Physiol Plant 15:473–497

  60. Nautiyal CS (1999) An efficient microbiological growth medium for screening phosphate solubilising microorganisms. FEMS Microbiol Lett 170:265–270

  61. Nowak J (1998) Benefits of in vitro “Biotization” of plant tissue cultures with microbial inoculants. In Vitro Cell Dev Biol Plant 34:122–130

  62. Nowak J, Shulaev J (2003) Priming for transplant stress resistance in in vitro propagation. In Vitro Cell Dev Biol Plant 39:107–124

  63. Parray JA, Kamili AN, Reshi ZA, Qadri RA, Jan S (2015) Interaction of rhizobacterial strains for growth improvement of Crocus sativus L. under tissue culture conditions. Plant Cell Tissue Organ Cult 121:325–334

  64. Pati PK, Kaur J, Singh P (2011) A liquid culture system for shoot proliferation and analysis of pharmaceutically active constituents of Catharanthus roseus (L.) G. Don. Plant Cell Tissue Organ Cult 105:299–307

  65. Patil HJ, Srivastava AK, Kumar S, Chaudhari BL, Arora DK (2010) Selective isolation, evaluation and characterization of antagonistic actinomycetes against Rhizoctonia solani. World J Microbiol Biotechnol 26:2163–2170

  66. Perotti R (1926) On the limits of biological inquiry on soil science. Proc Int Soc Soil Sci 2:146–161

  67. Praveen N, Murthy HN (2011) Effects of macroelements and nitrogen source on biomass accumulation and withanolide-A production from cell suspension cultures of Withania somnifera (L.) Dunal. Plant Cell Tissue Organ Cult 104:119–124

  68. Quambusch M, Brümmer J, Haller K, Winkelmann T, Bartsch M (2016) Dynamics of endophytic bacteria in plant in vitro culture: quantification of three bacterial strains in Prunus avium in different plant organs and in vitro culture phases. Plant Cell Tissue Organ Cult 126:305–317

  69. Quambusch M, Pirttilä AM, Tejesvi MV, Winkelmann T, Bartsch M (2014) Endophytic bacteria in plant tissue culture: differences between easy- and difficult-to-propagate Prunus avium genotypes. Tree Physiol 34:524–533

  70. Raomai S, Kumaria S, Tandon P (2014) Plant regeneration through direct somatic embryogenesis from immature zygotic embryos of the medicinal plant, Paris polyphylla Sm. Plant Cell Tiss Organ Cult 118:445–455

  71. Rashid S, Charles TC, Glick BR (2012) Isolation and characterization of new plant growth-promoting bacterial endophytes. Appl Soil Ecol 61:217–224

  72. Ravichandran R, Hemaasri S, Cameotra SS, Jayaprakash NS (2015) Purification and characterization of an extracellular uricase from a new isolates of Sphingobacterium thalpophilum (VITPCB5). Prot Express Purif 114:136–142

  73. Remans R, Beebe S, Blair M, Manrique G, Tovar E, Idupulapati R, Croonenborghs A, Torres-Gutierrez R, El-Howeity M, Michiels J, Vanderleyden J (2008) Physiological and genetic analysis of root responsiveness to auxin-producing plant growth promoting bacteria in common bean (Phaseolus vulgaris L.). Plant Soil 302:149–161

  74. Roesch LFW, Quadros PD, Camargo FAO, Triplett EW (2007) Screening of diazotrophic bacteria Azopirillum spp. for nitrogen fixation and auxin production in multiple field sites in southern Brazil. World J Microbiol Biotechnol 23:1377–1383

  75. Rout JR, Sahoo SL (2013) Antioxidant enzyme gene expression in response to copper stress in Withania somnifera L. Plant Growth Regul 71:95–99

  76. Sarethy IP, Kashyap A, Bahal A, Sejwal N, Gabrani R (2014) Study of liquid culture system for micropropagation of the medicinal plant Solanum nigrum L. and its effect on antioxidant property. Acta Physiol Plant 36:2863–2870

  77. Savio LEB, Astarita LV, Santaren ER (2012) Secondary metabolism in micropropagated Hypericum perforatum L. grown in non-aerated liquid medium. Plant Cell Tiss Organ Cult 108:465–472

  78. Schmidt CS, Mrnka L, Frantík T, Lovecká P, Vosátka M (2018) Plant growth promotion of Miscanthus × giganteus by endophytic bacteria and fungi on non-polluted and polluted soils. World J Microbiol Biotech 34:48

  79. Schneider EA, Wightman F (1974) Metabolism of auxin in higher plants. Annu Rev Plant Physiol 25:487–513

  80. Schwyn B, Neilands JB (1987) Universal chemical assay for the detection and determination of siderophores. Anal Biochem 160:47–56

  81. Sgroy V, Cassán F, Masciarelli O, Del Papa MF, Lagares A, Luna V (2009) Isolation and characterization of endophytic plant growth-promoting (PGPB) or stress homeostasis-regulating (PSHB) bacteria associated to the halophyte Prosopis strombulifera. Appl Microbiol Biotechnol 85:371–381

  82. Sharma V, Kamal B, Srivastava N, Negi Y, Dobriyal AK, Jadon VS (2015) Enhancement of in vitro growth of Swertia chirayita Roxb. Ex Fleming co-cultured with plant growth promoting rhizobacteria. Plant Cell Tiss Organ Cult 121:215–225

  83. Shi Y, Lou K, Li C (2009) Isolation, quantity distribution and characterization of endophytic microorganisms within sugar beet. Afr J Biotechnol 8:835–840

  84. Soundar Raju C, Aslam A, Kathiravan K, Palani P, Shajahan A (2014) Direct somatic embryogenesis and plant regeneration from leaf sheath explants of mango ginger (Curcuma amada Roxb.). In Vitro Cell Dev Biol -Plant 50:752–759

  85. Soundar Raju C, Aslam A, Shajahan A (2015) High-efficiency direct somatic embryogenesis and plant regeneration from leaf base explants of turmeric (Curcuma longa L.). Plant Cell Tiss Organ Cult 122:79–87

  86. Spaepen S, Vanderleyden J, Remans R (2007) Indole-3-acetic acid in microbial and microorganism-plant signaling. FEMS Microbiol Rev 31:425–448

  87. Sriskandarajah S, Lundquist P-O (2009) High frequency shoot organogenesis and somatic embryogenesis in juvenile and adult tissues of seabuckthorn (Hippophae rhamnoides L.). Plant Cell Tiss Organ Cult 99:259–268

  88. Szilagyi-Zecchin VJ, Ikeda AC, Hungria M, Adamoski D, Kava-Cordeiro V, Glienke C, Galli-Terasawa LV (2014) Identification and characterization of endophytic bacteria from corn (Zea mays L.) roots with biotechnological potential in agriculture. AMB Exp 4:26

  89. Taurian T, Anzuay MS, Angelini JG, Tonelli ML, Luduena L, Pena D, Ibanez F, Fabra A (2010) Phosphate-solubilizing peanut associated bacteria: screening for plant growth promoting activities. Plant Soil 329:421–431

  90. Thilip C, Soundar Raju C, Varutharaju K, Aslam A, Shajahan A (2015) Improved Agrobacterium rhizogenes-mediated hairy root culture system of Withania somnifera (L.) Dunal using sonication and heat treatment. 3 Biotech 5:949–956

  91. Thomas P, Soly TA (2009) Endophytic bacteria associated with growing shoot tips of banana (Musa sp.) cv. grand naine and the affinity of endophytes to the host. Microb Ecol 58:952–964

  92. Tilkat E, Onay A (2009) Direct shoot organogenesis from in vitro derived mature leaf explants of pistachio. In Vitro Cell Dev Biol Plant 45:92–98

  93. Tilkat E, Onay A, Yıldırım H, Ayaz E (2009) Direct plant regeneration from mature leaf explants of pistachio, Pistacia vera L. Sci Hortic 121:361–365

  94. Tsavkelova EA, Cherdyntseva TA, Botina SG, Netrusov AI (2007) Bacteria associated with orchid roots and microbial production of auxin. Microbiol Res 162:69–76

  95. Tsavkelova EA, Egorova MA, Leontieva MR, Malakho SG, Kolomeitseva GL, Netrusov AI (2016) Dendrobium nobile Lindl. seed germination in co-cultures with diverse associated bacteria. Plant Growth Regul 80:79–91

  96. Turakhia DV, Kulkarni AR (1988) In vitro regeneration from leaf explant of Ladebouria hyacinthiana Roth. (Scilla indica Bak.). Curr Sci 57:214–216

  97. Ulrich K, Stauber T, Ewald D (2008) Paenibacillus-a predominant endophytic bacterium colonising tissue cultures of woody plants. Plant Cell Tiss Organ Cult 93:347–351

  98. Unda F, Kalynyak P, Riseman A (2007) Organogenesis plant regeneration from leaf explants of Exacum Styer Group. Plant Cell Tiss Organ Cult 89:105–111

  99. van Noorden GE, Ross JJ, Reid JB, Rolfe BG, Mathesius U (2006) Defective long-distance auxin transport regulation in the Medicago truncatula super numeric nodules mutant1[W]. Plant Physiol 140:1494–1506

  100. van Overbeek LS, Bergervoet JH, Jacobs FH, van Elsas JD (2004) The Low-Temperature-Induced Viable-But-Non Culturable State Affects the Virulence of Ralstonia solanacearum Biovar 2. Phytopath 94:463–469

  101. Verma SC, Ladha JK, Tripathi AK (2001) Evaluation of plant growth promoting and colonization ability of endophytic diazotrophs from deep water rice. J Biotechnol 91:127–141

  102. Verma SK, Sahin G, Yucesan B, Eker I, Sahbaz N, Gurel S, Gurel E (2012) Direct somatic embryogenesis from hypocotyl segments of Digitalis trojana Ivan and subsequent plant regeneration. Ind Crops Prod 40:76–80

  103. Vestberg M, Kukkonen S, Saari K, Parikka P, Huttunen J, Tainio L, Devos N, Weekers F, Kevers C, Thonart P, Lemoine MC, Cordier C, Alabouvette C, Gianinazzi S (2004) Microbial inoculation for improving the growth and health of micropropagated strawberry. Appl Soil Ecol 27:243–258

  104. Vijaya Chitra DS, Padmaja G (2005) Shoot regeneration via direct organogenesis from in vitro derived leaves of mulberry using thidiazuron and 6-benzylaminopurine. Sci Hortic 106:593–602

  105. Vondráková Z, Eliášová K, Fischerová L, Vágner M (2011) The role of auxins in somatic embryogenesis of Abies alba. Cent Eur J Biol 6:587–596

  106. Yang J, Kloepper JW, Ryu CM (2009) Rhizosphere bacteria help plants tolerate abiotic stress. Trends Plant Sci 14:1–4

  107. Zhang CX, Zhao X, Jing YX, Chida T, Chen H, Shen SH (2008) Phenotypic and biological properties of two antagonist Bacillus subtilis strains. World J Microbiol Biotechnol 24:2179–2181


Acknowledgements :

The authors thank University Grants Commission, New Delhi, for its support through the “College with Potential for Excellence” program.

Author Information:

Chellappan Soundar Raju
Department of Botany, Vivekananda College, Madurai, India
Abubakker Aslam
Department of Botany, Jamal Mohamed College, Tiruchirappalli, India

Devarajan Thangadurai
Department of Botany, Karnatak University, Dharwad, India

Jeyabalan Sangeetha
Department of Environmental Science, School of Earth Science Systems, Central University of Kerala, Kasaragod, India

Krishnan Kathiravan
Department of Biotechnology, University of Madras, Chennai, India

Appakan Shajahan
Department of Botany, Jamal Mohamed College, Tiruchirappalli, India

Pdf Download