Abstract
A healthy root system is vital for tissue culture plantlet survival and rapid adaptation from the in vitro microenvironment to glasshouse conditions. Optimization of the root induction medium is an effective way to promote root induction and elongation. Levels of three auxins (α-naphthaleneacetic acid [NAA], 3-indoleacetic acid [IAA], and 3-indolebutyric acid [IBA]) and copper sulfate (CuSO4) have been investigated in a series of experiments with a sorghum inbred line, Tx430. Significant improvement in root proliferation and shoot growth were observed on Murashige and Skoog (MS) medium supplemented with 1 μmol/L CuSO4, 1 mg/L NAA, 1 mg/L IAA, and 1 mg/L IBA. On average, one explant (the original in vitro-derived shoot) of Tx430 regenerated 56.7 roots, which was 20-fold higher on the optimal medium than on MS control medium. Another tested genotype SA281 showed similar response patterns as Tx430 across media. In addition, 100% of Tx430 and SA281 plantlets originating from the optimized root induction medium all survived after being transferred to potting soil in the glasshouse. The results demonstrate that a combination of auxins (NAA, IAA, and IBA) and CuSO4 together at optimal concentrations provide additive effects on promoting root proliferation and explant growth of in vitro sorghum in root induction medium, and subsequently resulted in 100% survival rate of plantlets ex tissue culture. Compared with two published and frequently used root induction media, the optimized medium significantly enhanced root induction and plantlet growth.
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References
Arnon DI (1949) Copper enzymes in isolated chloroplasts-polyphenoloxidse in Beta vulgaris. Plant Physiol 24:1–15
Bhat S, Kuruvinashetti MS (1995) Callus induction and plantlet regeneration from immature embryos of maintainer (B) lines of Kharit sorghum. J Maharashtra Agric Univ 20:159
De Klerk GJ, Ter Brugge J, Marinova S (1997) Effectiveness of indoleacetic acid, indolebutyric acid and naphthaleneacetic acid during adventitious root formation in vitro in Malus ‘Jork 9’. Plant Cell Tiss Organ Cult 49:39–44
Duncan RR, Waskom RM, Nabors MW (1995) In vitro screening and field evaluation of tissue-culture-regenerated sorghum [Sorghum bicolor (L.) moench] for soil stress tolerance. Euphytica 85:373–380
Elkonin LA, Lopushanskaya RF, Pakhomova NV (1995) Initiation and maintenance of friable, embryogenic callus of sorghum [Sorghum biocor (L) Moench] by amino acids. Maydica 40:153–157
Elkonin LA, Pakhomova NV (2000) Influence of nitrogen and phosphorus on induction embryogenic callus of sorghum. Plant Cell Tiss Organ Cult 61:115–123
Emani C, Sunilkumar G, Rathore KS (2002) Transgene silencing and reactivation in sorghum. Plant Sci 162:181–192
Gao Z, Jayaraj J, Muthukrishnan S, Claflin L, Liang GH (2005a) Efficient genetic transformation of Sorghum using a visual screening marker. Genome 48:321–333
Gao Z, Xie X, Ling Y, Muthukrishnan S, Liang GH (2005b) Agrobacterium tumefaciens-mediated sorghum transformation using a mannose selection system. Plant Biotechnol J 3:591–599
Grootboom AW, Mkhonza NL, O’Kennedy MM, Chakauya E, Kunert K, Chikwamba RK (2010) Biolistic mediated sorghum (Sorghum bicolor L. Moench) transformation via mannose and bialaphos based selection systems. Int J Bot 6:1811–9719
Grootboom AW, O’Kennedy MM, Mkhonza NL, Kunert K, Chakauya E, Chikwamba RK (2008) In vitro culture and plant regeneration of sorghum genotypes using immature zygotic embryos as explant source. Int J Bot 4:450–455
Gurel S, Gurel E, Kaur R, Wong J, Meng L, Tan H-Q, Lemaux PG (2009) Efficient, reproducible Agrobacterium-mediated transformation of sorghum using heat treatment of immature embryos. Plant Cell Rep 28:429–444
Joshi A, Kothari SL (2007) High copper levels in the medium improves shoot bud differentiation and elongation from the cultured cotyledons of Capsicum annuum L. Plant Cell Tiss Organ Cult 88:127–133
Laidlaw HKC (2005) Investigating the sorghum transformation system and transgenic disease resistance. PhD dissertation, School of Agriculture and Food Sciences The University of Queensland, Brisbane Australia pp 166–172
Liu GQ, Godwin ID (2012) Highly efficient sorghum transformation. Plant Cell Rep 31:999–1007
Ma HT, Gu MH, Liang GH (1987) Plant regeneration from cultured immature embryos of Sorghum bicolor (L) moench. Theor Appl Genet 73:389–394
Maralappanavar MS, Kuruvinashetti MS, Harti CC (2000) Regeneration, establishment and evaluation of somaclones in Sorghum bicolor (L.) Moench. Euphytica 115:173–180
Murashige T, Skoog F (1962) A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol Plant 15:473–497
Nirwan RS, Kothari SL (2003) High copper levels improve callus induction and plant regeneration in Sorghum bicolor (L.) Moench. In Vitro Cell Dev Biol Plant 39:161–164
Nirwan RS, Kothari SL (2004) High frequency shoot organogenesis in Sorghum bicolor (L.) Moench. J Plant Biochem Biotechnol 13:149–152
Pola S, Mani NS, Ramana T (2008) Plant tissue culture studies in Sorghum bicolor: immature embryo explants as the source material. Int J Plant Prod 2:1–14
Purnhauser L, Gyulai G (1993) Effect of copper on shoot and root regeneration in wheat, triticale, rape and tobacco tissue cultures. Plant Cell Tiss Organ Cult 35:131–139
Raghuwanshi A, Birch RG (2010) Genetic transformation of sweet sorghum. Plant Cell Rep 29:997–1005
Sadia B, Josekutty PC, Potlakayala SD, Patel P, Goldman S, Rudrabhatla SV (2010) An efficient protocol for culturing meristems of sorghum hybrids. Phyton Int J Exp Bot 79:177–181
Sato S, Clemente T, Dweikat I (2004) Identification of an elite sorghum genotype with high in vitro performance capacity. In Vitro Cell Dev Biol Plant 40:57–60
Sinha A, Jain R, Kachhwaha S, Kothari SL (2010) Optimization of the level of micronutrient copper in the culture medium improves shoot bud regeneration in Indian ginseng [Withania somnifera (L.) Dunal]. Nat Acad Sci Lett India 33:11–16
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We wish to thank the Australian Research Council (ARC) and Pacific Seeds Pty. Ltd. for their financial support on Linkage project LP0883808. We are grateful to Dr. Bradley Campbell and Dr. Yue Sun for their efforts during the editing process.
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Liu, G., Gilding, E.K. & Godwin, I.D. Additive effects of three auxins and copper on sorghum in vitro root induction. In Vitro Cell.Dev.Biol.-Plant 49, 191–197 (2013). https://doi.org/10.1007/s11627-012-9488-2
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DOI: https://doi.org/10.1007/s11627-012-9488-2