Effects of plant growth regulators and l-glutamic acid on shoot organogenesis in the halophyte Leymus chinensis (Trin.)

Abstract

The halophyte Leymus chinensis (Trin.) is a perennial rhizome grass (tribe Gramineae) that is widely distributed in China, Mongolia and Siberia, where it is produced as a forage product. In this report, we establish a highly reproducible plant regeneration system through somatic embryogenesis. Two explants, mature seeds and leaf base segments were used; these parts displayed different responses to combinations of growth factors that affect embryogenic callus induction, callus type optimization and plant regeneration. The highest callus induction frequency was obtained on Murashige and Skoog (MS) medium supplemented with 2.0 mg l -1 2,4-dichlorophenoxyacetic acid (2,4-D) in the presence of 5.0 mg l -1 L-glutamic acid. The inclusion of 5.0 mg l -1 L-glutamic acid was found to significantly promote primary callus induction, embryogenic callus formation and callus status improvement. Subculturing on maintenance medium for 1-2 months before plant regeneration was found to be essential for the optimization of callus type and the maturation of embryogenic callus. Callus relative water content and growth rate were simultaneously investigated during callus maintenance, and found to possibly be related to callus type. Shoots were differentiated from the embryogenic callus on the optimal medium with MS salts containing 0.2-0.5 mg l -1 a-naphthalene acetic acid (NAA), 2.0 mg l -1 kinetin (Kn) and 2.0 g l -1 casamino acids in 71.0 and 69.2% of wild-type (WT) and Jisheng No.1 (JS) plants, respectively. Plant regeneration was variable depending on NAA levels, and the addition of casamino acids stimulated the maturation of embryogenic callus and plant regeneration. Transferring callus with shoots onto half-strength MS medium resulted in rooting within 1 week. The growth of regenerated plants was also surveyed in the field. This is the first report of plant regeneration through somatic embryogenesis from mature seeds and leaf base segments of L. chinensis.

Osmotic stress stimulates shoot organogenesis in callus of rice (Oryza sativa L.) via auxin signaling and carbohydrate metabolism regulation

“…However, the mechanism of totipotency is still less understood. Many factors affect shoot regeneration in plant tissue culture: such as genotype Glowacha et al 2010;Park et al 2011), exogenous and endogenous hormones (Jiménez 2005;Barreto et al 2010;Sun and Hong 2010;Huang et al 2012), carbon sources (Huang and Liu 1998;Iraqi et al 2005;Huang et al 2006;Silva 2010;Feng et al 2010), and osmotic requirements (Geng et al 2008;Pan et al 2010;Huang et al 2012). Despite many shoot regeneration and transformation protocols developed in rice culture, the regeneration frequency is low and varies highly among cultivars (Al-Khayri et al 1996;Hoque and Mansfied 2004;Khaleda and Al-Forkan 2006;Zhao et al 2011).…”

Recent Advances of In Vitro Embryogenesis of Monocotyledon and Dicotyledon

“…Plant tissue culture of LC has been investigated using nearly all readily available explants such as mature embryos (Liu et al, 2002b;Kim et al, 2005), mature seeds (Cui et al, 1990;Qu et al, 2004;Kim et al, 2005;Wei et al, 2005;Kong et al, 2008;, 2010a, leaf base segments (Liu et al, 2002b;Kim et al, 2005;, 2010a, rhizoma (Gao, 1982;Lu et al, 2009), immature inflorescence , immature spikes (Liu et al, 2002b;Zhang et al, 2007), and root segments ), shown in Table 1. In our previous studies 2010a), mature seed is considered as the optimal explants to induce embryogenic callus, with 56.4 ~ 88.3% of callus induction frequencies.…”

“…In our previous studies 2010a), mature seed is considered as the optimal explants to induce embryogenic callus, with 56.4 ~ 88.3% of callus induction frequencies. Similar results have been observed in reports of Cui et al (1990) and Kim et al (2005) that found mature seeds could produced the highest callus induction frequencies among young rhizome, embryos and leaves as explants, respectively.…”

“…However, their callus induction and plant regeneration frequencies were still not very high. In the following few years, many scientists continued to attempt the optimal tissue culture conditions and explants for in vitro tissue culture of LC (Liu et al, 2002b;Liu et al, 2004;, 2010a, 2010b. Induction of embryogenic calli, considered as the most critical step for the success in plant regeneration, is influenced by genotype, explants type, and medium composition as well as by their interaction (Rachmawati & Anzai, 2006).…”

Molecular cloning and identification of eukaryotic translation initiation factor 1 family genes (eIF1,eIF1AandeIF1B) inLeymus chinensis(Trin.)

“…), a perennial rhizome grass in the Gramineae family, has halophytic ancestors and could be a potential source of halotolerance genes for glycophytic crop plants. [10] This species is widely distributed throughout Northern China, Mongolia and Siberia, [21,22] having intrinsic potential to thrive under environmentally high alkaline-sodic soil conditions (pH 8.5 to 11.5). Due to its good characteristics, L. chinensis has been commonly used to protect the soil from desertification in northern China.…”