The effect of 2,4-dichlorophenoxyacetic acid, benzyl amino purin and cupric sulphate on in vitro propagation system from shoot apices of shoot tiller of hybrid Napier grass (Pennisetum purpureum Schum)

An efficient micropropagation method of hybrid Napier grass (Pennisetum purpureumn Schum) for in vitro plant production and material breeding was established from multiple-shoot clumps (MCS) regeneration system. This system was important for forage breeding system. Shoot apices from shoot-tillers produced MSC on Murashige-Skoog (MS) induction medium containing several combinations of BAP and 2,4-D in induction stage. The addition of 5 μM (v/v) and 50 μM (v/v) CuSO4 were added in best medium for inoculation to proliferate the clump in proliferation/multiplication stage. Plant regeneration was achieved by culturing on solid MS with several combination of medium containing NAA and BAP in regeneration stage. The best results for induction were Murashige-Skoog (MS) induction medium containing 2 mgL−1 BAP and 0.1 mgL−1 2,4-D. The proliferation stage on MS medium containing 5 μM CuSÜ4 effective for proliferation (50% multiple shoot formation). The regeneration stage using 0.1 mgL−1 NAA and 2.0 mgL−1 BAP (51.6% number of shoot can regenerate). All plantlets were successfully grown up in an acclimatization stage. Based on the results, the hybrid Napier grass regeneration via MSC was a stable tissue culture system (no albino plats), which could be applied either for further genetic transformation assay or for alternative supply of nursery plant in the future.

Leaf Epidermis: The Ambiguous Symplastic Domain

The ability to develop secondary (post-cytokinetic) plasmodesmata (PD) is an important evolutionary advantage that helps in creating symplastic domains within the plant body. Developmental regulation of secondary PD formation is not completely understood. In flowering plants, secondary PD occur exclusively between cells from different lineages, e.g., at the L1/L2 interface within shoot apices, or between leaf epidermis (L1-derivative), and mesophyll (L2-derivative). However, the highest numbers of secondary PD occur in the minor veins of leaf between bundle sheath cells and phloem companion cells in a group of plant species designated “symplastic” phloem loaders, as opposed to “apoplastic” loaders. This poses a question of whether secondary PD formation is upregulated in general in symplastic loaders. Distribution of PD in leaves and in shoot apices of two symplastic phloem loaders, Alonsoa meridionalis and Asarina barclaiana, was compared with that in two apoplastic loaders, Solanum tuberosum (potato) and Hordeum vulgare (barley), using immunolabeling of the PD-specific proteins and transmission electron microscopy (TEM), respectively. Single-cell sampling was performed to correlate sugar allocation between leaf epidermis and mesophyll to PD abundance. Although the distribution of PD in the leaf lamina (except within the vascular tissues) and in the meristem layers was similar in all species examined, far fewer PD were found at the epidermis/epidermis and mesophyll/epidermis boundaries in apoplastic loaders compared to symplastic loaders. In the latter, the leaf epidermis accumulated sugar, suggesting sugar import from the mesophyll via PD. Thus, leaf epidermis and mesophyll might represent a single symplastic domain in Alonsoa meridionalis and Asarina barclaiana.

Genome-Wide Identification of Barley Long Noncoding RNAs and Analysis of Their Regulatory Interactions during Shoot and Grain Development

Long noncoding RNAs (lncRNAs) are a class of RNA molecules with gene regulatory functions in plant development and the stress response. Although the number of lncRNAs identified in plants is rapidly increasing, very little is known about their role in barley development. In this study, we performed global identification of barley lncRNAs based on 53 RNAseq libraries derived from nine different barley tissues and organs. In total, 17,250 lncRNAs derived from 10,883 loci were identified, including 8954 novel lncRNAs. Differential expression of lncRNAs was observed in the developing shoot apices and grains, the two organs that have a direct influence on the final yield. The regulatory interaction of differentially expressed lncRNAs with the potential target genes was evaluated. We identified 176 cis-acting lncRNAs in shoot apices and 424 in grains, while the number of trans-acting lncRNAs in these organs was 1736 and 540, respectively. The potential target protein-coding genes were identified, and their biological function was annotated using MapMan ontology. This is the first insight into the roles of lncRNAs in barley development on the genome-wide scale, and our results provide a solid background for future functional studies.

Ignatovia, a new replacement name for Lazarenkoa Ignatov & Ignatova (Leskeaceae, Bryophyta)

A Bryophyte genus Lazarenkoa Ignatov & Ignatova (2019:227), family Leskeaceae Schimp.(1856:109) was described by Ignatov et al. (2019) on the basis of recent morphological and molecular results obtained by the plant species collected from region Primorsky Territory of Russia. Currently, genus Lazarenkoa Ignatov & Ignatova is monotypic having single species Lazarenkoa microphylla Ignatov & Ignatova (2019:227) and endemic to Russia. Unfortunately, this newly described Bryophyte genus Lazarenkoa Ignatov & Ignatova is a later homonym of Ukrainian Ascomycetes fungi genus Lazarenkoa Zerova (1938:170). Genus Lazarenkoa Zerova, is a monotypic with single species Lazarenkoa selaginellae Zerova (1938:170) belonging to the class Dothideomycetes Erikss. & Winka. (1997:5) described from shoot apices of Selaginella sibirica [Milde(1867:262)] Hieron(1900:290).

Callogenesis and in vitro Regeneration of Baru (Dipteryx alata Vog.) Esprouts

The aim of this study was to evaluate the effect of different concentrations of 6-benzylaminopurine (BAP) and naphthalene acetic acid (ANA) on calogenesis and regeneration from baru leaf and apex segments. The explants were obtained from baru plants previously established in vitro from almonds and cauline apices. The leaf segments were placed in Petri dishes containing MS medium (Murashige & Skoog, 1962) with concentrations (0.0, 2.0, 3.0, 4.0 and 5.0 mg L-1) BAP combined with ANA (0.0 and 2.0 mg L-1). The shoot apices were inoculated in test tubes with the same medium using the concentrations (0.0, 0.5, 1.0 and 1.5 mg L-1) BAP combined (0.0 and 0.1 mg L-1) ANA. After 25 days of inoculation, the percentages of callus and texture in leaf explants and apices were evaluated. The number of shoots was also evaluated by the Scott-Knott test at 5% of probability. The most efficient concentration in the formation of callus in leaves was 3.0 mg L-1 BAP + 2.0 mg L-1 ANA (68.88%), at apexes the most efficient concentration was 1.0 mg L-1 BAP without ANA with 100% calogenesis. The most effective concentration was 1.0 mg L-1 BAP without ANA with an average of 1.90 of shoots in relation to the concentrations evaluated.

A novel WD40-repeat protein involved in formation of epidermal bladder cells in the halophyte quinoa

Halophytes are plants that grow in high-salt environments and form characteristic epidermal bladder cells (EBCs) that are important for saline tolerance. To date, however, little has been revealed about the formation of these structures. To determine the genetic basis for their formation, we applied ethylmethanesulfonate mutagenesis and obtained two mutants with reduced levels of EBCs (rebc) and abnormal chloroplasts. In silico subtraction experiments revealed that the rebc phenotype was caused by mutation of REBC, which encodes a WD40 protein that localizes to the nucleus and chloroplasts. Phylogenetic and transformant analyses revealed that the REBC protein differs from TTG1, a WD40 protein involved in trichome formation. Furthermore, rebc mutants displayed damage to their shoot apices under abiotic stress, suggesting that EBCs may protect the shoot apex from such stress. These findings will help clarify the mechanisms underlying EBC formation and function.

In vitro regeneration of Moringa oleifera Lam.: A medicinal tree of family Moringaceae

A protocol is developed for somatic embryogenesis and organogenesis from nodal segments and shoot-apices of Moringa oleifera Lam. Callusing and multiple shoots induction occurred in nodal segments (0.5-1.0 cm) after 2 weeks of culture on Woody Plant Medium, 1981 (WPM) containing N6-benzyladenine (BA), alone or in combinations with various concentrations of á-naphthalene acetic acid (NAA). The concentration of BA at 4.44 μM was found optimum for multiple shoots formation, resulting in 3.22 ± 0.17 shoots per explants. WPM was enriched by adding certain additives to minimize yellowing and shedding of leaves in proliferated shoots. Maximum roots induction (86.6%) was observed in enriched WPM containing 2.46 μM IBA. Somatic embryos were developed from the calli obtained from nodal segments on enriched WPM supplemented with IBA and BA. Histological studies were carried out for studying the pattern of somatic embryogenesis. Multiple shoots formed from shoot apices (1.0-1.5 cm) cultured on enriched WPM (with or without IBA) after 2 weeks of culture. Root induction occurred simultaneously. The regenerated plantlets were gradually transferred to half strength and later to quarter strength liquid WPM, for 10 days, before transferring to pots. Approximately, 70% survival rate was recorded from in vitro grown plantlets on transfer to pots. Somatic embryogenesis in M. oleifera from nodal explants is reported for the first time in this communication.