Donor Plants Research Articles

Festuca pratensis-like Subgenome Reassembly from a "Chromosomal Cocktail" in the Intergeneric Festulolium (Poaceae) Hybrid: A Rare Chromoanagenesis Event in Grasses.

Festuca and Lolium grass species are used for Festulolium hybrid variety production where they display trait complementarities. However, at the genome level, they show antagonisms and a broad scale of rearrangements. A rare case of an unstable hybrid, a donor plant manifesting pronounced variability of its clonal parts, was discovered in the F2 group of 682 plants of Lolium multiflorum × Festuca arundinacea (2n = 6x = 42). Five phenotypically distinct clonal plants were determined to be diploids, having only 14 chromosomes out of the 42 in the donor. GISH defined the diploids as having the basic genome from F. pratensis (2n = 2x = 14), one of the progenitors of F. arundinacea (2n = 6x = 42), with minor components from L. multiflorum and another subgenome, F. glaucescens. The 45S rDNA position on two chromosomes also corresponded to the variant of F. pratensis in the F. arundinacea parent. In the highly unbalanced donor genome, F. pratensis was the least represented, but the most involved in numerous recombinant chromosomes. Specifically, FISH highlighted 45S rDNA-containing clusters involved in the formation of unusual chromosomal associations in the donor plant, suggesting their active role in karyotype realignment. The results of this study show that F. pratensis chromosomes have a particular fundamental drive for restructuring, which prompts the disassembly/reassembly processes. The finding of F. pratensis "escaping" and rebuilding itself from the chaotic "chromosomal cocktail" of the donor plant points to a rare chromoanagenesis event and extends the view of plant genome plasticity.

Panicle formation order influence in rice Oryza sativa L in vitro androgenesis

A comparative analysis of rice Oryza sativa L. main and lateral panicles in androgenesis in vitro on F1 plants of two hybrid combinations: L×3P and K×3P to increase the number of cultivated anthers during the season was carried out. Donor plants were grown on the growing area in metal vessels filled with soil. The main panicle was used from three L×3P hybrids and one K×3P hybrid, single lateral panicle was cut from six L×3P plants and three K×3P plants. The genotypes number was calculated as the product of the calli number with doubled haploids by 1.25. In vitro culture 2050 anthers were introduced. According to the intensity of callus formation, the number of green regenerants per callus, and the doubled haploids proportion, there were no statistically significant differences between the main and lateral panicles in the L×3P combination. In total, 215 doubled haploids lines of twenty nine genotypes were obtained, which is theoretically sufficient for breeding a new variety. On the hybrid combination K×3P, 120 doubled haploids of five genotypes were formed from one donor plant with the main panicle. There were no statistically significant differences between the main and lateral panicles. It is concluded that it is expedient to use lateral rice panicles in vitro androgenesis to create the initial breeding material. Their use makes it possible to distribute labor force over time and increase the total volume of anthers cultivated in vitro, and, ultimately, the doubled haploids number and variability of one sample. In the time absence and other restrictions, it is preferable to use the main panicle.

Genetic stability of lavender (Lavandula angustifolia Mill.) plants obtained during long-term clonal micropropagation

The aim of the study was to evaluate the genetic stability of lavender cultivars during long-term clonal micropropagation using RAPD and ISSR markers. The material for the study was three lavender (Lavandula angustifolia Mill.) cultivars of the Crimean breeding - ‘Vdala', ‘Sineva', ‘Stepnaya'. The biological objects were the original donor plants (grown under controlled conditions), as well as microshoots after 6 and 16 subcultivations during in vitro propagation. We used two RAPD (OPA 10, OPO 13) and four ISSR primers (HB 13, HB 15, ISSR 1, ISSR 2, ISSR 3). It was not found significant differences on the number and length of shoots, the number of nodes on the shoot and the multiplication index after 6 and 16 subcultivations for all cultivars. According to the morphology, the microshoots of the three studied cultivars after different periods cultivation also did not differ from each other. Using 7 markers, we identified 62 loci. All primers used in the work were polymorphic (41.7...88.9%), and the amplification products reliably identified lavender cultivars. The length of the amplified fragments varied from 378 to 2177 base pairs. The microshoots, obtained using clonal micropropagation after 6 and 16 subcultivations, were identical in genetic profile to the original lavender cultivars. As a result, the possibility of long-term (at least 16 subcultivations) micropropagation of lavender was shown, while maintaining their genetic stability.

New Paradigms in Brassinosteroids, Strigolactones, Sphingolipids, and Nitric Oxide Interaction in the Control of Lateral and Adventitious Root Formation.

The root system is formed by the primary root (PR), which forms lateral roots (LRs) and, in some cases, adventitious roots (ARs), which in turn may produce their own LRs. The formation of ARs is also essential for vegetative propagation in planta and in vitro and for breeding programs. Root formation and branching is coordinated by a complex developmental network, which maximizes the plant's ability to cope with abiotic stress. Rooting is also a response caused in a cutting by wounding and disconnection from the donor plant. Brassinosteroids (BRs) are steroid molecules perceived at the cell surface. They act as plant-growth-regulators (PGRs) and modulate plant development to provide stress tolerance. BRs and auxins control the formation of LRs and ARs. The auxin/BR interaction involves other PGRs and compounds, such as nitric oxide (NO), strigolactones (SLs), and sphingolipids (SPLs). The roles of these interactions in root formation and plasticity are still to be discovered. SLs are carotenoid derived PGRs. SLs enhance/reduce LR/AR formation depending on species and culture conditions. These PGRs possibly crosstalk with BRs. SPLs form domains with sterols within cellular membranes. Both SLs and SPLs participate in plant development and stress responses. SPLs are determinant for auxin cell-trafficking, which is essential for the formation of LRs/ARs in planta and in in vitro systems. Although little is known about the transport, trafficking, and signaling of SPLs, they seem to interact with BRs and SLs in regulating root-system growth. Here, we review the literature on BRs as modulators of LR and AR formation, as well as their crosstalk with SLs and SPLs through NO signaling. Knowledge on the control of rooting by these non-classical PGRs can help in improving crop productivity and enhancing AR-response from cuttings.

DYNAMIC OF INDOLE ALKALOIDS IN A SOIL AND ITS RELATIONSHIPS WITH ALLELOPATHIC PROPERTIES

Allelopathy is one of the alternatives used for integrated weed management (IWM), in order to minimize the use of synthetic herbicides. Allelopathy is defined as the effect produced by a chemical released by a donor plant on the development of another competitive recipient plant.

Allelopathy activity under laboratory, greenhouse and field conditions: A review

<abstract> <p>Weeds are one of the significant problems that impact agriculture production. Farmers have been using synthetic herbicides to control weed infestations in the field. However, the excessive usage of herbicides has led to various environmental concerns, including the emergence of herbicide resistant weeds. Allelopathy is an environment-friendly alternative that can control weeds. Here, we performed a systematic literature review to assess the potential and effects of allelopathy under laboratory, greenhouse and field conditions. Articles were collected by searching the SCOPUS database and guided by PRISMA. Of 371 studies identified, forty-three articles used allelopathy to control weeds under greenhouse and field conditions, with Poaceae being the prominent family studied as donor plants. Six articles reported up to 80% weed growth suppression when spraying allelopathy extract under greenhouse conditions, while mulch and soil incorporated with donor plants contributed over 50% suppression under field conditions. The findings revealed that 20 studies had conducted metabolite identification to determine the allelochemicals with phytotoxic activity against target plants. However, the mechanism of allelopathy was not thoroughly investigated. In conclusion, we found an increasing trend of allelopathy experiments conducted under greenhouse and field conditions. Furthermore, field trials should be included to validate laboratory data and to provide insight into allelochemical action and its relationship with the environment.</p> </abstract>

Effect of Pollination with Gamma Irradiated Pollen on In Vitro Regeneration of Ovule Culture in Cyclamen

The obtention of homozygous lines through in situ parthenogenesis via gamma irradiation method is a comprehensive application in vegetables. However, there are a limited number of studies on in situ parthenogenesis in ornamentals. Therefore, in situ parthenogenetic capacity of more species needs to be examined. For this purpose, the effects of pollination with gamma-irradiated pollen on in vitro ovule cultured in Cyclamen persicum L. were evaluated in this study. Flower buds were collected before anthesis and irradiated at different doses 50, 100, 150, 200, 300, and 450 Gy of gamma-ray using a Co-60 source. The control group was pollinated with non-irradiated pollen. Fruits were harvested 30 days after pollination, and isolated ovule explants were cultured on four different mediums in in vitro. M0 was control group containing half-strength MS basal media; M1 media additionally has 10 g/L maltose, 1.0 g/L proline, 2.0 g/L peptone, 200.0 mg/L spermidine and 0.5 mg/L kinetin; in addition to basal medium, M2 media additionally contains 10 g/L maltose, 1.0 g/L proline, 2.0 g/L peptone, 200.0 mg/L spermidine, 0.4 mg/L gibberellic acid (GA3) and 0.4 mg/L N6-benzyl adenine (BA). M3 media additionally contains 2.0 mg/L 2,4-D and 0.8 mg/L 6-( γ, γ-dimethylallylamino) purine (2iP). Plantlets started to form 10-12 weeks after the beginning of culture. The effects of nutrient media, irradiation dose, and their interactions on plant formation were statistically significant. The lowest plantlet regeneration (0.33%) was obtained from ovule explants exposed to 50 Gy gamma rays and cultured on M3 media while the highest plantlet regeneration (2.66%) was obtained from ovule explants cultured on M1 media 30 days after pollination with non-irradiated pollen grains. According to stomatal observations, there were no statistical differences between donor plant and in vitro regenerated plantlets.

Genetic requirements for infection-specific responses in conferring disease resistance in Arabidopsis.

Immunity in plants arises from defense regulatory circuits that can be conceptualized as modules. Both the types (and isolates) of pathogen and the repertoire of plant receptors may cause different modules to be activated and affect the magnitude of activation. Two major defense enzymes of Arabidopsis are ALD1 and ICS1/SID2. ALD1 is an aminotransferase needed for producing the metabolites pipecolic acid, hydroxy-pipecolic acid, and possibly other defense signals. ICS1/SID2 produces isochorismate, an intermediate in the synthesis of salicylic acid (SA) and SA-derivatives. Metabolites resulting from the activation of these enzymes are found in petiole exudates and may serve as priming signals for systemic disease resistance in Arabidopsis. Mutants lacking ALD1 are known to have reduced SA accumulation. To further investigate the role of ALD1 in relation to the SA-related module, immunity phenotypes of double mutants that disrupt ALD1 and ICS1/SID2 or SA perception by NPR1 were compared with each single mutant after infection by different Pseudomonas strains. Exudates collected from these mutants after infection were also evaluated for their ability to confer disease resistance when applied to wild-type plants. During infection with virulent or attenuated strains, the loss of ALD1 does not increase the susceptibility of npr1 or sid2 mutants, suggesting the main role of ALD1 in this context is in amplifying the SA-related module. In contrast, after an infection that leads to strong pathogen recognition via the cytoplasmic immune receptor RPS2, ALD1 acts additively with both NPR1 and ICS1/SID2 to suppress pathogen growth. The additive effects are observed in early basal defense responses as well as SA-related events. Thus, there are specific conditions that dictate whether the modules independently contribute to immunity to provide additive protection during infection. In the exudate experiments, intact NPR1 and ICS1/SID2, but not ALD1 in the donor plants were needed for conferring immunity. Mixing exudates showed that loss of SID2 yields exudates that suppress active exudates from wild-type or ald1 plants. This indicates that ICS1/SID2 may not only lead to positive defense signals, but also prevent a suppressive signal(s).

Novel Cognitions in Allelopathy: Implications from the "Horizontal Natural Product Transfer".

Whereas the translocation of allelochemicals between plants is well established, a related general transfer of genuine specialized metabolites has not been considered so far. The elucidation of the so-called "Horizontal Natural Product Transfer" revealed that alkaloids, such as nicotine and pyrrolizidine alkaloids, which are leached out from decomposing alkaloid-containing plants (donor plants), are indeed taken up by the roots of plants growing in the vicinity (acceptor plants). Further studies demonstrated that phenolic compounds, such as coumarins or stilbenes, are also taken up by acceptor plants. Contemporary analyses from co-cultivation experiments outlined that natural products are not exclusively transferred from dead and rotting donor plant materials, but also from vital plants. In analogy to xenobiotics, the imported specialized metabolites might also be modified within the acceptor plants. As known from the uptake of xenobiotics, the import of specialized metabolites is also generally due to a simple diffusion of the substances across the biomembranes and does not require a carrier. The uptake depends in stricto sensu on the physicochemical properties of the certain compound. This article presents a current overview of the phenomenon of "Horizontal Natural Product Transfer" and discusses its relevance for our understanding of allelopathic interactions. The knowledge that specialized metabolites might in general be readily translocated from one plant into others should significantly contribute to our understanding of plant-plant interactions and-in particular-to the evolution of typical allelopathic effects, such as inhibition of growth and germination of potential competitors.

Vigorous Growing of Donor Plantlets by Liquid Overlay in Subcultures Is the Key to Cryopreservation of Endangered Species Pogostemon yatabeanus.

Cryopreservation is a unique option for the long-term conservation of threatened plant species with non-orthodox or limitedly available seeds. However, the wide application of cryopreservation for the protection of wild flora is hampered by some reasons: limits of source material available, difficulties in in vitro propagation, needs to re-optimize protocol steps for new species, etc. In this study, using an endemic and endangered Korean species, Pogostemon yatabeanus, we investigated subculture medium and supplements on in vitro growth of donor plants: medium strength, gelling agents, liquid overlay, plant hormones, and activated charcoal. Subculture conditions of each cycle tested significantly impacted on height and dry weight of subcultured donor plantlets. Among the treatments tested, the overlay of the liquid medium on top of gellan gum-gelled medium significantly increased the growth of shoots and roots. In the droplet-vitrification procedure, the survival and regeneration of cryopreserved shoot tips were critically impacted by the dry weight of donor plantlets (CORELL = 0.85~0.95) which was affected by the following subculture conditions. Moreover, every subsequent subculture cycle before cryopreservation positively or negatively impacted post-cryopreservation regeneration. This study highlights the vigor of donor plantlets for post-cryopreservation regeneration and provides practices for the revitalization of donor plants during subcultures.

Autotetraploidization Gives Rise to Differential Gene Expression in Response to Saline Stress in Rice.

Plant polyploidization represents an effective means for plants to perpetuate their adaptive advantage in the face of environmental variation. Numerous studies have identified differential responsiveness to environmental cues between polyploids and their related diploids, and polyploids might better adapt to changing environments. However, the mechanism that underlies polyploidization contribution during abiotic stress remains hitherto obscure and needs more comprehensive assessment. In this study, we profile morphological and physiological characteristics, and genome-wide gene expression between an autotetraploid rice and its diploid donor plant following saline stress. The results show that the autotetraploid rice is more tolerant to saline stress than its diploid precursor. The physiological characteristics were rapidly responsive to saline stress in the first 24 h, during which the elevations in sodium ion, superoxide dismutase, peroxidase, and 1-aminocyclopropane-1-carboxylic acid were all significantly higher in the autotetraploid than in the diploid rice. Meanwhile, the genome-wide gene expression analysis revealed that the genes related to ionic transport, peroxidase activity, and phytohormone metabolism were differentially expressed in a significant manner between the autotetraploid and the diploid rice in response to saline stress. These findings support the hypothesis that diverse mechanisms exist between the autotetraploid rice and its diploid donor plant in response to saline stress, providing vital information for improving our understanding on the enhanced performance of polyploid plants in response to salt stress.

Potential of In Vitro Culture of Scutellaria baicalensis in the Formation of Genetic Variation Confirmed by ScoT Markers.

The in vitro culture technique can be used for micropropagation of medicinal plants as well as for creating genotypes with an improved profile of phytochemical compounds. For this purpose, somaclonal variability may be used for the induction of genetic diversity among regenerants. The paper presents a protocol for obtaining Scutellaria baicalensis regenerants by indirect organogenesis and the assessment of their genetic variability with the use of start codon-targeted markers. The most intense process of indirect shoot organogenesis was observed on Murashige and Skoog medium supplemented with kinetin and 6-Benzylaminopurine (0.5 mg × dm-3 each)-7.4 shoot per explant on average. The callogenesis process occurred on the medium supplemented with TDZ, while the medium supplemented with GA3 allowed for direct shoot organogenesis and was used for the micropropagation of regenerants. In the analysis of plantlets obtained by indirect organogenesis, 11 ScoT markers generated a total of 130 amplicons, 45 of which were polymorphic. This analysis showed genetic diversity of regenerants in relation to the donor plant as well as within them, with mean similarity among the analyzed genotypes at the level of 0.90. This study confirms that the use of in vitro cultures allows for the possibility to generate genetic variability in Scutellaria baicalensis, which can be effectively revealed with the use of the SCoT marker.

Clonal Propagation of Walnuts (Juglans spp.): A Review on Evolution from Traditional Techniques to Application of Biotechnology.

Walnuts (Juglans sp.) are allogamous species. Seed-derived plants are not always superior to the selected parent. Clonal propagation of selected stock plants is an essential requirement for the clonal fidelity of the descendants and to maintain their genetic structure. Selection of the desired plant is realized only after reaching maturity, and characterizing and evaluating the performance of adult trees require a long time. Clonal propagation methods ensure proper transmission of characters to descendants and can be used effectively in breeding programs. The commercialization of a cultivar or rootstock depends on the success of vegetative propagation. Walnuts, like other tree species, are recalcitrant to conventional vegetative propagation methods and even non-conventional in vitro culture (micropropagation). Elucidation of factors determining the success of cloning of desired plants would contribute to understanding current limitations for most genotypes of Juglans. We outline the role of grafting and cuttings and stool layering, as well as in vitro culture on walnut multiplication. These techniques are, in practice, entirely different; nevertheless, they are affected by common factors. The incompatibility of stock-scion and the reduced ability of stem cuttings to root are the main bottlenecks for grafting and cutting, respectively. Genotype, age, and physiological status, reinvigoration or rejuvenation-treatment of donor plant, period of harvesting and processing of explants critically affect the results of methods followed. The in vitro culture technology is the most suitable for walnut cloning. This also has constraints that affect commercial propagation of most desired genotypes. We describe comprehensive results and synthesis in this review on the asexual reproduction of walnuts, providing a better comprehension of the limiting factors and the ways to overcome them, with direct implications on commercial propagation and the releasing of outstanding genotypes.

High‑frequency plant regeneration and genetic fidelity assessment of regenerants by molecular and biochemical markers in Woodland Sage (Salvia nemorosa L.)

Salvia nemorosa L. is a valuable medicinal and ornamental plant from Lamiaceae . A high-frequency protocol for in vitro regeneration from S. nemorosa leaf explants was developed based on our results. Various plant growth regulators were evaluated for their effects on direct and indirect organogenesis , callogenesis, shoot multiplication, and rooting of explants at different concentrations. The maximum percentage of direct shoot regeneration (97.5%) and the number of shoots per explant (8.6) were obtained on MS medium supplement with 8 µM TDZ plus 8 µM NAA . The result revealed that media amended by 16 µM 2, 4-D with 8 or 16 µM BA was the best treatment for callus induction. Media containing the combination of 8 µM TDZ plus 2 µM NAA provided the highest rate of shoot induction (84%) and the highest number of shoots (5.4) from calli. Regenerated shoots were multiplied efficiently with an average of 7.4 shoots and 32.4 leaves per explant on media containing 12 µM TDZ. In the present study, TDZ and BA treatments led to the highest proliferation rate; however, adenine sulfate was preferred for proliferation because it did not produce hyperhydric plants. The genetic fidelity of 19 plantlets (one donor plant, nine direct and nine indirect regenerants) was appraised by 10 ISSR markers. The molecular analysis revealed that direct organogenesis produced true-to-type plantlets and could be employed for clonal multiplication of Woodland Sage. Indirect regenerants showed polymorphic bands (12.5–33.33%), confirming the somaclonal variation occurrence during indirect organogenesis. Also, HPLC analysis of regenerants showed that two indirect regenerants accumulated higher rosmarinic acid content than mother plants, while three of them accumulated lower rosmarinic acid content. As part of this study, molecular and biochemical markers have been employed to investigate somaclonal variation in in vitro regeneration of the Salvia genus for the first time, which could be utilized to develop reliable methods for multiplying elite lines and achieving high-yield lines. • A high-frequency protocol for S. nemorosa in vitro regeneration was developed. • TDZ and NAA combination produced plantlets with high genetic and biochemical fidelity. • Adenine Sulphate prevents the Hyperhydricity in regenerated plantlets. • The indirect regeneration affected PAL activity, rosmarinic acid, and genetic content.

In Vitro Multiplication and Cryopreservation of Penthorum chinense Shoot Tips.

This study provides alternative approaches toward ex situ conservation by means of in vitro seed germination and the multiplication of Penthorum chinense Pursh using nodal explants. An overlay of a liquid medium on top of a gelled medium significantly increased the growth of shoots and roots, while the presence of activated charcoal or growth regulators (benzyl adenine and α-naphthaleneacetic acid) decreased the growth. Shoot tips of in vitro plantlets were cryopreserved using a droplet-vitrification method. The standard procedure included preculture with 10% sucrose for 31 h and with 17.5% sucrose for 17 h, osmoprotection with loading solution C4-35% (17.5% glycerol + 17.5% sucrose, w/v) for 20 min, cryoprotection with alternative plant vitrification solution (PVS) A3-70% (29.2% glycerol + 11.7% DMSO + 11.7% EG + 17.4% sucrose, w/v) at 0 °C for 30 min, cooling the samples in liquid nitrogen using aluminum foil strips and rewarming by plunging into pre-heated (40 °C) unloading solution (35% sucrose) for 40 min. A three-step regrowth procedure starting with ammonium-free medium followed by ammonium-containing medium with and without growth regulators was essential for the regeneration of cryopreserved shoot tips. The species was found to be very sensitive to the chemical cytotoxicity of permeating cryoprotectants during cryoprotection and to ammonium-induced oxidant stress during initial regrowth steps. Improvement of donor plant vigor by using apical sections and liquid overlay on top of the solid medium for propagation, improved shoot tip tolerance to osmotic stress and increased post-cryopreservation regeneration up to 64% were observed following PVS B5-85% (42.5% glycerol + 42.5% sucrose) treatment for 60 min. The systematic approach used in this study enables fast optimization of the in vitro growth and cryopreservation procedure for a new stress-sensitive wild plant species.

Clonal Fidelity and Genetic Diversity of Micropropagated Hancornia speciosa Gomes (Apocynaceae) as Evaluated by Molecular Markers

The plant tissue culture procedures for asexual multiplication of Hancornia speciosa represent an important process facilitating the preservation of selected genotypes of this threatened species and large-scale production of plantlets for population reinforcement or other utilization. However, there is no research regarding the somaclonal variation of this threatened species at molecular level. This study aimed to evaluate the role of the multiplication process in the genetic stability of H. speciosa plantlets and calluses using molecular markers. The tissue culture techniques for H. speciosa micropropagation used in this study did not influence the occurrence of somaclonal variation, which can be related to the genotypes of the donor plants and to the low concentrations of growth regulators used in tissue culture procedures adopted. The results observed here provide a reliable methodology for further studies involving micropropagation techniques with the goal of preserving selected or endangered genotypes of H. speciosa without genetic losses and producing seedlings of this species on a large scale. In addition, it was possible to verify that the donor plants used in this study showed a relatively low genetic variability.

Effect of potato spindle tuber viroid variants and infection stage on seed transmission through pollen.

Viroids are small, proteinless single-stranded circular RNAs. In plants, they can be transmitted via infected pollen and seeds. The effectiveness of viroid transmission through pollen depends on both the viroid and host species. It is, however, unclear whether viroid variant type or infection stage influences seed transmission through pollen. In the present study, we collected pollen from petunia infected with nine different variants of the potato spindle tuber viroid (PSTVd) at various stages after inoculation and used the material to pollinate healthy plants. Five and eight PSTVd variants were transmitted by pollen at 3 and 6 mpi respectively. All variants were pollen-transmissible at 9 mpi. The foregoing results indicated that seed transmission of PSTVd through pollen collected from infected donor plants may depend on the time elapsed since inoculation. For variant no. EU862231, however, the rate of seed transmission via pollen may depend on the pollen viroid titre. Nevertheless, there was no apparent correlation between the transmission rate and the pollen viroid titre in the U23058 or V01465 variant. Hence, the relationship between the viroid transmission rate and the pollen viroid titre may depend on the viroid variant type.

Allelopathy by the invasive garden lupine inhibits the germination of native herbs

Allelopathy is the stimulatory or inhibitory effect of one plant on another plant by release of phytochemicals. It can affect the competitive interactions between plants, but the strength of the effect may depend on the tissue of the donor plant and the phylogenetic relatedness of the interacting species. Here, we examined the allelopathic effects of the invasive garden lupine Lupinus polyphyllus Lindl. (Fabaceae) on six native herbs from three families (Asteraceae, Caryophyllaceae, Fabaceae). We exposed the test species to aqueous leachates prepared from root or shoot tissue of L. polyphyllus and measured germination rate and germination time. Both leachates inhibited germination in all species (13%–84%), but shoot leachate was more allelopathic than root leachate in case of Fabaceae and Caryophyllaceae. Plants from closely related Fabaceae were least affected by L. polyphyllus leachates in terms of germination rate, but leachates delayed their germination. These results demonstrate that the invasive L. polyphyllus can inhibit the germination of co-occurring native species and suggest that allelopathy likely contributes to its invasion success. Our results have implications for management of invasive L. polyphyllus populations, emphasising the importance of the removal of mown plant material to diminish inhibitory allelopathic effects on local plants.

In vitro propagation for conservation and genetic fidelity of the near threatened Dimocarpus longan plant

BackgroundDimocarpus longan is a tropical tree that produces edible fruit. It is a neglected plant species that is listed as near threatened. In spite of its economic value, the propagation of longan cultivar using conventional methods is extremely difficult. The goal of this research is to produce and conserve this plant through in vitro propagation. ResultsIn order to form new shoots, sterilized shoot tip explants were cultured on Murashige and Skoog (MS) medium supplemented with benzyl adenine (BA) or 2-isobentenyl-adenine (2ip). For direct organogenesis, young leaves of new shoots were cultured on MS medium fortified with various concentrations of Thidiazuron (TDZ) or 6-(4-Hydroxy-3-methylbut-2-enylamino purine) (Zeatin). Gibbrellic acid (GA3) at different levels alone or in combination was used for shoot elongation. Also, indole-3-butyric acid (IBA) and naphthalene acetic acid (NAA) were used for root formation. MS medium supplemented with 1.00 mg/l 2ip was suitable for inducing axillary shoots from shoot tips (4.0 axillary shoots/explant). The highest significant 76% and numbers of adventitious buds from leaf base were achieved on MS medium containing 1.0 mg/l TDZ. These buds developed into the longest plantlets on GA3 at 3.0 mg/l and rooted well in ½MS containing 1.50 mg/l IBA plus 0.50 mg/l (NAA). About 70% in vitro plants were successfully acclimatized. The AFLP profile illustrated the genetic stability of gene expression action. The amplified fragment length polymorphisms (AFLPs) profile illustrated the progenies were extremely similar to the mother plants. According to our findings, MS medium containing 25 ppm salicylic acid (SA) and 5 ppm methyl jasmonate (MeJA) produced the highest percentage of apigenin in longan calli (77.09 and 2.637%, w/w). ConclusionA successful and efficient micropropagation protocol has been developed and described here for the first time, and it will be very useful for the clonal propagation and conservation of the near-threatened Dimocarpus longan plant. Micropropagated plants are genetically identical to the donor plant using the AFLP technique. The usefulness of salicylic acid and methyl jasmonate as elicitors for increasing in vitro production of secondary metabolites in plants is demonstrated in this work.

Triticale doubled haploid plant regeneration factors linked by structural equation modeling

Triticale regeneration via anther culture faces many difficulties, e.g., a low percentage of regenerated plants and the presence of albinos. Plant regeneration may be affected by abiotic stresses and by ingredients added to the induction medium. The latter influences biochemical pathways and plant regeneration efficiency. Among such ingredients, copper and silver ions acting as cofactors for enzymatic reactions are of interest. However, their role in plant tissue cultures and relationships with biochemical pathways has not been studied yet.The study evaluated relationships between DNA methylation, changes in DNA sequence variation, and green plant regeneration efficiency influenced by copper and silver ions during triticale plant regeneration. For this purpose, a biological model based on donor plants and their regenerants, a methylation-sensitive amplified fragment length polymorphism, and structural equation modeling were employed.The green plant regeneration efficiency varied from 0.71 to 6.06 green plants per 100 plated anthers. The values for the components of tissue culture-induced variation related to cytosine methylation in a CHH sequence context (where H is A, C, or T) were 8.65% for sequence variation, 0.76% for DNA demethylation, and 0.58% for de novo methylation. The proposed model states that copper ions affect the regeneration efficiency through cytosine methylation and may induce mutations through, e.g., oxidative processes, which may interfere with the green plant regeneration efficiency. The linear regression confirms that the plant regeneration efficiency rises with increasing copper ion concentration in the absence of Ag ions in the induction medium. The least absolute shrinkage and selection operator regression shows that de novo methylation, demethylation, and copper ions may be involved in the green plant regeneration efficiency. According to structural equation modeling, copper ions play a central role in the model determining the regeneration efficiency.