Twin Seedlings Research Articles

Polyembryony in Santalum album – a double-edged sword for plant regeneration

ABSTRACT Santalum album is a hemiparasitic evergreen tree known for its heartwood oil, widely used in the cosmetics and aromatherapy industry. Overexploitation in the past few decades has led to the classification of this species as Vulnerable on the IUCN Red List of Threatened Species. Drupes of S. album are single-seeded and usually monoembryonic in nature, producing normal seedlings. However, in a previous study, we also observed some polyembryonic seeds. In this news article we share our polyembryony findings from Marayoor population as well as the growth and survival of seedlings which emerged from polyembryonic seeds. We found that less than 1% of the seeds in Marayoor population exhibited polyembryony (duplets). The general trend was that one radicle emerged 2-3 days earlier than the other and grew faster and healthier compared to the radicle from monoembryonic seeds. The second (smaller) seedling from polyembryonic seeds began to degenerate if not separated, but it survived well (albeit with low growth potential) once transplanted into a separate polybag. In S. album, polyembryony does not seems to be an essential ecological competitive strategy, unlike in several invasive species. For mass-scale seedling production of this vulnerable species, we recommend separating twin seedlings soon after their emergence for a better survival rate.

Polyembryonic twin seedlings in Madhuca diplostemon (Sapotaceae) - a critically endangered and endemic species of the Western Ghats

Madhuca diplostemon is a critically endangered and endemic species of the southern Western Ghats, represented by a single mature individual. The occurrence of twin seedlings in this species is being reported here for the first time will be useful future genetic improvement and conservation programs for this species.

Cover Picture and Issue Information

Journal of EcologyVolume 111, Issue 3 p. 537-539 COVER PICTURE AND ISSUE INFORMATIONFree Access Cover Picture and Issue Information First published: 01 March 2023 https://doi.org/10.1111/1365-2745.13914AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Cover image: Twin seedlings of mistletoe, Viscum album, established on a branch of apple, Malus domestica, the parasite’s most frequent British host. These seedlings, three to four years old, are probably true twins, arising from a single polyembryonic seed. Photograph by Jonathan Briggs. For full details see pages 701–739. Volume111, Issue3March 2023Pages 537-539 RelatedInformation

Fine Mapping and Candidate-Gene Analysis of an open glume multi-pistil 3 (mp3) in Rice (Oryza sativa L.)

The rice mutant mp3 was derived from an indica–japonica cross between Rejing35 and XieqingzaoB, producing an inconstant number of pistils ranging from one to four pistils in a floret at heading stage, which also developed an open-glume with one or two seeds and twin seedlings at mature and seedling stage. Several altered characteristics, including filling grain panicle–1 (62.90), grain-setting rate (60.48%) and grain yield plant–1 (13.42 g), decreased but an increase in 1000-grain weight (36.87 g) was observed. Genetic analysis revealed that the mp3 mutant phenotype was controlled by a single recessive gene. Using a chromosome walking strategy in the F2 population of 02428/mp3, the mp3 gene was fine mapped between L3-135 and RM7576, with a physical distance of 30.617 kb on rice chromosome 3. Four candidate genes were found in this region referred to the rice genome annotations. LOC_Os03g11614/OsMADS1 corresponded with the mutant mp3 phenotype. Sequencing showed no sequence alterations in the coding and promoter sequence of the LOC_Os03g11614/OsMADS1 of mp3. The mp3 gene may be an allelic gene with three previously reported genes but controlled different mutant floral organ phenotypes in rice. Therefore, this mp3 gene provided a novel perspective on the biological function of OsMADS1 in the development of rice floral organ.

Effects of ploidy variation on promoter DNA methylation and gene expression in rice (Oryza sativa L.)

BackgroundPolyploidy, or whole-genome duplication (WGD) promotes genetic diversification in plants. However, whether WGD is accompanied by epigenetic regulation especially DNA methylation remains yet elusive. Methylation of different region in genomic DNA play discrete role in gene regulation and developmental processes in plants.ResultsIn our study, we used an apomictic rice line (SARII-628) that produces twin seedlings of different ploidy for methylated DNA immunoprecipitation sequencing (MeDIP-seq). We compared the level of methylation and mRNA expression in three different (CG, CHG, and CHH) sequence contexts of promoter region among haploid (1X), diploid (2X), and triploid (3X) seedling. We used MeDIP-Seq analysis of 14 genes to investigate whole genome DNA methylation and found that relative level of DNA methylation across different ploidy was in following order e.g. diploid > triploid > haploid. GO functional classification of differentially methylated genes into 9 comparisons group of promoter, intergenic and intragenic region discovered, these genes were mostly enriched for cellular component, molecular function, and biological process. By the comparison of methylome data, digital gene expression (DGE), mRNA expression profile, and Q-PCR findings LOC_ Os07g31450 and LOC_ Os01g59320 were analyzed for BS-Seq (Bisulphite sequencing).ConclusionsWe found that (1) The level of the promoter DNA methylation is negatively correlated with gene expression within each ploidy level. (2) Among all ploidy levels, CG sequence context had highest methylation frequency, and demonstrated that the high CG methylation did reduce gene expression change suggesting that DNA methylation exert repressive function and ensure genome stability during WGD. (3) Alteration in ploidy (from diploid to haploid, or diploid to triploid) reveals supreme changes in methylation frequency of CHH sequence context. Our finding will contribute an understanding towards lower stability of CHH sequence context and educate the effect of promoter region methylation during change in ploidy state in rice.

Managing of Organic-Biofertilizers Nutrient Based and Water Saving Technology for Restoringthe Soil Health and Enhancing the Sustainability of Rice Production in Indonesia

The effort to secure the sustainability of rice productivity is one of the main priority in providing enough food for rapidly growing population in Indonesia. Meanwhile, intensive use of agrochemicals fertilizers since the adoption of green revolution not only has boosted food production significantly but also accelerated to the soil health degradation. The intensive research has been done to develop of biofertilizers as consortia of inoculants (Azotobacter sp., Azospirillum sp., Pseudomonas sp., Bacillus sp., and Acinetobacter sp). The formulated bioterilizers combined with water saving technology were implemented’ as an integrated organic-biofertilizers based of nutrients management and ‘water saving technology, known as “IPATBO“. Two young single rice seedling were planted at 30x35 cm, fertilized with 2-5 ton ha−1 of organic ameliorant, and’ 500-1000 g of biofertlizers inoculant. The summarized field results from 2007-2018 at different locations in revealed that (1) the efficiency of water irrigation uses was increased by 35 %, (2) twin seedling planting technique of IPATBO increased the rice grain yield by 20-30 % compare to conventional methods, (3) application of 2–5 tons ha−1 of organic ameliorant reduced the application inorganic fertilizers by 25-50 %, improved the soils health and increased the rice productivity significantly. The obtained rice grain yield ranged from 6-11 t ha−1 was increased by 50-200 %. Briefly, IPATBO has a great prospect to increase the productivity from 5-6 to 6-8 tons ha−1 of rice grain yield and to improve the sustainability of food security in Indonesia.

Arabidopsis ICK/KRP cyclin-dependent kinase inhibitors function to ensure the formation of one megaspore mother cell and one functional megaspore per ovule.

In most plants, the female germline starts with the differentiation of one megaspore mother cell (MMC) in each ovule that produces four megaspores through meiosis, one of which survives to become the functional megaspore (FM). The FM further develops into an embryo sac. Little is known regarding the control of MMC formation to one per ovule and the selective survival of the FM. The ICK/KRPs (interactor/inhibitor of cyclin-dependent kinase (CDK)/Kip-related proteins) are plant CDK inhibitors and cell cycle regulators. Here we report that in the ovules of Arabidopsis mutant with all seven ICK/KRP genes inactivated, supernumerary MMCs, FMs and embryo sacs were formed and the two embryo sacs could be fertilized to form two embryos with separate endosperm compartments. Twin seedlings were observed in about 2% seeds. Further, in the mutant ovules the number and position of surviving megaspores from one MMC were variable, indicating that the positional signal for determining the survival of megaspore was affected. Strikingly, ICK4 fusion protein with yellow fluorescence protein was strongly present in the degenerative megaspores but absent in the FM, suggesting an important role of ICKs in the degeneration of non-functional megaspores. The absence of or much weaker phenotypes in lower orders of mutants and complementation of the septuple mutant by ICK4 or ICK7 indicate that multiple ICK/KRPs function redundantly in restricting the formation of more than one MMC and in the selective survival of FM, which are critical to ensure the development of one embryo sac and one embryo per ovule.

Penentuan Waktu Pemisahan Bibit Kembar Kelapa Sawit (Elaeis guineensis Jacq.) Asal Benih Multi Embrio di Pembibitan

The oil palm (Elaeis guineensis Jacq.) seed generally in form of germinated seed. Germinated seed purchased from oil palm seed producers often contained twin seedlings. The twin seedlings must be separated in pre-nursery before transplanted to the main-nursery. The aim of this research was to determine the best time of oil palm twin seedlings separation in nursery. The research was conducted on April to November 2016 in Politeknik Negeri Lampung. Single-factor experiment was arranged in randomized block design with three replications. The treatment was the age of twin seedling i.e.: 8 weeks after sowing (W1), 9 weeks after sowing (W2), 10 weeks after sowing (W3) and 11 weeks after sowing (W4). The data were analysed by general linear model analysis of variance (ANOVA). The means were separated using HSD at α=5% level. The result show the best time to separate the twin seedling in pre-nurserys is 9-11 weeks after sowing. Keywords: main-nursery, multi embryo, pre-nursery, twin seedlings

Morphological, cellular and molecular evidences of chromosome random elimination in vivo upon haploid induction in maize

The mechanism of maternal in vivo haploid induction is not fully understood. In this study, the young embryos were identified by morphology, cytology and simple sequence repeat (SSR) markers at different developmental stages in the cross HZ514 (sweet corn)×HZI1 (inducer). The results indicated that the low seed setting rate was determined by the inducer pollen during the process of fertilization. The mosaic endosperm kernels and the different percentages of aneuploidy, mixploidy, lagged chromosome, micronuclei, chromosomal bridge and ring chromosome were found in the cross; 7.37% of the haploid embryos carried chromosome segments from HZI1. About 1% twin seedlings resulted from the cross and were analyzed by cytology and SSR markers. Four pairs of twin seedlings had different chromosome numbers (2n=20 and 2n=10–20) and there were some chromosome fragments from HZI1. Aneuploidy, mixploidy and the abnormal chromosomes occurred in the in vivo haploid induction by HZI1, which is the cytological basis for haploid induction and indicates that the inducer's chromosomes are prone to be lost during mitotic and meiotic divisions. Morphological, cellular and molecular evidences reveal that complete or partial chromosome elimination from inducer HZI1 controls the maize in vivo haploid induction. DATAThe link refers to the raw data from: Morphological, cellular and molecular evidences of chromosome random elimination in vivo upon haploid induction in maize. Current Plant Biology. Raw data for phenotype, maker sequence and cytology could be directly downloaded by the link: http://dx.doi.org/10.5061/dryad.bt963

Occurrence of Polyembryony in Juniperus Polycarpos C. Koch.

The natural regeneration in Juniperus polycarpos is quite low due to seed dormancy. While studying the seed germination behaviour of Juniperus polycarpos, a twin seedling was found germinated from a single seed which has been reported. This is the first instance of occurrence of polyembryonic seedlings in Juniperus polycarpos which have been reported in this paper. The twin seedlings have been resulted due to the phenomenon of polyembryony which is of rare occurrence in this species, however, the production of twin seedlings has been reported earlier also in other forest tree species. The twin seedlings were found to be independent having separate taproots and cotyledons. The seedlings were later transplanted in a polybags filled with Soil: Sand: FYM (2:1:1 :) to observe the further growth of twin seedlings. After three months, it was noticed that both the twin seedlings shriveled and died where as normal seedlings continued to grow normally and produced all the essential features of a plant.

Occurrence of twin seedlings in Kingiodendron pinnatum (DC.) Harms (Leguminosae)- an endangered tree species of Western Ghats

Kingiodendron pinnatum (DC.) Harms (Leguminosae) is an Endangered and endemic tree species of Western Ghats. The recorded twin seedlings contributed to 20% of the abnormality among the germinated seedlings.

Development of multiple embryos in polyembryonic insertional mutant OsPE of rice

A T-DNA insertional mutant OsPE of rice gives twin and triplet seedlings in up to 20% of the seeds. Detailed cytological and histological analysis of OsPE indicated normal male and female gametogenesis in the OsPE mutant. Confocal laser scanning microscopic (CLSM) analysis of the developing seeds of OsPE showed multiple embryo development in up to 60% of the ovules. The multiple embryos, mostly twins and triplets, and rarely quadruplets, developed through sequential cleavage from a single zygotic embryo in each ovule. The reduced number of multiple seedlings compared with multiple embryos observed in CLSM study may be attributed to their inability to develop further due to competition in a single embryo sac. Key message Multiple seedlings in the OsPE mutant are due to sequential proliferation and cleavage of the zygotic embryos. The nucellar tissue was not involved in multiple embryo development.

A New report on twin seedlings in Semecarpus Kathalekanensis, a critically endangered tree species of the Myrisitca swamps of Western Ghats

In this paper, observation on twin seedlings in Semecarpus kathalekanensis is reported. Out of 850 seeds germinated (from seven individuals), two seeds gave out twin seedlings. Further, the growth of twin seedlings with normal seedlings have been recorded and discussed here.

Twin seedlings in Symplocos Kanarana Talb.

Symplocos kanarana Talbot (Family: Symplocaceae) is an evergreen tree species of the Western Ghats. During the nursery study, three twin seedlings of S. kanarana are recorded and it contributed 5% abnormality to the entire seedling lot.

Twin Seedlings Appeared in Mulberry Plants

Twin Seedlings Appeared in Mulberry Plants

A note on twin and triplet seedlings in Madhuca Latifolia Roxb.: An important bio-fuel yielding tree species

Madhuca latifolia is one of the economically important species, presently seeds of this species is used in biodiesel. In the present study we report twin and triplet seedlings in this species. Reporting of such variation in tree species is most important for future genetic improvement and conservation programmes.

A new approach for obtaining rapid uniformity in rice (Oryza sativa L.) via a 3x x 2x cross

A triploid (2n = 3x = 36) rice plant was obtained by screening a twin seedling population in which each seed germinated to two or three sprouts that were then crossed with diploid plants. One diploid plant was chosen among the various F1 progenies and developed into an F 2 population via self-pollination. Compared with the control variety Shanyou 63, this F 2 population had a stable agronomical performance in field trials, as confirmed by the F-test. The stability of the F 2 population was further substantiated by molecular analysis with simple sequence repeat markers. Specifically, of 160 markers assayed, 37 (covering all 12 chromosomes) were polymorphic between the parental lines. Testing the F 1 hybrid individually with these markers showed that each PCR product had only a single band instead of two bands from each parent. The bands were identical to either maternal (23 markers) or paternal (eight markers) bands or distinct from both parents (six markers). The amplified bands of all 60 randomly selected F 2 plants were uniform and identical to those of the F 1 hybrid. These results suggest that the F 1 plant is a non-segregating hybrid and that a stable F 2 population was obtained. This novel system provides an efficient means for shortening the cycle of hybrid rice seed production.

Twin seedlings in Melocanna baccifera (Roxb.), an important evergreen bamboo species of India

The paper describes the occurrence of the twin seedlings in Melocanna baccifera (Roxb.), an important evergreen bamboo species.

The polyembryo gene (OsPE) in rice

T-DNA insertional mutagenesis is one of the most important approaches for gene discovery and cloning. A fertile polyembryo mutant generated by T-DNA/Ds insertion in Oryza sativa, cv. Basmati 370 showed twin or triple seedlings at a frequency of 15-20%. T-DNA insertion was confirmed by 950 bp hpt gene amplification in the promoter region of the candidate gene. The annotated protein corresponding to the OsPE candidate gene has been reported as a hypothetical protein in O. sativa. OsPE gene lacked functional homologs in other species. No OsPE paralog was found in rice. No conserved domains were found in the protein coded by OsPE. RT-PCR showed the expression of OsPE gene in Basmati 370 shoots. Full-length OsPE gene was cloned in Basmati 370. The combined use of Southern blot, genome walking, TAIL-PCR, RT-PCR techniques, and bioinformatics led to the identification of a candidate gene controlling the multiple embryos in rice. There is gain of function, i.e., multiple embryos in the seeds in the knockout mutant OsPE whereas its wild-type allele strictly controls single embryo per seed. The seeds with multiple embryos are distributed at random in the rice mutant panicle. The origin of multiple embryos, whether apomictic, zygotic or both is under investigation.

Occurrence of conjointed twin seedlings in Fraxinus xanthoxyloides (Wall. Ex G.Don) DC.

The occurrence of conjointed twin seedlings in Fraxinus xanthoxyloides (Wall. ex G.Don) DC.- an important multipurpose tree species of cold desert has been reported. This is the first instance of occurrence of conjointed seedlings in Fraxinus xanthoxyloides which have been reported in this paper. The conjointed seedlings have been resulted due to the phenomenon of polyembryony, which is of rare occurrence in this species.