Efficient plant regeneration via meristematic nodule culture in Paeonia ostii ‘Feng Dan’

Tree peony (Paeonia sect. Moutan) is an economically important multipurpose woody plant in terms of its medical, ornamental and oil values, but its breeding and industrial development are severely limited due to inefficient traditional propagation methods and existing in vitro regeneration systems. Meristematic nodules (MNs) are an attractive alternative to solve this problem. This study first presented a protocol for in vitro regeneration of P. ostii ‘Feng Dan’ via MN culture with four consecutive steps, including embryogenic callus (EC) formation, MN induction and leaf cluster differentiation, shoot elongation, rooting and acclimatization. The highest EC induction rate (81.25%) was achieved when cotyledons were cultured on modified Murashige and Skoog (mMS) medium with 4.04 µM N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) + 5.37 µM α-naphthylacetic acid (NAA) for 30 days. The optimal MN induction rate (100%) and leaf cluster differentiation rate (45.83%) were obtained when ECs were cultured on modified woody plant medium (mWPM) supplemented with 2.02 µM CPPU + 2.27 µM thidiazuron (TDZ) for a subculture time of 10 days. The combination of 1.29 µM 6-benzyladenine (BA) + 0.58 µM gibberellin (GA3) yielded the best shoot elongation (13.40 shoots per nodule), rooting rate (43.33%) and consequently survival rate (45.83%). The study will be beneficial to the mass propagation, breeding and genetic improvement of tree peony.

Somatic Embryogenesis In Rosa Chinensis CV. ‘Parson’s Pink China’

This study investigated the effects of explant type, plant growth regulator concentration, callis status, medium conversion time, and medium tilt on the growth of rose somatic embryos. The results showed that Rosa chinensis cv. ‘Parson’s Pink China’ leaves could induce normal embryogenic calli but petioles could not. When the 2,4-dichlorophenoxyacetic acid concentration was 3.0 mg/L, the callis induction rate was the highest in the embryo proliferation medium (EP medium) supplemented with 0.5mg/L kinetin, and white and reddish-brown translucent calli were the main type of embryogenic calli induced. As the culture time in EP medium was extended, the relative induction rate for secondary embryos and multicotyledon secondary embryos gradually increased when transferred to embryo maturation medium (EM medium), but the induction rate for somatic embryos decreased. Placing the EM medium at an angle of 45° made the somatic embryos germinate faster and the germination rate was also higher. The germination buds produced by the somatic embryos with two cotyledons showed the fastest germination and greatest survival rates. The results of this experiment will help improve somatic embryo regeneration rates and explore new ways of regeneration, and lays the foundation for further optimization of the somatic embryo genetic transformation system.

Selection Gain of Maize Haploid Inducers for the Tropical Savanna Environments

Lacking elite haploid inducers performing high haploid induction rate (HIR) and agronomic performance is one of fundamental factors hindering the rapid adoption of doubled haploid technology in maize hybrid breeding, especially under tropical savanna climate. Breeding haploid inducers for specific agro-ecology, thus, is indispensable yet challenging. We used temperate inducer Stock6 as genetic source for haploid induction ability and eight tropical maize genotypes as principal donors for agronomic adaptation. Three cycles of modified ear-to-row with 5% intra-family selection were applied in a population set of 78 putative haploid inducer families emphasized on agronomic performance, R1-nj anthocyanin intensity, and inducer seed set. Genetic gains, variance components, and heritability on given traits were estimated. Hierarchical clustering based on five selection criteria was performed to investigate the phenotypic diversity of putative families. Cycle effect was predominant for all observed traits. Realized genetic gain was positive for HIR (0.40% per cycle) and inducer seed set (30.10% or 47.30 seeds per ear per cycle). In this study, we reported the first haploid inducers for regions under tropical savanna climate. Three inducer families, KHI-42, KHI-54, and KHI-64, were promising as they possessed HIR about 7.8% or 14 haploid seeds per tester ear and inducer seed rate about 95.0% or 208 inducer seeds per ear. The breeding method was effective for enhancing the seed set and the expression of R1-nj anthocyanin marker of inducers, yet it showed a low effectiveness to improve haploid induction rate. Introgression of temperate inducer Stock6 into tropical gene pool followed by phenotypic selections through modified ear-to-row selection on inducer seed set and R1-nj marker did not compromise the agronomic traits of tropical inducer families. Implications and further strategies for optimizing genetic gain on HIR are discussed.

Efficient Plant Regeneration System for New Guinea Impatiens (Impatiens Hawkeri W. Bull) CV. ‘Violet’and ‘Scarlet Bronze Leaf’

New Guinea Impatiens (Impatiens hawkeri W. Bull) is an eye-popping landscaping plant which is of bright and colorful blooms. A highly efficient in vitro plant regeneration system through direct shoot organogenesis was established for the first time from hypocotyl with partial cotyledons of New Guinea Impatiens. The results showed that Explant sterilization method, basic medium type,AgNO3,sucrose and plant growth regulators (PGRs) have greatly influences on in vitro morphogenesis.The regeneration rate in regeneration media that MS supplemented with 0.5mg·L−1 TDZ and 0.1mg·L−1 NAA was acceptable ,the induction rate of 'Violet' was 86.67%, and its proliferation coefficient was 5.27, while the induction rate of 'Scarlet Bronze Leaf' was 83.33%, and its proliferation coefficient was 5.13.PIC was unable to induce clumped sprouts, but it had a better effect on callus induction.We also included a shoot multiplication stage using regeneration New Guinea Impatiens medium that MS supplemented with 0.8mg·L−1 6-BA,0.5mg·L−1 TDZ and 0.05mg ·L−1 NAA.Reducing sucrose concentration to 20g·L−1 or adding 1mg·L−1AgNO3 could alleviate the vitrification phenomenon in the process of tufted bud proliferation.The optimal root culture medium for the regenerated seedlings of 'violet' and 'scarlet bronze leaf' of New Guinea Impatiens was MS supplemented with 0.05mg·L−1IBA, the rooting rate reached 100%.The study examined the micropropagation responses of New Guinea Impatiens in the presence of various growth regulators and provided a simple and more suitable protocol adapted for the mass propagation of clones.

Seasonal regulation of singing-driven gene expression associated with song plasticity in the canary, an open-ended vocal learner

Songbirds are one of the few animal taxa that possess vocal learning abilities. Different species of songbirds exhibit species-specific learning programs during song acquisition. Songbirds with open-ended vocal learning capacity, such as the canary, modify their songs during adulthood. Nevertheless, the neural molecular mechanisms underlying open-ended vocal learning are not fully understood. We investigated the singing-driven expression of neural activity-dependent genes (Arc, Egr1, c-fos, Nr4a1, Sik1, Dusp6, and Gadd45β) in the canary to examine a potential relationship between the gene expression level and the degree of seasonal vocal plasticity at different ages. The expression of these genes was differently regulated throughout the critical period of vocal learning in the zebra finch, a closed-ended song learner. In the canary, the neural activity-dependent genes were induced by singing in the song nuclei throughout the year. However, in the vocal motor nucleus, the robust nucleus of the arcopallium (RA), all genes were regulated with a higher induction rate by singing in the fall than in the spring. The singing-driven expression of these genes showed a similar induction rate in the fall between the first year juvenile and the second year adult canaries, suggesting a seasonal, not age-dependent, regulation of the neural activity-dependent genes. By measuring seasonal vocal plasticity and singing-driven gene expression, we found that in RA, the induction intensity of the neural activity-dependent genes was correlated with the state of vocal plasticity. These results demonstrate a correlation between vocal plasticity and the singing-driven expression of neural activity-dependent genes in RA through song development, regardless of whether a songbird species possesses an open- or closed-ended vocal learning capacity.

Dormant phages communicate to control exit from lysogeny

Temperate bacterial viruses (phages) can transition between lysis - replicating and killing the host, and lysogeny - existing as dormant prophages while keeping the host viable. It was recently shown that upon invading a naïve cell, some phages communicate using a peptide signal, termed arbitrium, to control the decision of entering lysogeny. Whether communication can also serve to regulate exit from lysogeny (known as phage induction) remains unclear. Here we show that arbitrium-coding prophages continue to communicate from the lysogenic state by secreting and sensing the arbitrium signal. Signaling represses DNA-damage dependent phage induction, enabling prophages to reduce induction rate when surrounded by other lysogens. We show that the mechanism by which DNA damage and communication are integrated differs between distantly related arbitrium-coding phages. Additionally, signaling by prophages tilts the decision of nearby infecting phages towards lysogeny. Altogether, we find that phages use small molecule communication throughout their entire life-cycle to measure the abundance of lysogens in the population, thus avoiding wasteful attempts at secondary infections when they are unlikely to succeed.

Effectiveness of first trimester ultrasound screening in reduction of postdated labor induction rate

Background: The gestational age calculation by ultrasonography (USG) at first trimester is based on crown-rump length is more accurate, less erratic than last menstrual period based dating. Utilization of first trimester based scanning in dating the pregnancy will reduce the labor induction rate and consequently reduce the morbidity related to induction of labor.Methods: A comparative cross-sectional study was done among 314 booked antenatal women visiting department of obstetrics and gynecology, BPKIHS for regular check-up between 37 and 41 weeks of gestation. Expected date of delivery was calculated from crown rump length (CRL) of the first trimester scan for USG group while last menstrual period was taken to calculate expected date of delivery for LMP group and were called for induction at 41 weeks of gestation. The rates of labor induction, emergency cesarean section (CS) among induced group, indication of CS and mode of delivery were compared in both the groups.Results: There was 14% labor induction rate in USG group and 24.2% in LMP (last menstrual period) group and differed significantly (p=0.022). There was no difference in the mode of delivery among participants in either groups. The rate of emergency CS among women undergoing induction of labor was 54.5% and 39.5% respectively for USG and LMP groups (p=0.258). Overall, non-reassuring fetal heart rate was the most common indication for CS in both the groups.Conclusions: The finding suggests first trimester scan among all pregnancies will reduce the post-dated inductions, as well as need of CS.

Silver nanoparticles enhanced efficiency of explant surface disinfection and somatic embryogenesis in Begonia tuberous via thin cell layer culture

In vitro culture establishment is one of the most important stages in micropropagation. The disinfectant effectiveness depends on the type of surface disinfectant, concentration and the time treatment. In this initial study, silver nanoparticles (AgNPs) were used as a disinfectant for petioles, flower stalks and stems of Begonia tuberous. In addition, thin cell layer culture (TCL) technique has been applied for the purpose of somatic embryogenesis. The results showed that AgNPs were effective in eliminating infectious microorganisms on B. tuberous explants; which were identified included 4 species of fungi (Fusarium sp., Aspergillus aculeatus, Trichoderma sp. and Penicillium sp.) and 1 species of bacteria (Pseudomonas sp.). At concentrations of 200 ppm and 300 ppm, AgNPs were not only effective in disinfection but also increased the induction rate of somatic embryogenesis in flower stalk TCL explants (approximately 40.00%); a similar effect was observed in stem TCL explants at the same concentration. Meanwhile, for petiole TCL explants, the induction rate of somatic embryogenesis was optimal when using AgNPs at a concentration of 100 - 300 ppm to disinfected the explant. In contrast, at high (400 ppm) or low (50 ppm) concentrations of AgNPs did not play a disinfecting role and stimulated somatic embryogenesis. In addition, explants derived from AgNPs sterilization did not show any abnormalities in somatic embryogenesis with shapes such as globular, heart, torpedo, and cotyledon. AgNPs showed double efficacy in sterilization of explants and improved efficiency of somatic embryogenesis from TCL petioles, flower stalks and stems explants; thus increasing the efficiency micropropagation of B. tuberous.

PL-4 (CIP596131.4): an Improved Potato Haploid Inducer

Dihaploid production from elite tetraploid cultivars is key to both traditional and novel breeding approaches that seek to simplify potato genetics. For this purpose, efficient and widely compatible haploid inducers (HIs) are needed. We compared PL-4, a new HI developed at the International Potato Center, to known HIs IvP101 and IvP35. By pollination of elite tetraploid breeding lines, we showed that PL-4 performed significantly better and had a homogeneous response regardless of the genetic background of the pistillate parents, on the most important efficiency traits—number of dihaploids per 100 fruits and haploid induction rate. Moreover, PL-4 exhibited a reduced proportion of hybrid seeds, a convenient trait for efficient screening. In this context, we recommend PL-4 as an enhanced HI for the potato breeding community.

Comparative Data about Estrus Induction and Pregnancy Rate on Lacaune Ewes in Non-breeding Season after Melatonin Implants and Intravaginal Progestagen

Backgroung: Seasonal anestrus in ewes reduces reproductive efficiency and hinders productivity. Exogenous hormones can be used to facilitate the induction and synchronization of estrus in the anestrus period. The aim of this study was to evaluate the pregnancy rate in ewes after the treatment with different hormones and fixed time artificial insemination. Methods: The ewes were randomly divided in 4 (n=4) groups: Melatonin group (Group 1), Melatonin and Medroxyprogesterone group (Group 2), Medroxyprogesterone group (Group 3) and control group (Group 4). Pregnancy rate, estrus induction rate and litter size were determined and compared. Result: The estrus induction rate in our study was 100% for the first 3 groups and 6.25% for the 4th group. The pregnancy rate was between 4.16% (group 4) and 95.83% (group 2). For the others groups the values were 89.58% for the first group and 91.67%, for the 3rd group. The prolificacy rate was between 1 (control group) and 1.71 (2nd group), with intermediate values for the other 2 groups: 1.21 for 1st group and 1.27 for the 3rd group.