scholarly journals Mating System in a Native Norway Spruce (Picea abies [L.] KARST.) Stand-Relatedness and Effective Pollen Population Size Show an Association with the Germination Percentage of Single Tree Progenies

Diversity ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 266
Author(s):  
Oliver Caré ◽  
Oliver Gailing ◽  
Markus Müller ◽  
Konstantin V. Krutovsky ◽  
Ludger Leinemann

Norway spruce differs little in neutral genetic markers among populations and provenances often reported, but in terms of putative adaptive traits and their candidate genes, some clear differences have been observed. This has previously been shown for crown morphotypes. Stands with mostly narrow crown shapes are adapted to high elevation conditions, but these stands are scattered, and the forest area is often occupied by planted stands with predominantly broad crowned morphotypes. This raises questions on whether this differentiation can remain despite gene flow, and on the level of gene flow between natural and planted stands growing in close neighbourhood. The locally adapted stands are a valuable seed source, the progeny of which is expected to have high genetic quality and germination ability. The presented case study is useful for spruce plantation by demonstrating evaluation of these expectations. Immigrant pollen and seeds from planted trees could be maladaptive and may alter the genetic composition of the progeny. This motivated us to study single tree progenies in a locally adapted stand with narrow crowned trees in a partial mast year at nuclear genomic simple sequence repeat (SSR) markers. Spruce is a typical open-pollinated conifer tree species with very low selfing rates, which were also observed in our study (s = 0.3–2.1%) and could be explained by efficient cross-pollination and postzygotic early embryo abortion, common in conifers. The estimated high amount of immigrant pollen found in the pooled seed lot (70.2–91.5%) is likely to influence the genetic composition of the seedlings. Notably, for individual mother trees located in the centre of the stand, up to 50% of the pollen was characterised as local. Seeds from these trees are therefore considered to retain most of the adaptive variance of the stand. Germination percentage varied greatly between half-sib families (3.6–61.9%) and was negatively correlated with relatedness and positively with effective pollen population size of the respective families. As pollen mostly originated from outside the stand and no family structures in the stand itself were found, germination differences can likely be explained by diversity differences in the individual pollen cloud.

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Juan Zhao ◽  
Hui Li ◽  
Guangxin Chen ◽  
Lijun Du ◽  
Peiyan Xu ◽  
...  

Abstract Background Aneuploidy is the most frequent cause of early-embryo abortion. Any defect in chromosome segregation would fail to satisfy the spindle assembly checkpoint (SAC) during mitosis, halting metaphase and causing aneuploidy. The mitotic checkpoint complex (MCC), comprising MAD1, MAD2, Cdc20, BUBR1 and BUB3, plays a vital role in SAC activation. Studies have confirmed that overexpression of MAD2 and BUBR1 can facilitate correct chromosome segregation and embryo stability. Research also proves that miR-125b negatively regulates MAD1 expression by binding to its 3′UTR. However, miR-125b, Mad1 and Bub3 gene expression in aneuploid embryos of spontaneous abortion has not been reported to date. Methods In this study, embryonic villi from miscarried pregnancies were collected and divided into two groups (aneuploidy and euploidy) based on High-throughput ligation-dependent probe amplification (HLPA) and Fluorescence in situ hybridization (FISH) analyses. RNA levels of miR-125b, MAD1 and BUB3 were detected by Quantitative real-time PCR (qRT-PCR); protein levels of MAD1 and BUB3 were analysed by Western blotting. Results statistical analysis (p < 0.05) showed that miR-125b and BUB3 were significantly down-regulated in the aneuploidy group compared to the control group and that MAD1 was significantly up-regulated. Additionally, the MAD1 protein level was significantly higher in aneuploidy abortion villus, but BUB3 protein was only mildly increased. Correlation analysis revealed that expression of MAD1 correlated negatively with miR-125b. Conclusion These results suggest that aneuploid abortion correlates positively with MAD1 overexpression, which might be caused by insufficient levels of miR-125b. Taken together, our findings first confirmed the negative regulatory mode between MAD1 and miR-125b, providing a basis for further mechanism researches in aneuploid abortion.


Author(s):  
Neelam Bhardwaj ◽  
Tanuja Kapoor ◽  
Parveen Sharma

Background: Ricebean [Vigna umbellata (Thunb.) Ohwi and Ohashi] is a multipurpose grain legume of Mid-Himalayan region mainly cultivated for food, fodder, green manure and has emerged as a good alternative to other pulse crops such as blackgram and greengram which do not flourish in this region due to their susceptibility to cold temperature stress. It is well reported that the nutritional value of ricebean is higher as compared to many other legumes of the Vigna family and has some superior qualities greater than greengram, blackgram and cowpea. It is also resistance to drought, diseases and pests specially the storage pests during growth period and possesses high percentage of seed viability. Despite having all the favourable traits, it is not much popular among the farmers due to the late maturity and indeterminate growth habit. Instead, farmers prefer other crops which fit easily into their cropping pattern and are easy to harvest. A little genetic improvement with respect to maturity and growth habit can revive its cultivation and show great results in its production as a valuable crop. Thus, the present investigation was formulated to introgress desired traits from mash and adzukibean into otherwise high yielding ricebean genotypes using inter-specific hybridization. Methods: The present investigation involves the inter-specific hybridization among three Vigna species viz, ricebean (Vigna umbellata), blackgram (Vigna mungo) and adzukibean (Vigna angularis). In the year 2017, six genotypes of ricebean (RBHP-36, RBHP-38, RBHP-43, RBHP-61, RBHP-107 and RBHP-108) were crossed with two genotypes of blackgram (HimMash-1 and Palampur-93) and one genotype of adzukibean (HPU-51) in glasshouse conditions. Result: The study revealed that successful crosses were possible only between ricebean and blackgram. All the Inter-specific crosses showed very low pod set percentage ranging from 0 -4% and F1 germination percentage ranging from 20-42%. Pod set percentage and pods harvested varied with combinations of two parental cultivars of each species for most of the inter-specific hybrids. The successful pod set was observed in 16 out of 36 inter-specific crosses. Highest crossability was observed in blackgram and ricebean crosses. Crossing of adzukibean with ricebean showed poor or no pod set among the entire cross combinations which are attributed to early embryo abortion and degeneration during embryogenesis.


2019 ◽  
Vol 70 (21) ◽  
pp. 6229-6244
Author(s):  
Gang Li ◽  
Wenxuan Zou ◽  
Liufang Jian ◽  
Jie Qian ◽  
Jie Zhao

Abstract Embryogenesis is an essential process during seed development in higher plants. It has previously been shown that mutation of the Arabidopsis non-SMC element genes AtNSE1 or AtNSE3 leads to early embryo abortion, and their proteins can interact with each other directly. However, the crucial regions of these proteins in this interaction and how the proteins are cytologically involved in Arabidopsis embryo development are unknown. In this study, we found that the C-terminal including the Ring-like motif of AtNSE1 can interact with the N-terminal of AtNSE3, and only the Ring-like motif is essential for binding with three α motifs of AtNSE2 (homologous to AtMMS21). Using genetic assays and by analysing molecular markers of cell fate decisions (STM, WOX5, and WOX8) in mutant nse1 and nse3 embryos, we found that AtNSE1 and AtNSE3 work non-redundantly in early embryo development, and that differentiation of the apical meristem and the hypophysis fails in the mutants, which have disrupted auxin transportation and responses. However, the upper cells of the suspensor in the mutants seem to have proper embryo cell identity. Cytological examination showed that cell death occurred from the early embryo stage, and that vacuolar programmed cell death and necrosis in the nse1 and nse3 mutant embryos led to ovule abortion. Thus, AtNSE1 and AtNSE3 are essential for maintaining cell viability and growth during early embryogenesis. Our results improve our understanding of the functions of SMC5/6 complex in early embryogenesis in Arabidopsis.


2004 ◽  
Vol 197 (1-3) ◽  
pp. 39-48 ◽  
Author(s):  
J Burczyk ◽  
A Lewandowski ◽  
W Chalupka

2002 ◽  
Vol 50 (1) ◽  
pp. 93 ◽  
Author(s):  
Alison Shapcott

Triunia robusta, which until recently was thought to be extinct, is now classified nationally as endangered. It is an understorey species restricted to the subcoastal rainforests in a small region of the Sunshine Coast, Queensland. The project involved sampling the genetic variation and measuring the population size and size distribution of T. robusta and its geographically closest congener T. youngiana, which occurs further south and has a wider geographic distribution. A total of 877 T. robusta plants were recorded across the 11 populations, approximately half (56.8&percnt;) of these were juveniles less than 1 m tall, whereas in T. youngiana only about 36.4&percnt; of a population was composed of juveniles. Genetic diversity was similar but significantly higher for T. robusta than T. youngiana if the very small T. robusta populations (2 or 3 plants) were excluded from analysis (P &lt; 0.05). The mean percentage of polymorphic loci among populations was high for both species. Triunia robusta is not, on average, more inbred than the more common T. youngiana. There was more differentiation between the T. robusta populations, which were in close proximity, than between the more geographically separated T. youngiana populations. Thus, there is evidence of more gene flow between populations of T. youngiana than between those of T. robusta. However, there was no geographic relationship between genetic similarity and geographic proximity in T. robusta


Behaviour ◽  
2015 ◽  
Vol 152 (14) ◽  
pp. 1933-1951 ◽  
Author(s):  
Tamsin Burbidge ◽  
Thari Parson ◽  
Paula C. Caycedo-Rosales ◽  
Carlos Daniel Cadena ◽  
Hans Slabbekoorn

Behavioural barriers to gene flow can play a key role in speciation and hybridisation. Birdsong is well-known for its potential contribution to such behavioural barriers as it may affect gene flow through an effect on territorial and mating success across population boundaries. Conspecific recognition and heterospecific discrimination of acoustic variation can prevent or limit hybridization in areas where closely related species meet. Here we tested the impact of song differences on territorial response levels between two adjacent Henicorhina wood-wren species along an elevational gradient in Colombia. In an earlier study, playback results had revealed an asymmetric response pattern, with low-elevation H. leucophrys bangsi responding strongly to any conspecific or heterospecific song variant, whereas high-elevation H. anachoreta birds discriminated, responding more strongly to their own songs than to those of bangsi. However, in that study we could not exclude a role for relative familiarity to the song stimuli. In the current study we confirm the asymmetric response pattern with song stimuli recorded close to and on both sides of the distinct acoustic boundary. Furthermore, we also show a previously unnoticed divergence in singing style between these two wood-wren species, which may contribute to an acoustically guided barrier to hybridization in this secondary contact zone.


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