scholarly journals Potato Germplasm Enhancement Enters the Genomics Era

Agronomy ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 575 ◽  
Author(s):  
Paul C. Bethke ◽  
Dennis A. Halterman ◽  
Shelley H. Jansky

The goal of germplasm enhancement is to introgress traits from wild crop relatives into cultivated material and eventually cultivars. It seeks to restore genetic diversity that has been lost over time or to augment cultivated material with novel alleles that improve parents in breeding programs. This paper discusses potato germplasm enhancement efforts in the past, focusing on effective examples such as disease resistance and processing quality. In addition, it outlines new strategies for enhancement efforts, shifting the focus from evaluating phenotypes to tracking and manipulating specific DNA sequences. In the genomics era, germplasm enhancement will increasingly be focused on identifying and introgressing alleles rather than traits. Alleles will come from a broad pool of genetic resources that include wild species relatives of potato, landraces, cultivated potato itself, and distantly-related species. Genomics tools will greatly increase the efficiency of introgressing multi-genic traits and will make it possible to identify rare alleles and utilize recessive alleles.

2009 ◽  
Vol 57 (8) ◽  
pp. 688 ◽  
Author(s):  
F. M. Shapter ◽  
M. P. Dawes ◽  
L. S. Lee ◽  
R. J. Henry

The pericarp and aleurone layer of cereal grains are associated with the accumulation of anti-nutritional factors, vitamins, high-value proteins and trace elements. Variations in these tissues may be associated with important differences in the nutritional and functional value of cereals as human or animal feeds. Wild crop relatives (WCR) have been successfully utilised in breeding programs to improve agronomic traits such as dwarfism and pest and disease resistance. Australia’s undomesticated grass species (Poaceae) provide a unique and genetically diverse array of WCRs and therefore the grains of 17 Australian WCRs were examined by scanning electron microscopy (SEM). Aleurone of each WCR was compared with that of its nearest domesticated cereal relative, with little significant morphological variation observed to this structure. A novel subaleurone morphology was observed in the Sorghum WCRs which had the appearance of being a very dense protein matrix only sparsely embedded with small starch granules or completely lacking starch granules. Histochemical analysis of a subsample of the specimens confirmed that the described morphology was lacking starch granules and had a proteinaceous matrix. Such morphological variations within Australian wild crop relatives of commercial cereals may provide novel sources of genetic diversity for future grain improvement programs.


Author(s):  
Melisa B Bonica ◽  
Dario E Balcazar ◽  
Ailen Chuchuy ◽  
Jorge A Barneche ◽  
Carolina Torres ◽  
...  

Abstract Diseases caused by flaviviruses are a major public health burden across the world. In the past decades, South America has suffered dengue epidemics, the re-emergence of yellow fever and St. Louis encephalitis viruses, and the introduction of West Nile and Zika viruses. Many insect-specific flaviviruses (ISFs) that cannot replicate in vertebrate cells have recently been described. In this study, we analyzed field-collected mosquito samples from six different ecoregions of Argentina to detect flaviviruses. We did not find any RNA belonging to pathogenic flaviviruses or ISFs in adults or immature stages. However, flaviviral-like DNA similar to flavivirus NS5 region was detected in 83–100% of Aedes aegypti (L.). Despite being previously described as an ancient element in the Ae. aegypti genome, the flaviviral-like DNA sequence was not detected in all Ae. aegypti samples and sequences obtained did not form a monophyletic group, possibly reflecting the genetic diversity of mosquito populations in Argentina.


2021 ◽  
Vol 9 (2) ◽  
pp. e001684
Author(s):  
Rafael Moreno

The development of oncolytic viruses (OVs) has increased significantly in the past 20 years, with many candidates entering clinical trials and three of them receiving approval for some indications. Recently, OVs have also gathered interest as candidates to use in combination with immunotherapies for cancer due to their immunogenic properties, which include immunogenic cell death and the possibility to carry therapeutic transgenes in their genomes. OVs transform non-immunogenic ‘cold’ tumors into inflamed immunogenic ‘hot’ tumors, where immunotherapies show the highest efficacy. However, in monotherapy or in combination with immunotherapy, OVs face numerous challenges that limit their successful application, in particular upon systemic administration, such as liver sequestration, neutralizing interactions in blood, physical barriers to infection, and fast clearance by the immune system. In this regard, the use of mesenchymal stem cells (MSCs) as cells carrier for OV delivery addresses many of these obstacles acting as virus carriers and factories, expressing additional transgenes, and modulating the immune system. Here, I review the current progress of OVs-loaded MSCs in cancer, focusing on their interaction with the immune system, and discuss new strategies to improve their therapeutic efficacy.


2021 ◽  
Vol 54 (1) ◽  
pp. 1-22
Author(s):  
Rayan Chikhi ◽  
Jan Holub ◽  
Paul Medvedev

The analysis of biological sequencing data has been one of the biggest applications of string algorithms. The approaches used in many such applications are based on the analysis of k -mers, which are short fixed-length strings present in a dataset. While these approaches are rather diverse, storing and querying a k -mer set has emerged as a shared underlying component. A set of k -mers has unique features and applications that, over the past 10 years, have resulted in many specialized approaches for its representation. In this survey, we give a unified presentation and comparison of the data structures that have been proposed to store and query a k -mer set. We hope this survey will serve as a resource for researchers in the field as well as make the area more accessible to researchers outside the field.


2021 ◽  
Vol 13 (1-2) ◽  
pp. 29-76
Author(s):  
Juan Carlos Moreno García

Abstract Globalization, the decline of Western hegemony, and the rise of new political and economic actors, particularly in East Asia, are concomitant with the emergence of more encompassing historical perspectives, attentive to the achievements and historical trajectories of other regions of the world. Global history provides thus a new framework to understanding our past that challenges former views based on the cultural needs, values, and expectations of the West. This means that humanities and social sciences are subject to intense scrutiny and pressed to adapt themselves to a changing cultural, academic, and intellectual environment. However, this process is hindered by the gradual loss of their former prestige and by the increasing influence of economics in the reorganization of the educational, research, and cultural agenda according to market-oriented criteria. The result is that the mobilization of the past increasingly conforms to new strategies in which connectivity, trading, and diplomatic interests, as well as integration in dynamic flows of wealth, appear of paramount importance. Egyptology is not alien to these challenges, which will in all probability reshape its very foundations in the foreseeable future.


2020 ◽  
Vol 61 (1) ◽  
pp. 25-36
Author(s):  
Clayton G. Campbell ◽  
Mio Nagano

Buckwheat crop improvement by breeding has been taking place over the past 100 years or more. During this time there has been improvements in many desirable agronomic characteristics which has resulted in higher yields in many of the breeding programs. Phenotypic modifications, such as dwarf, semi-dwarf and branching have been reported. There has also been an effort to increase flower number as this has been shown in cross pollinating buckwheat, to increase yields. Flower cluster modifications and their effects on yield have also been studied. Increased reports on the discovery of buckwheat wild species have been reported from several programs with many interspecific crosses having taken place. Several of these crosses were performed with Fagopyrum esculentum in efforts to increase variability which can be used to increase yield potential as well as to obtain increased nutritional components.  More recent efforts have focused on the development of self-pollinating buckwheat, both from introgression of genes from Fagopyrum homotropicum as well as from mutations in cross pollinating buckwheat. The main problem has been in breeding depression which has occurred in many of the reported attempts. However, high yielding homomorphic, self-pollinating varieties have been developed and are now in commercial production. There is now emphasis being placed on many of the nutritional aspects of buckwheat flour as well as value added components. It is expected that this will increase over time.  Key words: Buckwheat breeding, homomorphic, autogamous buckwheat.   Izvleček Žlahtnjenje ajde poteka že več kot 100 let. V tem času je bila dosežena izboljšava željenih agronomskih lastnosti, kar je pri mnogih programih žlahtnjenja omogočilo večje pridelke. Raziskovalci poročajo o fenotipskih modifikacijah, kot je pritlikava ali pol-pritlikava rast in razvejanje. Za povečanje pridelka so bile raziskane modifikacije socvetij. Število poročil o odkritjih divjih sorodnikov ajde in o mnogih medvrstnih križanjih se je v zadnjem času povečalo. V mnoga od teh križanj je bila vključena navadna ajda (Fagopyrum esculentum), da bi povečali  variabilnost, kar bi lahko omogočilo povečanje pridelka in izboljšanje prehranskih lastnosti. Novejša prizadevanja so se osredotočila na razvoj samooplodnosti pri ajdi, z vključitvijo genov vrste Fagopyrum homotropicum, kot tudi mutacij pri ajdi, ki se je opraševala navzkrižno.  Pri tem je bila glavna težava preseči  depresijo zaradi samooploditev, depresija se je pojavila pri večih poskusih samooploditve. Ne glede na to je uspelo dobiti visokorodne homomorfne samooplodne sorte za ponudbo na trgu semen. Sedaj se prizadevanja usmerjajo k izboljšanju prehranske vrednosti ajde in pomembnih sestavin v ajdovi moki. Pričakovati je, da se bo pomen prehranske vrednosti ajde sčasoma še povečeval. Ključne besede: žlahtnjenje ajde, homomorfnost, samo­oplodna ajda


Genome ◽  
1995 ◽  
Vol 38 (1) ◽  
pp. 27-35 ◽  
Author(s):  
K. N. Watanabe ◽  
M. Orrillo ◽  
S. Vega ◽  
J. P. T. Valkonen ◽  
E. Pehu ◽  
...  

The first direct sexual hybrids between diploid nontuber-bearing species and diploid potato breeding lines are reported here. Three nontuberous species of Solanum, S. brevidens, S. etuberosum, and S. fernandezianum, were used for sexual crosses, achieved by a combination of rescue pollinations and embryo rescue. Initial hybrid selection was made using an embryo spot marker, followed by the evaluation of morphological and reproductive traits. Putative hybrids were first tested for resistance to potato leaf roll virus derived from the wild species, and then were tested with molecular markers using species-specific DNA probes. Finally, the tuberization of several 2x hybrids was tested for actual potato germplasm enhancement. These hybrids are unique in terms of their potential to enhance recombination between chromosomes of wild species and those of cultivated potatoes in germplasm utilization, and to exploit the genetic nature of tuber formation. The finding that nontuber-bearing Solanum spp. can be directly crossed with tuber-bearing species also has important implications for the regulatory aspects of the use of genetically modified organisms.Key words: nontuber-bearing Solanum, potato germplasm enhancement, interspecific crosses, chromosome manipulation, inter-EBN crosses, diploid.


2011 ◽  
Vol 89 (8) ◽  
pp. 732-743 ◽  
Author(s):  
B.J. Wilson ◽  
S.J. Crockford ◽  
J.W. Johnson ◽  
R.S. Malhi ◽  
B.M. Kemp

Many well-preserved bones of medium-sized goose have been recovered from the Zeto Point archaeological site (ADK-011) on Adak Island in the central Aleutians, Alaska, that date to ca. 170–415 years before present based on conventional radiometric dates of the deposits. This prehistoric sample includes remains of adults and unfledged goslings that defied confident identification based on osteological criteria. While the presence of newborns indicates that Adak was a breeding ground, which species was doing the nesting remained uncertain. Of the five species of medium-sized goose (order Anseriformes, family Anatidae) known or presumed to visit Adak Island, three are rarely sighted. The only common visitor is the Emperor Goose ( Chen canagica (Sevastianov, 1802)). The Aleutian Cackling Goose ( Branta hutchinsii leucopareia (Brandt, 1836)) breeds elsewhere in the Aleutians but does not currently breed on Adak Island and there are no records of it nesting there in the past. Here DNA sequences from portions of the cytochrome b (cytb) gene and the control region (CR) of the mitochondrial genome were recovered from 28 of 29 Adak prehistoric goose remains. All adult specimens identified to species were either C. canagica or B. h. leuopareia, but all specifically identified juvenile specimens were B. h. leuopareia. The results demonstrate that Adak Island was a breeding ground of the Aleutian Cackling Goose prior to European contact.


Sign in / Sign up

Export Citation Format

Share Document