Genetic structure and mating system of Oryza glumaepatula steud. populations using microsatellite markers

As informações existentes em torno da estrutura genética e do sistema reprodutivo das populações de Oryza glumaepatula são poucas e ainda precárias. Este estudo teve como objetivo caracterizar a estrutura genética de 11 populações provenientes dos Rios Japurá, Solimões, Purus, Negro, Xingú e Tapajós (provenientes da bacia Amazônica) e dos Rios Paraguai e Taquari (provenientes da bacia do Paraguai) amostrando-se 30 indivíduos por população e avaliar o sistema reprodutivo em três dessas populações (SO-6, XI-1 e PG-1) a partir de 10 progênies maternas, com 10 plantas por progênie, em cada população. O DNA dos indivíduos foi extraído, quantificado e avaliado com base em oito locos de microssatélites e uma média de 10 alelos/loco. Estimaram-se parâmetros de diversidade genética, as estatísticas F e o fluxo gênico, verificando-se a existência de estruturação espacial, por meio do coeficiente de correlação de Pearson (r), e teste de Mantel. O sistema reprodutivo foi avaliado pela taxa de cruzamento aparente (nas populações) e pela taxa multilocos para as famílias das três populações. Obtiveram-se as seguintes estimativas de parâmetros genéticos: 77,3% de locos polimórficos; Ho (heterozigosidade observada média)= 0,091; He (diversidade gênica) = 0,393; FST = 0,491 (e RST = 0,608); FIS = 0,780 e FIT = 0,888. Nenhuma população foi encontrava-se em equilíbrio de Hardy-Weinberg. A taxa média de cruzamento aparente foi de t a = 0,124 sugerindo sistema misto de reprodução com tendência a autogamia. Uma exceção foi a população do Rio Xingu (XI-1) que apresentou menos autogamia com ta = 0,454, Ho = 0,233, He = 0,369 e o mais baixo índice de fixação f = 0,371. Os resultados indicam haver grande diversidade genética entre as populações bem como níveis variáveis de autofecundação natural. As populações não se encontraram estruturadas no espaço, pois foi nula a correlação entre distâncias genéticas e geográficas (r = 0,03). O estudo do sistema reprodutivo foi baseado num número médio menor de alelos por loco e forneceu as seguintes estimativas para as três populações (XI-1, SO-6 e PG-1), respectivamente: número médio de alelos por loco: 3, 3 e 5; endogamia das plantas-mãe ( F m): 0,399, 0,846 e 0,631; taxas de cruzamentos multiloco ( t m): 0,160, 0,011 e 0,223; uniloco ( t s): 0,078, 0,003 e 0,100; cruzamento biparental ( t m - t s): 0,083, 0,008 e 0,123; coeficiente de coancestria ( θfam): 0,711, 0,846 e 0,748. Os resultados confirmam a desuniformidade no sistema reprodutivo das populações, que variou de autogamia absoluta até taxas de cruzamento de 22,3%. Essa desuniformidade bem como a alta diversidade genética interpopulacional e a ausência de estruturação espacial indicam que atividades de conservação devem abranger o maior número possível de populações.Informations about genetic structure and breeding systems are little and poorly of natural O. glumaepatula populations. The objective of this study was the characterization of the genetic structure of 11 populations from Japura, Solimoes, Purus, Negro, Xingu and Tapajos rivers (from Amazon Hidrographic Basin) and from Paraguai and Taquari rivers (from Paraguai Hidrographic Basin), sampling 30 individuals per population and analisys of breeding system of three populations SO-6, XI-1 and PG-1, from 10 mother progeny with 10 plants per progeny in each population. Individuals DNA were extracted quantified and analyzed utilizing eigth microsatellite loci with a mean of 10 alleles per loci. Genetic diversity parameters, Wrights F-statistics and gene flow were stimated. Space structure was also verified using Pearsons correlation coefficient (r) and Mantels test. The breeding system was examined by the apparent outcrossing rate (in the populations) and multilocus outcrossing rate obtained for the progenies of three populations.The following estimates of parameters were obtained: 77.3% polymorphic loci; Ho (observed heterozigosity) = 0.091; He (diversidade gênica) = 0.393; FST = 0.491 (e RST = 0.608); FIS = 0.780 e FIT = 0.888. Neither population was in Hardy-Weinber equilibrium. The average of apparent outcrossing rate was t a = 0.124, suggesting mixed mating system with predominance of inbreeding. One exception was the Xingus river population (XI-1), which have presented the lowest autogamy indices with ta = 0.459, Ho = 0.233, He = 0.369, and the lowest fixation index f = 0.371. These results pointed for a high genetic divesity between populations also variable natural inbreeding degrees. These populations were not structured on space, because were null the correlations between genetic and geographic distances (r = 0.003). The study of breeding system was based on lowest average alleles number per loci and to provide the following estimates for the three populations (XI-1, SO-6 e PG-1) respectively: average number of alleles per loci: 3, 3 and 5; maternal inbreeding ( F m): 0.399, 0.846 and 0.631; multilocus outcrossing rate ( t m): 0.160, 0.011 and 0.223; single-locus ( t s): 0.078, 0.003 and 0.100; biparental inbreeding ( t m - t s): 0.083, 0.008 and 0.123; coancestry coefficient ( θfam): 0.711, 0.846 and 0.748. These results confirm the population desuniform mating system, which had varied from perfect autogamy to 22.3% of outcrossing rates. That desuniformity as well as the high interpopulation genetic diversity and the absence of space structuring indicate that conservation activities should include the largest possible number of populations

Current challenges in plant breeding to achieve zero hunger and overcome biotic and abiotic stresses induced by the global climate changes: A review

According Sustainable Development goals until 2030 we should have zero hunger and undernourished people in the world. But to achieve this goal plant breeders must improve plants in order to produce at least the double than is produced now. This is not a easy pathway because we have only few years, but considering that plant breeding programs normally take several years to produce improved genotypes, also the further improved plants should face with pest, disease and other abiotic factors that are increasing with the current climate changes. In this review we will discuss the situation of hunger in the world and the remaining available land to increase food production, point out effects of biotic and abiotic factors on the food production and present some ways that can be used to fastening plant breeding

Fruits as Prospective Reserves of bioactive Compounds: A Review

Abstract Bioactive natural products have always played a significant role as novel therapeutical agents irrespective of their source of origin. They have a profound effect on human health by both direct and indirect means and also possess immense medicinal properties. Fruit species are largely appreciated and highly consumed throughout the world. Epidemiologic information supports the association between high intake of fruits and low risk of chronic diseases. There are several biological reasons why the consumption of fruits might reduce or prevent chronic diseases. Fruits are rich sources of nutrients and energy, have vitamins, minerals, fiber and numerous other classes of biologically active compounds. Moreover, parts of the fruit crops like fruit peels, leaves and barks also possess medicinal properties and have been included in this review. The most important activities discussed in this review include antidiabetic, anticancer, antihypertensive, neuroprotective, anti-inflammatory, antioxidant, antimicrobial, antiviral, stimulation of the immune system, cell detoxification, cholesterol synthesis, anticonvulsant and their ability to lower blood pressure. Several phytochemicals involved in this context are described with special emphasis on their structural properties and their relativity with human diseases

Gametic embryogenesis through isolated microspore culture in Corylus avellana L.

Haploid technology is a valuable plant breeding tool for obtaining homozygosity particularly in woody plants. Hazelnut, the world’s sixth ranking nut tree crop is a monoecious, anemophilous species. It is characterized by a sporophytic incompatibility system that prevents production of homozygous plants with conventional methods, involving several self-pollination cycles. In this study, gametic embryogenesis, in particular isolated microspore culture, was tried with five genotypes. Two culture media were tested and four temperature stress treatments were applied to the isolated microspores that were cultivated at the vacuolated developmental stage. To our knowledge, this is the first report of early embryos being recovered from the five hazelnut genotypes via isolated microspore culture. Analysis of the embryo genotypes using SSR markers demonstrated the embryos had a single allele per each locus whereas the parent cultivar was heterozygous, indicating they developed from haploid microspores. The response to the culture treatments, was, however, genotype-dependent, as previously reported for male gamete embryogenesis in other fruit crops

Early embryo achievement through isolated microspore culture in Citrus clementina Hort. ex Tan., cvs. ‘Monreal Rosso’ and ‘Nules’

10 p.-5 fig.-3 tab.Microspore embryogenesis is a method of achieving complete homozygosity from plants. It is particularly useful for woody species, like Citrus, characterized by long juvenility, a high degree of heterozygosity and often self-incompatibility. Anther culture is currently the method of choice for microspore embryogenesis in many crops. However, isolated microspore culture is a better way to investigate the processes at the cellular, physiological, biochemical, and molecular levels as it avoids the influence of somatic anther tissue. To exploit the potential of this technique, it is important to separate the key factors affecting the process and, among them, culture medium composition and particularly the plant growth regulators and their concentration, as they can greatly enhance regeneration efficiency. To our knowledge, the ability of meta-Topolin, a naturally occurring aromatic cytokinin, to induce gametic embryogenesis in isolated microspores of Citrus has never been investigated. In this study, the effect of two concentrations of meta-Topolin instead of benzyladenine or zeatin in the culture medium was investigated in isolated microspore culture of two genotypes of Citrus. After 11 months of isolated microspore culture, for both genotypes and for all the four tested media, the microspore reprogramming and their sporophytic development was observed by the presence of multinucleated calli and microspore-derived embryos at different stages. Microsatellite analysis of parental and embryo samples was performed to determine the embryo alleles constitution of early embryos produced in all tested media, confirming their origin from microspores. To our knowledge, this is the first successful report of Citrus microspore embryogenesis with isolated microspore culture in Citrus, and in particular in Citrus clementina Hort. ex Tan, cvs. ‘Monreal Rosso’ and ‘Nules.’This work was partially supported by “Functional genomics, genetic improvement, and innovation for the valorization of Citrus industry” IT-Citrus Genomics project (PON01_01623) funded by the Italian MIUR (Ministero dell’Istruzione, dell’Università e della Ricerca) PON Research and Competitiveness 2007–2013 and UE, projects BFU2008-00203 and AGL2014-52028-R funded by the Spanish Ministry of Economy and Competitiveness (MINECO) and the European Regional Development Fund(ERDF/FEDER).Peer reviewe