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Michael?FreiEmail author Richmond?Narh?Tetteh Ando?Lalaina?Razafindrazaka Michael?Apolonius?Fuh Lin-Bo?Wu Mathias?Becker 《Plant and Soil》2016,408(1-2):149-161
Background and aims
Iron (Fe) toxicity is a wide-spread stress in lowland rice production. The aim of this study was to differentiate between responses to acute Fe stress during the vegetative stage and chronic Fe stress throughout the growing period.Methods
Six rice genotypes were tested in a semi-artificial greenhouse setup, in which acute (almost 1500 mg L?1 Fe in soil solution during the vegetative stage) and chronic (200 to 300 mg L?1 Fe throughout the season) Fe toxicity were simulated.Results
Acute Fe stress induced early development of heavy leaf bronzing, whereas moderate symptoms occurred in the chronic treatment throughout the season. Grain yields were only reduced in the chronic stress treatment (?23 %) due to reductions in spikelet fertility, grain number and grain weight. Symptom formation during the early growth stages did not reflect yield responses in all genotypes. Only one genotype showed increases in grain Fe concentrations (24 % in the acute stress and 44 % in the chronic stress) compared to the control.Conclusions
Contrasting genotypes responded differently to acute and chronic Fe toxicity, and one genotype showed consistent tolerance and the ability to translocate excess Fe into grains. These traits can be useful in the adaptive breeding of rice for Fe toxic environments.2.
Pradiptajati Kusuma Murray P Cox Denis Pierron Harilanto Razafindrazaka Nicolas Brucato Laure Tonasso Helena Loa Suryadi Thierry Letellier Herawati Sudoyo Fran?ois-Xavier Ricaut 《BMC genomics》2015,16(1)
Background
Linguistic, cultural and genetic characteristics of the Malagasy suggest that both Africans and Island Southeast Asians were involved in the colonization of Madagascar. Populations from the Indonesian archipelago played an especially important role because linguistic evidence suggests that the Malagasy language branches from the Southeast Barito language family of southern Borneo, Indonesia, with the closest language spoken today by the Ma’anyan. To test for a genetic link between Malagasy and these linguistically related Indonesian populations, we studied the Ma’anyan and other Indonesian ethnic groups (including the sea nomad Bajo) that, from their historical and linguistic contexts, may be modern descendants of the populations that helped enact the settlement of Madagascar.Result
A combination of phylogeographic analysis of genetic distances, haplotype comparisons and inference of parental populations by linear optimization, using both maternal and paternal DNA lineages, suggests that Malagasy derive from multiple regional sources in Indonesia, with a focus on eastern Borneo, southern Sulawesi and the Lesser Sunda islands.Conclusion
Settlement may have been mediated by ancient sea nomad movements because the linguistically closest population, Ma’anyan, has only subtle genetic connections to Malagasy, whereas genetic links with other sea nomads are more strongly supported. Our data hint at a more complex scenario for the Indonesian settlement of Madagascar than has previously been recognized.Electronic supplementary material
The online version of this article (doi:10.1186/s12864-015-1394-7) contains supplementary material, which is available to authorized users. 相似文献3.
Henriette Rasolofoarivao Johanna Clémencet Lala Harivelo Raveloson Ravaomanarivo Dimby Razafindrazaka Bernard Reynaud Hélène Delatte 《Experimental & applied acarology》2013,60(4):521-530
Varroa destructor is a major pest in world beekeeping. It was first detected in Madagascar in 2010 on the endemic honeybee Apis mellifera unicolor. To evaluate V. destructor spread dynamics in Madagascar a global survey was conducted in 2011–2012. A total of 695 colonies from 30 districts were inspected for the presence of mites. 2 years after its introduction, nine districts were found infested. Varroa destructor spread was relatively slow compared to other countries with a maximum progression of 40 km per year, the five newly infested districts being located next to the first infested ones. The incidence of mite infestation was also investigated by monitoring 73 colonies from five apiaries during 1 year (2011–2012). Sixty percent of local colony mortality was recorded after 1 year of survey. Varroa destructor strain determination was done by partial sequencing of the cytochrome oxidase I gene of 13 phoretic mites sampled in five districts. A single V. destructor mitochondrial haplotype was detected, the Korean type, also present in the closest African countries. A global pathogen survey was also conducted on the colonies inspected for mite presence. The greater wax moth, Galleria mellonella has been found in all colonies all over the country. Two other pathogens and morphological abnormalities in workers, such as deformed wings, were found associated with only V. destructor presence. A prevention management plan must be implemented to delimit mite spread across the island. 相似文献
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Rahajanirina V Raoseta SO Roger E Razafindrazaka H Pirotais S Boucher M Danthu P 《Chemistry & biodiversity》2012,9(2):298-308
Centella asiatica (Apiaceae family; Talapetraka in Malagasy) is a tropical and subtropical plant with leaves containing glycotriterpenoids (asiaticosides) used in traditional and modern medicine. C. asiatica is collected exclusively in natural stands. It is Madagascar's second most important indigenous plant export. The objective in this study is to provide data which will make it possible to optimize the harvest and thus effectively develop this resource. Two foliar morphotypes were identified: morphotype A with small reniform leaves (leaf area ca. 4.5 cm(2) ), found in the east of Madagascar, and morphotype B with large round leaves (up to 7.5 cm(2) ) found in the west, with sympatric zones in the central part of the island. Morphotype A produces a higher biomass, and is twice as rich in asiaticosides as morphotype B. Significant variations in biomass yield and asiaticoside content are observed depending on the date of collection: higher during the rainy season (December to April) and lower during the dry season (June to August). Inter-annual variations are also observed. Populations located at around 800-1400 m altitude on the eastern side of Madagascar, in a sub-humid climate, appeared to be more productive. These results provide more precise information to the economic sector, which confirms the empirical choices made by collectors. They represent the first elements towards sustainable management of the resource, and maybe even domestication. 相似文献
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Denis Pierron Harilanto Razafindrazaka Christophe Rocher Thierry Letellier Lawrence I. Grossman 《Molecular genetics and genomics : MGG》2014,289(1):37-45
Recent studies have suggested that selective forces and constraints acting on genes varied during human evolution depending on the organ in which they are expressed. To gain insight into the evolution of organ determined negative selection forces, we compared the non-synonymous SNP diversity of genes expressed in different organs. Based on a HAPMAP dataset, we determined for each SNP its frequency in 11 human populations and, in each case, predicted whether or not the change it produces is deleterious. We have shown that, for all organs under study, SNPs predicted to be deleterious are present at a significantly lower frequency than SNPs predicted to be tolerated. However, testis-specific genes contain a higher proportion of deleterious SNPs than other organs. This study shows that negative selection is acting on the whole human genome, but that the action of negative selection is relaxed on testis-specific genes. This result adds to and expands the hypothesis of a recent evolutionary change in the human male reproductive system and its behavior. 相似文献
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Mélanie Capredon Nicolas Brucato Laure Tonasso Valérie Choesmel-Cadamuro Fran?ois-Xavier Ricaut Harilanto Razafindrazaka Andriamihaja Bakomalala Rakotondrabe Mamisoa Adelta Ratolojanahary Louis-Paul Randriamarolaza Bernard Champion Jean-Michel Dugoujon 《PloS one》2013,8(11)
Madagascar is located at the crossroads of the Asian and African worlds and is therefore of particular interest for studies on human population migration. Within the large human diversity of the Great Island, we focused our study on a particular ethnic group, the Antemoro. Their culture presents an important Arab-Islamic influence, but the question of an Arab biological inheritance remains unresolved. We analyzed paternal (n=129) and maternal (n=135) lineages of this ethnic group. Although the majority of Antemoro genetic ancestry comes from sub-Saharan African and Southeast Asian gene pools, we observed in their paternal lineages two specific haplogroups (J1 and T1) linked to Middle Eastern origins. This inheritance was restricted to some Antemoro sub-groups. Statistical analyses tended to confirm significant Middle Eastern genetic contribution. This study gives a new perspective to the large human genetic diversity in Madagascar. 相似文献
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Felana Harilanto Andrianjakarivony Yvan Bettarel Philippe Cecchi Sonia Bouchard Emily Chase Christelle Desnues 《Environmental microbiology》2023,25(11):2368-2387
Human and livestock sewage is one of the major causes of excess nutrients, leading to the eutrophication of aquatic ecosystems and potentially to the emergence or spread of pathogenic viruses. This study aimed to investigate the composition and diversity of aquatic viromes in a highly anthropized lagoon, to identify the presence of pathogenic taxa and to explore their use as possible viral indicators of faecal contamination. For this, water and sediment samples were collected in the Ebrié Lagoon (Ivory Coast) at seven stations with contrasting levels of eutrophication. The DNA viromes of the planktonic and the benthic compartments were highly divergent, but were not influenced by the level of eutrophication. Conversely, the RNA viromes in the water column were comparable to those found in sediment, but showed significant differences between the stations. We detected the presence of viral DNA and RNA sequences we had assigned as indicators of faecal contamination (smacovirus, pecovirus and pepper mild mottle virus) as well as human pathogens (human cyclovirus, coxsackie B virus and picobirnavirus), which were all enriched in the most eutrophicated sites. These findings suggest that the examination of viromes represents a promising tool for assessing the state of human-induced contamination of aquatic ecosystems. 相似文献
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