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- Population decline in the critically endangered Musschia isambertoi (Campanulaceae) endemic to Desertas Islands (Madeira Archipelago) calls for urgent conservation managementPublication . Sequeira, M. Menezes de; Jardim, R.; Gouveia, M.; Góis-Marques, C. A.; Eddie, W. M. M.Macaronesian islands display a high degree of plant endemicity and correspond to some of the most threatened biodiversity hotspots due to several human driven impacts such as habitat loss, invasive species, overexploitation or climate change. The conservation status of the largest of the two known population of Musschia isambertoi M. Seq., R. Jardim, Magda Silva and L. Carvalho (Campanulaceae) was assessed recently. Field work was done in June 2018 in “Porto das Moças” Deserta Grande (Madeira Archipelago, Portugal), the locus typicus, where in 2006 close to 30 plants were detected with a high variation of age/size between individuals comprising both fully flowering and non-flowering adult plants as well as seedlings, and thus corresponding to a healthy population. This study assesses population size, age and plant size, and genetic, as well as floristic diversity. The total area of the site corresponds to approximately 1500 square meters. Ten individuals were detected, all corresponding to young seedlings not exceeding 15 cm high, and exhibiting approximately the same size and numbers of leaves (4–8). No adult plants or remains of adult plants were seen. Ecological data and direct herbivory evidence suggest that perennial plants are subjected to elimination during the short summer by the feral goat population. Mo lecular data based on ISSR markers show that the nine sampled individuals (out of ten individuals found) are genetically identical, possibly resulting from one parental plant. Results clearly suggest that Musschia isambertoi is very close to extinction. Urgent conservation measures are imperative and should include the immediate fencing of the population followed by the elimination of feral goats from Deserta Grande. The elimination of feral goats was initiated in 1996 (LIFE95 NAT/P/000125, 383,467.00 €) but stopped due to inappropriate conser vation policies of the former Services of the Natural Park of Madeira.
- Heat shock-induced susceptibility of green coffee leaves and berries to Colletotrichum gloeosporioides and its association to PR and hsp70 gene expressionPublication . Chen, Z. J.; Ribeiro, A.; Silva, M. C.; Santos, P.; Guerra-Guimarães, L.; Gouveia, M.; Fernandez, D.; Rodrigues, C. J.Colletotrichum kahawae Bridge & Waller and C. gloeosporioides Penz are both coffee (Coffea arabica L.) pathogens but only the former induces damages on green coffee berries causing 70–80% losses, being known as coffee berry disease or CBD. The latter infects only very ripe coffee berries without destroying the seed but is also responsible for ‘dieback’ of branches in overbearing seasons. Detached green coffee berries and leaves inoculated with C. kahawae show usually symptoms 4–5 days after inoculation. With C. gloeosporioides penetration does not even occur. However, when green berries and leaves were subject to a previous heat shock of 55 8C for 30 s and then inoculated, there was a total breakdown of resistance regarding C. gloeosporioides and an acceleration of the infection process regarding C. kahawae. Heat shock induced susceptibility decreased with time for both fungi and became null about 40–48 h after the treatment for C. gloeosporioides. The temporary loss of resistance was associated with a transient downregulation of some PR genes, namely cachi3-1, cachi4-1 and capox-1, and by a transient upregulation of cahsp70. All genes analysed under this study were expressed constitutively, two of them, cachi3-1 and cachi4- 1, being up-regulated in inoculated controls. It is suggested that the synergistic presence of these constitutive defenses may be one of the mechanisms used by the plant to control resistance to C. gloeosporioides. Moreover we hypothesise that the protein coded by cahsp70 could facilitate the penetration of the pathogen. To our knowledge, this is the first time that the expression of PRs and Hsp70 coding genes is associated to heat shock-induced susceptibility.
- Molecular, morphological and agronomic characterization of the sweet potato (Ipomoea batatas L.) germplasm collection from Mozambique: Genotype selection for drought prone regionsPublication . Maquia, I.; Muocha, I.; Naico, A.; Martins, N.; Gouveia, M.; Andrade, I.; Goulao, L. F.; Ribeiro, A. I.Sweet potato (Ipomoea batatas (L.) Lam) is one of the most important root crops in Mozambique, ranking in the 3rd position, after cassava and maize. Within the scope of the national and regional strategies/initiatives, we have used a multi-analysis approach to characterize the national sweet potato germplasm collection at two different levels: i) genetic, morphological and agronomic diversity; and ii) agronomic potential (storage root yield, vine weight, biomass, harvest index and dry matter content) toward drought tolerance. This collection, composed by 44 accessions, comprises 28 genotypes cultivated in three different provinces of Mozambique (Gaza, Inhambane and Zambezia), nine from other African countries (Kenya, South Africa, Uganda and Zimbabwe), one from the United States of America, and six from CGIAR research centers (IITA and CIP). According to our results, the Mozambican germplasm bank presents a high level of diversity, comparable to those from the collections of the primary centers of origin and South Africa, therefore constituting of a good source of agronomic traits for breeding. Regarding drought tolerance, six Mozambican genotypes (Admarc, Chingova, Nhacoongo-1, Xihetamakote, Nwanatuyo, and Chissicuana-2), one from Uganda (NASPOT-5), one from Zimbabwe (Moz_white), one from Kenya (SPK 004), and one from the USA (Resisto) seem to have the highest potential to be used in regions with frequent drought seasons and in future breeding programs. The results showed that such integrated analysis can be used to successfully characterize the genetic material in terms of suitability to drought-prone regions, there fore helping sweet potato crop management, with economic and food security impacts.
- Population structure and genetic diversity of wild Helianthus species from MozambiquePublication . Ribeiro, A.; Gouveia, M.; Bessa, A.; Ferreira, A.; Magumisse, A. T.; Manjate, M.; Faria, T.The production of sunflower suffered a major decline in Mozambique after its independence in 1975. Civil war, human activities and environmental damage subjected the species to an ecological stress con tributing to reduce the number and size of wild populations. As this reduction is often related to a loss of genetic variation we estimated the genetic diversity within and among populations of wild Helianthus from five districts of Mozambique using RAPD markers. The 44 accessions studied grouped into four major clusters exhibiting structured variability with regard to geographic origin. A high level of genetic diversity (He = 0.350 and I = 0.527) was retained at the population level. The genetic variation among populations was high (59.7%), which is consistent with low gene flow (Nm = 0.338). The proportion of total genetic diversity resid ing among these populations should be kept in mind to devise different conservation strategies in order to pre serve these populations. Currently wild Helianthus genetic resources present in Maputo and Sofala are on the edge of extinction mainly due to excessive urbanization. Therefore, conservation of what remains of this plant genetic diversity is essential for sustainable utilization and can be useful for breeding programs.
- Nematicidal activity of Solanum sisymbriifolium and S-nigrum extracts against the root-lesion nematode Pratylenchus goodeyiPublication . Pestana, M.; Rodrigues, M.; Teixeira, L.; Abrantes, I. M. de O.; Gouveia, M.; Cordeiro, NereidaThe root-lesion nematode, Pratylenchus goodeyi, is a parasite of banana plants, frequently detected in Madeira Island (Portugal) affecting culture development and consequently the production, with economical damages. To identify the phytochemicals of Solanum sisymbriifolium and S. nigrum with nematicidal properties and determine the effect of those components on P. goodeyi, an extraction sequence of at least 10 hours each from dried plants was used. The chosen solvent sequence was: dichloromethane, acetone, ethanol and water. According to the results, both plants have in their composition chemical components mainly found in water extracts, which affects the mobility and mortality of the root-lesion nematode. S sisymbriifolium and S. nigrum have potential to be used as a natural and environmentally friendly nematicide to control P. goodeyi.
- Effect of chemical stress imposed by Solanum nigrum in calreticulin and beta-1,4- endoglucanase genes and in infectivity of Pratylenchus goodeyiPublication . Pestana, M.; Abrantes, I.; Gouveia, M.Isolation and expression of effector genes encoding proteins secreted by plant-parasitic nematodes into a host can be helpful in improving the understand ing of parasitic interactions. In this study, calreticulin, a highly conserved Ca2+-binding and multifunctional pro tein, and beta-1,4-endoglucanase, a cell wall-degrading enzyme, both known to be secreted from oesophageal gland cells and injected through the nematode stylet into host tissue, were analysed. Full-length cDNAs from calreticulin (crt) and beta-1,4-endoglucanase (eng) with an estimated size of 1549 and 1342 bp, respectively, were isolated from the root-lesion nematode Pratylenchus goodeyi (Pg) by RT-PCR and RACE tech niques. Pg-crt and Pg-eng cDNAs were characterized in silico, and their expression assessed by semi quantitative PCR in nematodes exposed to a chemical stress provided by a Solanum nigrum extract showing nematicidal activity. It was demonstrated that the plant extract down-regulated the levels of Pg-crt mRNA, whereas the transcripts of Pg-eng mRNA held steady. This extract also affected nematode behaviour towards the roots since the number of nematodes that reached and penetrated the roots diminished when the exposure time rose. These observations indicate that the nemati cidal compounds present in the plant extract were effec tive as a signal to influence the infection success of P. goodeyi in vitro and it might be tested against other phytoparasitic nematodes.