The diversity of Botryosphaeriaceae species associated with“Botryosphaeria dieback”of grapevine was investigated in 18 vineyards in Sardinia,Italy.Lasiodiplodia isolates obtained from different woody hosts including...The diversity of Botryosphaeriaceae species associated with“Botryosphaeria dieback”of grapevine was investigated in 18 vineyards in Sardinia,Italy.Lasiodiplodia isolates obtained from different woody hosts including holm oak,sweet orange and broom bush in Italy,Algeria and Tunisia were also characterized.Morphological and cultural characteristics as well as ITS and EF1-αsequence data were used to identify the fungal isolates.Forty-eight botryosphaeriaceous isolates were obtained from 113 symptomatic grapevine samples,from which ten species were identified.Diplodia seriata was the dominant species(25%of isolates),followed by Neofusicoccum parvum(21.7%).Two species,Diplodia olivarum and D.africana are reported for the first time on grapevine.In addition,two new species namely Lasiodiplodia mediterranea sp.nov.from grapevine,holm oak and sweet orange and Lasiodiplodia exigua sp.nov.from broom bush are described.In artificial inoculation experiments conducted on excised green grapevine shoots and lignified canes as well as holm oak seedlings,L.mediterranea was shown to be an aggressive pathogen.展开更多
A total of 20 rhizobial isolates obtained from root-nodules of Retama raetam （Forsk） and Lupinus various （L.） were studied for their ability to tolerate local environmental and chemical stresses. Six fast and one ...A total of 20 rhizobial isolates obtained from root-nodules of Retama raetam （Forsk） and Lupinus various （L.） were studied for their ability to tolerate local environmental and chemical stresses. Six fast and one slow growing reference strains were included for comparison. Numerical analysis showed that the reference strains were separated from test isolates. The majority of isolates displayed a high tolerance to extreme temperatures; some even grew at 48 ℃ and grew at alkaline and acid pH. Regarding tolerance to salinity on agar medium, the majority of the isolates grew at 6% NaCl, but some isolates from Lupinus various were more resistant, grew even at 8% NaCl. Most isolates were resistant to heavy metals, but were sensitive to most antibiotics tested.展开更多
Aims The survival and ecological distribution of plants in arid habitats are mainly conditioned by water availability and physiological adaptations to withstand drought.In the present study,we have compared the physio...Aims The survival and ecological distribution of plants in arid habitats are mainly conditioned by water availability and physiological adaptations to withstand drought.In the present study,we have compared the physiological responses to drought of two Retama raetam(retama)subspecies from Tunisia,one of them living under the desert climate(subsp.raetam)and the other one growing on the coast(subsp.bovei).Methods To physiologically characterize the two R.raetam subspecies,and to elucidate their main mechanisms underlying their tolerance to drought stress,parameters related to seed germination,growth,photosynthesis(net photosynthetic rate,intracellular CO_(2) concentration,transpiration rate,stomatal conductance and water-use efficiency)and accumulation of osmolytes(proline,glycine betaine[GB]and soluble sugars)were determined in 4-month-old plants subjected to stress for up to 1 month.Important Findings Drought significantly inhibited germination,growth and all the evaluated photosynthetic parameters.Plants of R.raetam subsp.bovei were severely affected by drought after 3 weeks of treatment when photosynthesis rates were up to 7-fold lower than in the controls.At the same time,proline and GB significantly accumulated compared with the irrigated controls,but much less than in R.raetam subsp.raetam;in the latter subspecies,proline and GB increased to levels 24-and 6-fold higher,respectively,than in the corresponding controls.In summary,the population living in the desert region exhibited stronger tolerance to drought stress than that adapted to the semiarid littoral climate,suggesting that tolerance in R.raetam is dependent on accumulation of osmolytes.展开更多
Atlantic forest natural soil flora was tested on two leguminous pioneer species Acacia gummifera and Retama monosperma to be used in rehabilitation programs of the coastal sand dunes forest of the Essaouira region.The...Atlantic forest natural soil flora was tested on two leguminous pioneer species Acacia gummifera and Retama monosperma to be used in rehabilitation programs of the coastal sand dunes forest of the Essaouira region.The rhizospheric soil of two endemic plant species:R.nonosperma and Juniperus phoenicea was sampled and split into two categories,one from native rhizospheric soil,the other of the sterilized rhizospheric soil.Investigation was focused on mycorrhizal formations,but other forms of beneficial symbiosis such as rhizobia and viable soil microflora were also studied.Growth and nutrition variables assessed included lengths of roots and shoots,number of branches,ratio of root to shoot dry mass and water,nitrogen and phosphorus levels.Results showed important mycorrhizal associations in roots of both plants,presence of nodules and abundance of viable soil microflora.J.phoenicea had a 100%frequency of mycorrhizal formation and an intensity of 80%compared to a frequency of 80%and intensity of 54%for R.monosperma.Nodules had the same density of CFU regardless of the origin.Abundance of viable microflora in rhisospheric soil of R.monosperma,J.phoenicea and the control differed significantly.Among the studied variables for A.gummifera and R.monosperma,nitrogen and phosphorus uptakes significantly wit the use of the nonsterilized rhizospheric soil.Both species doubled their phosphorus uptake when colonized by mycorrhizal species,R.monosperma doubled its nitrogen uptake and A.gummifera increased it by seven times compared with the control.No significant difference was noted for the other variables.展开更多
基金Antonio Deidda and Bruno Scanu gratefully acknowledge Sardinia Regional Government for the financial support of the PhD scholarship and research grant,respectively(P.O.R.Sardegna F.S.E.Operational Programme of the Autonomous Region of Sardinia,European Social Fund 2007–2013-Axis IV Human Resources,Objective l.3,Line of Activity l.3.1.).
文摘The diversity of Botryosphaeriaceae species associated with“Botryosphaeria dieback”of grapevine was investigated in 18 vineyards in Sardinia,Italy.Lasiodiplodia isolates obtained from different woody hosts including holm oak,sweet orange and broom bush in Italy,Algeria and Tunisia were also characterized.Morphological and cultural characteristics as well as ITS and EF1-αsequence data were used to identify the fungal isolates.Forty-eight botryosphaeriaceous isolates were obtained from 113 symptomatic grapevine samples,from which ten species were identified.Diplodia seriata was the dominant species(25%of isolates),followed by Neofusicoccum parvum(21.7%).Two species,Diplodia olivarum and D.africana are reported for the first time on grapevine.In addition,two new species namely Lasiodiplodia mediterranea sp.nov.from grapevine,holm oak and sweet orange and Lasiodiplodia exigua sp.nov.from broom bush are described.In artificial inoculation experiments conducted on excised green grapevine shoots and lignified canes as well as holm oak seedlings,L.mediterranea was shown to be an aggressive pathogen.
文摘A total of 20 rhizobial isolates obtained from root-nodules of Retama raetam （Forsk） and Lupinus various （L.） were studied for their ability to tolerate local environmental and chemical stresses. Six fast and one slow growing reference strains were included for comparison. Numerical analysis showed that the reference strains were separated from test isolates. The majority of isolates displayed a high tolerance to extreme temperatures; some even grew at 48 ℃ and grew at alkaline and acid pH. Regarding tolerance to salinity on agar medium, the majority of the isolates grew at 6% NaCl, but some isolates from Lupinus various were more resistant, grew even at 8% NaCl. Most isolates were resistant to heavy metals, but were sensitive to most antibiotics tested.
基金Dhikra Zayoud's stay in Valencia was supported by a grant from the Tunisian Ministry of Higher Education and Scientific Research.
文摘Aims The survival and ecological distribution of plants in arid habitats are mainly conditioned by water availability and physiological adaptations to withstand drought.In the present study,we have compared the physiological responses to drought of two Retama raetam(retama)subspecies from Tunisia,one of them living under the desert climate(subsp.raetam)and the other one growing on the coast(subsp.bovei).Methods To physiologically characterize the two R.raetam subspecies,and to elucidate their main mechanisms underlying their tolerance to drought stress,parameters related to seed germination,growth,photosynthesis(net photosynthetic rate,intracellular CO_(2) concentration,transpiration rate,stomatal conductance and water-use efficiency)and accumulation of osmolytes(proline,glycine betaine[GB]and soluble sugars)were determined in 4-month-old plants subjected to stress for up to 1 month.Important Findings Drought significantly inhibited germination,growth and all the evaluated photosynthetic parameters.Plants of R.raetam subsp.bovei were severely affected by drought after 3 weeks of treatment when photosynthesis rates were up to 7-fold lower than in the controls.At the same time,proline and GB significantly accumulated compared with the irrigated controls,but much less than in R.raetam subsp.raetam;in the latter subspecies,proline and GB increased to levels 24-and 6-fold higher,respectively,than in the corresponding controls.In summary,the population living in the desert region exhibited stronger tolerance to drought stress than that adapted to the semiarid littoral climate,suggesting that tolerance in R.raetam is dependent on accumulation of osmolytes.
基金This work was supported by the Cadi Ayyad University and"Laboratoire Ecologie et Environnement(L2E)"an associated unit to the "Centre National de la Recherche Scientifique et Technologique(CNRST)"URAC32.
文摘Atlantic forest natural soil flora was tested on two leguminous pioneer species Acacia gummifera and Retama monosperma to be used in rehabilitation programs of the coastal sand dunes forest of the Essaouira region.The rhizospheric soil of two endemic plant species:R.nonosperma and Juniperus phoenicea was sampled and split into two categories,one from native rhizospheric soil,the other of the sterilized rhizospheric soil.Investigation was focused on mycorrhizal formations,but other forms of beneficial symbiosis such as rhizobia and viable soil microflora were also studied.Growth and nutrition variables assessed included lengths of roots and shoots,number of branches,ratio of root to shoot dry mass and water,nitrogen and phosphorus levels.Results showed important mycorrhizal associations in roots of both plants,presence of nodules and abundance of viable soil microflora.J.phoenicea had a 100%frequency of mycorrhizal formation and an intensity of 80%compared to a frequency of 80%and intensity of 54%for R.monosperma.Nodules had the same density of CFU regardless of the origin.Abundance of viable microflora in rhisospheric soil of R.monosperma,J.phoenicea and the control differed significantly.Among the studied variables for A.gummifera and R.monosperma,nitrogen and phosphorus uptakes significantly wit the use of the nonsterilized rhizospheric soil.Both species doubled their phosphorus uptake when colonized by mycorrhizal species,R.monosperma doubled its nitrogen uptake and A.gummifera increased it by seven times compared with the control.No significant difference was noted for the other variables.
