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
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
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.
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.
