Regulation by Galacturonic Acid of Pectinolytic Enzyme Production by Sclerotinia sclerotiorum

1996 ◽  
Vol 33 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Laurence Fraissinet-Tachet ◽  
Michel Fevre
1972 ◽  
Vol 50 (8) ◽  
pp. 1743-1748 ◽  
Author(s):  
Douglas P. Maxwell ◽  
Paul H. Williams ◽  
Martha D. Maxwell

The possible functional role of vesicles and crystal-containing microbodies in the production of oxalate, endopolygalacturonase, or cellulase by Sclerotinia sclerotiorum was investigated. The presence of multivesicular bodies in hyphal tips was not correlated with secretion or production of oxalate or these extracellular hydrolases. More crystal-containing microbodies were present in hyphal tips grown on media which supported greater extracellular enzyme production. No correlation existed between numbers of crystal-containing microbodies in hyphal tips and production of oxalate. Numerous membrane-bound vesicles (0.09–0.18 µm diam) were associated with tips grown on a D-glucose–Na succinate medium which supported high production of oxalate. The general ultrastructural organization of these hyphal tips was similar to that reported for other ascomycetes. Differences in numbers and distributions of organelles were observed between hyphal tips and older hyphae as well as between hyphal tips grown on the different carbon sources.


2012 ◽  
Vol 58 (5) ◽  
pp. 605-616 ◽  
Author(s):  
Zafer Dallal Bashi ◽  
S. Roger Rimmer ◽  
George G. Khachatourians ◽  
Dwayne D. Hegedus

Sclerotinia sclerotiorum releases hydrolytic enzymes that sequentially degrade the plant cuticle, middle lamellae, and primary and secondary cell walls. The cuticle was found to be a barrier to S. sclerotiorum infection, as leaves stripped of epicuticular wax were more rapidly colonized. Consequently, the factors affecting the regulation of genes encoding polygalacturonase 1 (SsPG1) and a newly identified cutinase (SsCUTA) were examined. In vitro, SsCutA transcripts were detected within 1 h postinoculation of leaves, and expression was primarily governed by contact of mycelia with solid surfaces. Expression of SsPg1 was moderately induced by contact with solid surfaces including the leaf, and expression was restricted to the expanding margin of the lesion as the infection progressed. SsPg1 expression was induced by carbohydrate starvation but repressed by galacturonic acid. Glucose supported a basal level of SsPg1 expression but accentuated expression when provided to mycelia used to inoculate leaves. These observations were contrary to earlier reports indicating that glucose repressed SsPg1 expression while galacturonic acid induced expression. Pharmacological studies showed that disruption of calcium signalling affected SsCutA and SsPg1 expression and decreased S. sclerotiorum virulence, whereas elevated cAMP levels reduced virulence without affecting gene expression. The mechanisms involved in coordinating the expression of S. sclerotiorum hydrolytic enzymes throughout the various stages of the infection are discussed.


1969 ◽  
Vol 47 (6) ◽  
pp. 1007-1010 ◽  
Author(s):  
L. Van Den Berg ◽  
S. M. Yang

B. cinerea and S. sclerotiorum growing in a nutrient medium on the surface of carrots at 20 °C produced significantly more extracellular pectolytic enzymes when the carrots were exposed to 94–96% relative humidity than when exposed to 98–100% relative humidity. Tests in which these organisms were grown in a nutrient solution containing pectic substances showed that they produced pectolytic enzymes in significant quantities only when readily metabolizable sources of energy (e.g. ethanol, carbohydrates) were not available. These results suggest that the low relative humidity increased enzyme production by concentrating nutrients on the carrot surface to the point where they inhibited growth of the organisms and stimulated enzyme production. Tests also showed that pectolytic enzyme activity on the surface of unwashed carrots stored 9 months at 0–1 °C was substantially higher at 90–95% relative humidity than at 98–100% relative humidity. The results indicated that reduced decay at 98–100% relative humidity was largely due to lower pectolytic enzyme production.


2020 ◽  
Vol 145 ◽  
pp. 103482
Author(s):  
Wei Wei ◽  
Nickisha Pierre-Pierre ◽  
Hao Peng ◽  
Vishnutej Ellur ◽  
George J. Vandemark ◽  
...  

2010 ◽  
Vol 27 (4) ◽  
pp. 186-190 ◽  
Author(s):  
Araceli Marcela Ramos ◽  
Marcela Gally ◽  
María C. García ◽  
Laura Levin

2020 ◽  
pp. 16-19
Author(s):  
Е.В. Янченко

Цель исследований – дать оценку сохраняемости и болезнеустойчивости современных сортов и гибридов моркови столовой и определить корреляционные зависимости влияния биохимических показателей качества на сохраняемость и степень поражения моркови столовой различными видами болезней в процессе хранения. Исследования проводились в 2011–2016 годах во ВНИИО – филиале ФГБНУ ФНЦО по общепринятым методикам. В биохимической лаборатории отдела земледелия и агрохимии содержание сухого вещества определяли высушиванием до абсолютно сухого веса, общего сахара – по Бертрану, аскорбиновой кислоты – по Мурри, нитраты – ионоселективным методом. При характеристике моркови столовой важнейший показатель, определяющий его качество – количество сухого вещества и сахаров. В процессе хранения были выявлены следующие болезни моркови: серая гниль (Botrytis cinerea Pers. ex Fr.), белая гниль (Sclerotinia sclerotiorum (Lib.)), белая парша (Rhizoctonia carotae Rad.), альтернариоз (Alternaria radicina M., Dr. et E.). В большей степени сортообразцы моркови столовой поражались серой гнилью. Лучшими по сохраняемости сортообразцами были Корсар (94,6%), F1Берлин (94,5%), Берликум Роял (94,1%) и F1 Звезда (94%). Сохраняемость у зарубежных сортов и гибридов моркови столовой была немного выше, чем у отечественных (на 0,4%) как за счет меньшей величины убыли массы (6,3% против 6,4%), так и потерь от болезней (1,6% против 1,9%). Сохраняемость корнеплодов моркови находится в прямой корреляционной зависимости от содержания сухого вещества (r=+0,41), каротиноидов (r=+0,39), моносахаров (r­=+0,30) и суммы сахаров (r=+0,27). Проявление серой гнили находится в обратной корреляционной связи с содержанием сухого вещества и каротиноидов (r=-0,37 и r=-0,35 соответственно), белой парши – в прямой корреляции с содержанием сухого вещества , моносахаров и дисахаров (r= +0,21; r= +0,39; r= -0,41 соответственно), белой гнили в обратной корреляционной связи с содержанием сухого вещества, моносахаров и дисахаров. The purpose of the research is to assess the persistence and disease resistance of modern varieties and hybrids of carrots and to determine the correlation between the influence of biochemical quality indicators on the persistence and degree of damage to carrots by various types of diseases during storage. The research was conducted in 2011–2016 at ARRIVG – branch of FSBSI FSVC, according to generally accepted methods. In the biochemical laboratory of the Department of Agriculture and Agrochemistry, the dry matter content was determined by drying to absolutely dry weight, total sugar – by Bertran, ascorbic acid – by Murri, nitrates – by the ion-selective method. When describing carrots, the most important indicator that determines its quality is the amount of dry matter and sugars. During storage, the following diseases of carrots were detected: gray rot (Botrytis cinerea Pers. ex Fr.), white rot (Sclerotinia sclerotiorum (Lib.), white scab (Rhizoctonia carotae Rad.), alternariasis (Alternaria radicina M., Dr. et E.). To a greater extent, varieties of table carrots were affected by gray rot. The best preserved varieties were Corsar (94.6%), F1 Berlin (94.5%), Berlicum Royal (94.1%) and F1 Zvezda (94%). The persistence of foreign varieties and hybrids of table carrots was slightly higher than that of domestic ones by 0.4%. both due to a smaller amount of weight loss (6.3% vs. 6.4%) and losses from diseases (1.6% vs. 1.9%). The persistence of carrot root crops is directly correlated with the content of dry matter (r=+0.41), carotenoids (r=+0.39), monosaccharides (r=+0.30) and the amount of sugars (r=+0.27). The manifestation of gray rot is in inverse correlation with the content of dry matter and carotenoids (r=-0.37 and r=-0.35, respectively), white scab is in direct correlation with the content of dry matter (r= +0.21; r= +0.39; r= –0.41, respectively), white rot is in inverse correlation with the content of dry matter, monosaccharides and disaccharides.


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