Host–parasite interfaces in a resistant and a susceptible cultivar of Solanum tuberosum inoculated with Phytophthora infestans: tuber tissue

1976 ◽  
Vol 54 (9) ◽  
pp. 900-912 ◽  
Author(s):  
Hans R. Hohl ◽  
Peter Stössel

Host–parasite interfaces in potato tubers (Solanum tuberosum) of a resistant (Eba) and a susceptible (Bintje) cultivar inoculated with Phytophthora infestans were studied with transmission electron microscopy. In the resistant host the fungal haustoria are typically small and surrounded by an electron-dense extrahaustorial matrix and electron-transparent wall appositions, normally in form of complete encasements. Wall appositions are generally lacking in the susceptible host or occasionally are found as a collar at the base of the rather large haustorium, which is surround by a well developed extrahaustorial matrix. Since wall appositions probably contain largely a callose-like material, potential roles of fungal glucanases in this host–parasite system are discussed.

1976 ◽  
Vol 54 (16) ◽  
pp. 1956-1970 ◽  
Author(s):  
Hans R. Hohl ◽  
Elisabeth Suter

Host–parasite interfaces in leaves from a resistant (Eba) and a susceptible (Bintje) potato cultivar inoculated with Phytophthora infestans were studied using light and electron microscopy. Host penetration occurs similarly in both cultivars either through stomata or directly through the epidermis. In the susceptible host the fungus spreads throughout the tissue intercellularly and transcellularly, whereas in the resistant host it remains confined to the focus of infection. Yet in both cases live, normal-appearing hyphae can be observed even after 5 days. The appearance of haustoria in both cultivars is similar: they are either surrounded by an extrahaustorial matrix alone or in combination with wall appositions (collars or encasements). Structures with cytological features between those of haustoria and transcellular hyphae were also recorded, indicating a variety of host–parasite interactions within leaf tissue. Sporulation has been observed on the susceptible cultivar but not on the resistant one. The results suggest that cellular reactions against the intruding fungal hypha are qualitatively similar in both cultivars but that at the tissue level the intercellular spread of the pathogen and its sporulation are prevented in the resistant host but not in the susceptible host.


1992 ◽  
Vol 70 (6) ◽  
pp. 1228-1233 ◽  
Author(s):  
James P. Braselton

Sporogenic (cystogenous) stages of development of Spongospora subterranea (Wallroth) Lagerheim f.sp. subterranea Tomlinson infecting potato tubers were examined with transmission electron microscopy. Volume of nuclei in transitional Plasmodia was 28.2 ± 8.3 μm3. Serial section analysis revealed 37 synaptonemal complexes, hence the haploid chromosome number was considered to be 37. Total length of synaptonemal complexes per nucleus was 74.6 ± 1.4 μm, with individual synaptonemal complexes ranging in length from 1.34 ± 0.07 μm to 3.48 ± 0.17 μm. No polycomplexes were observed in transitional nuclei. Electron-opaque thickenings of lateral elements occurred irregularly. Additional ultrastructural features of sporogenic plasmodia included end-to-end paired centrioles defining the poles of the nuclei and a host–parasite boundary of a single unit membrane. Key words: karyotype, Plasmodiophoromycetes, Spongospora, synaptonemal complex.


2001 ◽  
Vol 91 (6) ◽  
pp. 579-585 ◽  
Author(s):  
Aaron Levin ◽  
Alexander Baider ◽  
Evgenia Rubin ◽  
Ulrich Gisi ◽  
Yigal Cohen

The ability of Phytophthora infestans, the causal agent of potato and tomato late blight, to produce oospores in potato tuber tissue was studied in the field and under laboratory conditions. In 1998 and 2000 field experiments, the canopy of potato cvs. Alpha and Mondial, respectively, were coinoculated with A1 + A2 sporangia of the fungus, and the infected tubers collected at harvest were examined for the presence of oospores. In 1998, only 2 of 90 infected tubers had oospores, whereas none of the 90 tubers examined in 2000 had any oospores. In the latter experiment, infected tubers kept in storage up to 12 weeks after harvest had no oospores. Artificial co-inoculations of whole tubers with A1 + A2 sporangia resulted only rarely in the formation of oospores inside the tubers. Co-inoculations of potato tuber discs taken from dormant tubers 0 to 16 weeks after harvest failed to support any oospore production, whereas discs taken from sprouting tubers of ≥18 weeks after harvest allowed oospores to form. Tuber discs showed enhanced oospore formation when treated before inoculation with either sugars, amino acids, casein hydrolysate, β-sitosterol, or chloroethylphosphonic acid. In contrast, reducing airflow into the petri dishes where potato tuber discs were incubated reduced the number of oospores produced. The number of oospores produced in tuber tissue was lower compared with that in leaf tissue regardless of the origin of isolates used. The data show that the ability of Phytophthora infestans to produce oospores in potato tuber tissue is very limited and increases with tuber aging.


1975 ◽  
Vol 6 (3) ◽  
pp. 301-305 ◽  
Author(s):  
Robert M. Zacharius ◽  
Edwin B. Kalan ◽  
Stanley F. Osman ◽  
Samuel F. Herb

Author(s):  
E.O. Shmelkova ◽  
M.A. Slugina ◽  
A.A. Meleshin ◽  
E.V. Romanova

Работа посвящена разработке и тестированию универсальных праймеров для ПЦР-амплификации полноразмерных генов-ортологов β-фруктофуранозидазы (кислой вакуолярной инвертазы) у видов и сортов картофеля (Solanum tuberosum). Крахмал – основной источник энергии и резервный углевод, накапливающийся в амилопластах клубней. Образовавшаяся в результате фотосинтеза молекула глюкозы при реакции с фруктозой образует сахарозу – основную транспортную форму углеводов в растении. В клубни сахароза доставляется по флоэме (апопластный путь), где в межклеточном пространстве расщепляется до глюкозы и фруктозы, которые затем проникают в клетки паренхимы. Глюкоза служит в дальнейшем субстратом для синтеза крахмала в амилопластах. Однако при воздействии пониженных температур крахмал в клубнях картофеля разрушается до редуцирующих сахаров. Параллельно этому процессу идет ресинтез сахарозы до глюкозы и фруктозы за счет фермента кислой вакуолярной инвертазы (β-фруктофуранозидазы), кодируемой геном Pain-1. В совокупности эти процессы приводят к избыточному накоплению моносахаров в клубнях картофеля, так называемому холодовому осахариванию (cold-induced sweetening). При этом создаются условия для интенсивного образования меланоидинов, вызывающих потемнение мякоти картофеля, что значительно ухудшает товарное качество продукта. Таким образом, изучение гена Pain-1, кодирующего вакуолярную инвертазу, а именно, его идентификация и анализ структуры – важная задача, необходимая для поиска доноров, устойчивых к холодовому осахариванию. Первоочередная задача для этого – разработка и тестирование праймерных комбинаций, позволяющих амплифицировать полноразмерный ген у диких видов картофеля, а также сортов и линий культивируемого картофеля (S. tuberosum). В данной работе приведены результаты разработки и тестирования универсальных праймеров, с помощью которых можно амплифицировать как полноразмерные гены-ортологи, так и фрагменты гена Pain-1, а также подобраны оптимальные условия для проведения ПЦР реакции. Было разработано 6 праймерных комбинаций (PainF – PainR, PainF – Pain1exR, Pain1exF – Pain3exR, Pain2inF – Pain2inR, Pain3exF – Pain5exR, Pain5exF – PainR), среди которых комбинация PainF – PainR позволяла амплифицировать полноразмерный ген, остальные – внутренние и будут использованы в дальнейшем при секвенировании фрагментов исследуемого гена. Эти праймеры были успешно протестированы на 15 образцах, включающих представителей пяти дикорастущих видов картофеля (S. gourlay, S. chacoense, S. pinnatissectum, S. stoloniferum, S. vernei) и десяти сортов российской и зарубежной селекции (Гала, Ласунок, Ред Скарлетт, Рассет Бербанк, Мирас, Башкирский, Жуковский ранний, Матушка, Елизавета, Сударыня).The purpose of research is design and testing of universal primers for PCR amplification of full-length-fructofuranozidase orthologs genes (acid vacuolar invertase) in wild species and potato (Solanum tuberosum) varieties. Starch is the main source of energy and a reserve carbohydrate, that accumulates in tubers amyloplasts. Glucose molecule, produced by photosynthesis, reacts with fructose and forms sucrose, which is the main transport type of carbohydrates in the plant. In the tuber, sucrose is delivered via phloem (apoplast), where it splits into glucose and fructose, which then go to the parenchyma cells. Glucose is a further substrate for the starch synthesis in amyloplasts. However, low temperatures influence on potato tubers leads to starch break down to reducing sugars. In parallel to this process there is happens resynthesis of sucrose to glucose and fructose by acid vacuolar invertase enzyme (β-fructofuranosidase) encoded by Pain-1 gene. Together, these processes lead to an excessive accumulation of monosaccharides in potato tubers. This process also called as cold-induced sweetening. It creates conditions for the intensive formation of melanoidins, which cause a potato tubers darkening, which considerably impairs the commercial quality of the product. Thus, the study Pain-1 gene that encodes the vacuolar invertase (its identification and structure analysis) is an important task required for the search of donors resistant to cold-induced sweetening. The primary task for this is the design and testing of primer combinations that allow to amplify the full-length gene in wild potato species, varieties and lines of cultivated potato. In this work, we develop and test universal primers, that can amplify both full-length orthologs and fragments of the Pain-1 gene, and also select the optimal conditions for carrying out the PCR reaction. Summary. The purpose of research is design and testing of universal primers for PCR amplification of full-length-fructofuranozidase orthologs genes (acid vacuolar invertase) in wild species and potato (Solanum tuberosum) varieties. Starch is the main source of energy and a reserve carbohydrate, that accumulates in tubers amyloplasts. Glucose molecule, produced by photosynthesis, reacts with fructose and forms sucrose, which is the main transport type of carbohydrates in the plant. In the tuber, sucrose is delivered via phloem (apoplast), where it splits into glucose and fructose, which then go to the parenchyma cells. Glucose is a further substrate for the starch synthesis in amyloplasts. However, low temperatures influence on potato tubers leads to starch break down to reducing sugars. In parallel to this process there is happens resynthesis of sucrose to glucose and fructose by acid vacuolar invertase enzyme (β-fructofuranosidase) encoded by Pain-1 gene. Together, these processes lead to an excessive accumulation of monosaccharides in potato tubers. This process also called as cold-induced sweetening. It creates conditions for the intensive formation of melanoidins, which cause a potato tubers darkening, which considerably impairs the commercial quality of the product. Thus, the study Pain-1 gene that encodes the vacuolar invertase (its identification and structure analysis) is an important task required for the search of donors resistant to cold-induced sweetening. The primary task for this is the design and testing of primer combinations that allow to amplify the full-length gene in wild potato species, varieties and lines of cultivated potato. In this work, we develop and test universal primers, that can amplify both full-length orthologs and fragments of the Pain-1 gene, and also select the optimal conditions for carrying out the PCR reaction. In total 6 primer combinations were designed (PainF - PainR, PainF - Pain1exR, Pain1exF - Pain3exR, Pain2inF - Pain2inR, Pain3exF - Pain5exR, Pain5exF - PainR), where PainF - PainR primer combination allowed to amplify a full-sized gene, the rest are internal and will be used in the further fragments sequencing of the β-fructofuranosidase gene. These primers were successfully tested on 15 samples, including five wild species of potato (S. gourlay, S. chacoense, S. pinnatissectum, S. stoloniferum, S. vernei) and ten varieties of Russian and foreign breeding (Gala, Lasunok, Red Scarlet , Rasset Burbank, Miras, Bashkirsky, Zhukovsky ranniy, Matushka, Elizaveta, Sudaryna).


1981 ◽  
Vol 59 (2) ◽  
pp. 251-263 ◽  
Author(s):  
X. Mourichon ◽  
G. Sallé

An electron microscopic study was performed on haustoria of Phytophthora cactorum (L. et C.) Schroeter developed in tissues of two cultivars of apple fruits: a susceptible variety ('Golden delicious') and a resistant one ('Belle de Boskoop'). Ultrastructure of intercellular hyphae and some aspects of their penetration between contiguous host cells were described. A light dissolution of the host cell walls was observed. Ontogenic investigations indicated that in the susceptible host, the wall of the fungal haustoria was covered with a dense-stained extrahaustorial matrix. Its origin and its polysaccharide nature were demonstrated. On the other hand, the resistant host developed, immediately after the inoculation, a papilla which gave rise, later on, to a sheath enclosing adult haustoria. The role of these callosic structures in the phenomenon of resistance was discussed.


2017 ◽  
Vol 72 (6) ◽  
pp. 393-396
Author(s):  
Liangyan Liu ◽  
Jun Han ◽  
Yong Shen

AbstractTwo new defensive constituents, solatuberenol A (1) and 3-O-β-d-glucopyranosyl stigmasta-5(6),24(28)-diene (2), were isolated from the potato tubers (Solanum tuberosum) infected with late blight disease. Their structures were identified by extensive spectroscopic analysis, including HRMS, IR, UV, 1D/2D NMR, ECD and quantum chemical calculations. Compounds 1 and 2 showed moderate activity against Phytophthora infestans with mycelia-growth inhibition of 30.1% and 52.4%, respectively, at the concentration of 500 ppm.


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