Pycnidial Stage Research Articles

Bacillus valezensis: A New Plant Growth Promoting Rhizobacterium for Plant Growth Promotion and Inhibition of Rhizoctonia bataticola for the Management of Dry Root Rot of Chickpea

Background: Chickpea production is threatened by dry root rot disease in recent years. The disease is caused by soil borne fungus Rhizoctonia bataticola (Taub) Butler with its pycnidial stage Macrophomina phaseolina (Tassi) Goid. Bacillus spp. is a rod shaped and gram negative rhizobacterium which is predominant in the soil. Hence, considering the economic importance of disease, the present investigation was carried out to repress the pathogen by using indigenous Bacillus spp. strains related to antagonistic potential and plant growth promoting traits Methods: Thirty indigenous bacterial PGPR strains were isolated from healthy rhizospheric soil samples of chickpea and their antagonistic potential was studied. Later, the potential ones were examined for plant growth promoting traits. The promising strains were identified at molecular level 16S rDNA. Results: All thirty PGPR strains of rhizospharic Bacillus were potentiality antagonistic against R. bataticola and nine strains showed more than 50 per cent inhibition of the pathogen. Out of nine strains, four strains recorded more growth promoting traits and they were identified at molecular level as Bacillus cereus, Bacillus velezensis, Bacillus subtilis and Bacillus subtilis sub sp. Subtilis. Bacillus valezensis is a new report on rhizosphaeric PGPR against R. bataticola in chickpea.

Особливості біології гриба Phomopsis helianthi М. та патогенезу фомопсису соняшника

One of the main issues of successful annual sunflower growing is resistance against the necrothrophic fungus Phomopsis helianthi Munt, which is capable to destroy the entire crop of sunflower. The aim of research was studying cycle of development fungus Phomopsis helianthi M. and the features of sunflower plants defeat. The investigations were carried out in the field in Genicheskiy district of Kherson region and in Kherson regional phytosanitary laboratory. In a long period of time, the disease is in latent form in seed. The first symptoms is pycnidia and clarification of affected seminal skin tissue appear during seeds germination. On the seeds of P. helianthi was discovered complete mushroom stage Diaporthe helianthi Munt Cv, et al. The obtained results indicate possibility of transmitting the disease by seminal material in other regions where this disease is absent. The stage of the D. helianthi mushroom in the teleomorph form in the field, we found at the end of May on stems of sunflower, which were wintered after harvesting. On the remains of plants, where pycnides of the phomaxis pathogen were formed, we commit the formation of the D. helianthi strain with 1-5 peritheces. The departure of ascospore began in the beginning of second decade of May. In third decade of June, a mass exit from the ascospores of peritations was noted. The first symptoms of illness on sunflower plants in Henichesk district of Kherson region were recorded at the beginning of second decade of July in 10 days after irrigation. On the stems of sunflower between 4-7 pairs of leaves formed dark gray stains. Over time, necrosis extends along the length of stem from the place of its initial manifestation. The stains size affected by pathogen stalks ranged from 2.5-3 cmto 12.7-14.0 cm. On affected by phomopsis plants of sunflower, disease pathogens formed a flattened ellipsoid-shaped pycnidia with an aperture. They were located dotted along the leading vessels and were characterized by the following sizes: 290-520 × 265-410 microns. In the ripening phase, pycnides were seen on surface side of stem. During rain or irrigation, they broke through stem epidermis and on its surface in form of strips out a mass of pycnospores. Thus, after latent pathogenesis phase, the pathogen actively begins to form a pycnidial stage. During sunflower growing season, the pathogenesis of phomopsis occurs in all overground organs of plants. The presence of Diaporthe helianthi strain with peritheces and ascospores on seed has been established, indicating possibility of spreading the disease with seeds. The latter are found on unprotected plant remains. During vegetation, pathogen forms an anamorphic stage, and teleomorphic in the end. Phomopsis helianthi causes damage to overground part of sunflower plants in form of necrotic stains, damage to stem tissue, loss of turgor, burns of leaves and under-harvest. Key words: annual sunflower, Phomopsis helianthi M., Diaporthe helianthi Munt Cv, et al., biology of development, distribution.

Unravelling Effects of Temperature and Soil Moisture Stress Response on Development of Dry Root Rot [<i>Rhizoctonia bataticola</i> (Taub.)] Butler in Chickpea

Erratic rainfalls and rise in temperature have become more frequent under the changing scenario of climate particularly in semiarid tropics. As a consequence of it, a drastic shift of chickpea diseases have been recorded throughout the major chickpea growing regions in India and elsewhere. Dry root rot (DRR) caused by Rhizoctonia bataticola (Taub.) Butler [Pycnidial stage: Macrophomina phaseolina (Tassi) Goid] was found as a potentially emerging constraint to chickpea production than wilt (Fusarium oxysporum f. sp. ciceris). Increasing incidence of DRR indicate strong influence of climate change variables such as temperature and moisture on the development of disease. The present study therefore was conducted to quantify the role of temperature and soil moisture associated with infection, colonization and development of DRR under controlled environment. The DRR incidence was significantly affected by high temperature and soil moisture deficit. Out of five temperature regimes (15?C, 20?C, 25?C, 30?C and 35?C) and four moisture levels (40%, 60%, 80% and 100%), a combination of high temperature (35?C) and soil moisture content (60%) predisposes chickpea to DRR. The study clearly demonstrates that high temperature coupled with soil moisture deficit is the climate change variables predisposing chickpea to R. bataticola infection, colonization and development.

Molecular and morphological diversity in Rhizoctonia bataticola isolates causing dry root rot of chickpea (Cicer arietinum L.) in India

Dry root rot caused by Rhizoctonia bataticola (Taub.) Butler. [Pycnidial stage: Macrophomina phaseolina (Tassi) Goid] is emerging as a serious biotic constraint for chickpea production. To find out the diversity in R. bataticola populations in India, a total of 94 isolates collected from R. bataticola infected chickpea plants from different agro climatic regions of India were analyzed with amplified fragment length polymorphism (AFLP) and different morphological properties. R. bataticola populations collected from different agro-ecological zones were very diverse in respect to their different cultural and morphological parameters like colony color, growth pattern, growth rate, mycelial characters, sclerotial initiation time, sclerotial intensity and morphology of the sclerotia. Five AFLP primer combinations provided a total 121 fragments. All fragments were found polymorphic with an average polymorphic information content value of 0.213. The dendrogram based on AFLP analysis showed that the maximum number of R. bataticola isolates were very diverse and did not depend on geographical origin. Both morphological and molecular data correlated each other and supported that the R. bataticola present in India were diverse and independent to their origin.

Gremmeniella abietina (Lagerb.) Morelet: Distribution in Serbia and Montenegro, significance and control

Fungus G. abietina is one of the most dangerous pathogenic fungi occurring in conifer plantations and Pinus species are especially at risk. Among pines, the most susceptible species is Austrian pine, and particularly endangered plantations are between 8 and 25 years of age. This fungus was found in Serbia and Montenegro on Austrian pine, Scots pine and spruce, but it was only in mountainous regions (Kopaonik, Vlasina, Goc, Durmitor). G. abietina forms both stages (anamorph and teleomorph) in its development. The imperfect form is far more significant for the infection process, i.e. the pycnidial stage and generally all infections are caused by conidia (pycnospores). Apothecia will be formed on the bark only two years after tree dying. In the severely infected plantations, all dead trees should be felled and removed, and the remaining trees should be treated with copper fungicides.

Sources of infection and methods of control of Septoria oenotheraein evening primrose (Oenotheraspp.)

Septoria oenotheraeWest. can cause severe damage in overwintered crops of evening primrose (Oenothera spp.), including complete crop loss. Damage would be reduced if the sources of infection could be identified and removed. Examination of seed capsules inoculated with S. oenotheraeshowed that 96% of the pycnidia present were on the outside of the capsules, and seeds bearing pycnidia were only rarely found. However, internal infection of seeds from these capsules was demonstrated by both a blotter test and by culturing on agar media. Immersing seeds in 45°C water for 25 minutes destroyed viable fungal propagules located internally in seeds without reducing seed germination. The pathogen was also shown to overwinter in the pycnidial stage on stems left standing in the field. It is concluded that both internal seed-borne infection and overwintered crop debris are potential sources of infection in commercial seed stocks of evening primrose.

Gremmeniella abietina (lagerb) morelet: Distribution in Yugoslavia, significance and control

Fungus G. abietina is one of the most dangerous pathogenic fungi inhabiting conifer plantations, and especially endangered species are the pines. Among the pines, the most susceptible species is Austrian pine, and endangered plantations are aged between 8 and 25 years. This fungus was detected in Serbia and Montenegro only on the mountains (Kopaonik, Vlasina, Go?, Durmitor). The fungus was identified on Austrian pine, Scots pine and spruce. In its development G. abietina forms both stages (anamorph and teleomorph). Its imperfect form i.e. pycnidial stage, is far more significant for the infection process, and mainly all infection is carried by conidia (=pycnospores). Infection of trees is possible throughout the year, but the critical period of infection is May-June. Conidia are transmitted by raindrops, and the infection is spread through the buds and bark of young shoots. Incubation period lasts for 9 months, i.e. if infection occurs in June of the current year, the first visible symptoms of infection occur in March of the following year. The symptoms of infection are visible at the base of buds (cross section), on the needles (initial orange discolouration at the base of the needles, and then the whole needle turns brown and drops) and on the bark of young shoots. Soon after infection symptoms, the fruiting bodies (i.e. pycnidia) appear on the necrotic tissues of the host. Apothecia form on the bark two years after tree dying. In the severely infested plantations, all dead trees should be felled and removed, and the remaining trees should be treated with copper fungicides. As this is a quarantine disease, care must be taken to prevent the spread of the disease to the new uninfected regions. This measure is imposed by the legal regulations on quarantine diseases.

A modified ‘beeli formula’ as identification tool for asterinaceous fungi and their pycnidial stages

A modified ‘beeli formula’ as identification tool for asterinaceous fungi and their pycnidial stages

The Dictyochlamydospore of Peyronellaea Glomerata (Corda) Goidanich Ex Togliani Contrasted with the Dictyoporospore of Alternaria Tenuis Auct.

SUMMARYThe differences which exist between the dictyochlamydospore of Peyronellaea and the dictyoporospore of Alternaria are summarized as follows:1. The dictyochlamydospore of Peyronellaea is a non-deciduous spore fitting the general definition of a thallospore and more specifically that of a chlamydospore. When the elements in a spore chain break apart a ragged edge is left on each spore indicating the place of attachment to the previous spore.2. The dictyochlamydospore is composed of an outer wall which is separable from the walls of the component cells within the compound spore. The component cells of the dictyochlamydospore are rather easily separable from each other. Miniature pycnidia may occur between the elements in a dictyochlamydospore chain.3. The Alternaria spore is a deciduous spore and fits the definition of a conidium and porospore. When the elements in a spore chain break apart the only indication of attachment to the previous spore is by an almost imperceptible scar at the base and the beak of the spore.4. The Alternaria spore does not appear to be separable into an outer and an inner spore wall and the component cells of the dictyoporospore remain firmly united to one another. Pycnidia are not known to occur in the life cycle of any true Alternaria species.The genus Peyronellaea has been erected upon the presence of two spore forms present in the life cycle of its members. The pycnidial stage is ascribable to the genus Phoma, where it lies among many nondescript organisms of similar fructification. The chlamydosporic stage is distinct and easily recognizable.The term dictyospore is a general term lacking precision in respect to describing mode of spore origin and has been used erroneously to group together entirely different spore types. The dictyospores of Alternaria and Peyronellaea have been used as examples in demonstrating the superficial resemblance of dictyoporospores and dictyochlamydospores when contrasted with their mode of origin, structural difference, and manner of germination.

Studies on Puccinia polysora underw : III. Description and life cycle of P. polysora in West Africa

The form of P. polysora, the southern American maize rust, present in West Africa, is described. The apparent absence of aecidial and pycnidial stages and the failure of teleutospores to germinate when subjected to various chemical and physical stimuli suggest that the rust may be classified as a micro-cyclic, autoecious hemi-form.

A Previously Undescribed Fungus Causing a Leaf Spot of Bamboo

SUMMARYA fungus causing a leaf spot of a bamboo, Arthrostylidium racemiflorum Steud., is described. The pycnidial stage occurred abundantly on the material studied and has been designated as Ciliochorella bambusarum sp. nov. The ascocarpic stage is a hemisphaeriaceous fungus, placed in a new genus, Lateropeltis, a genus distinguished by having ascomata laterally attached to the stroma of the pycnidial stage. The ascogenous stage of this fungus is not known to occur except in conjunction with the pycnidial phase.

Guignardia Rhodorae, the Perfect Stage of Phyllosticta Maxima on Rhododendron

SUMMARYIn this study an ascigerous stage, originally described as Sphaerella (Laestadia) Rhodorae Cooke, is connected by means of pure culture methods with its pycnidial stage P. maxima Ellis & Ev. and its spermagonial stage P. Saccardoi Thüm. The characteristics of the perithecial stage are considered to be those of the genus Guignardia and the name G. Rhodorae (Cooke) comb. nov. is proposed. Synonyms are listed.P. maxima is considered a distinct species and not synonymous with P. Rhododendri West, as reported by Ellis and Everhart. It is also considered distinct from the fungus determined by Tengwall as P. maxima and reported by him as the imperfect stage of Venturia Rhododendri Teng.

Guignardia Rhodorae, The Perfect Stage of Phyllosticta Maxima on Rhododendron

During the last three years frequent collections of Rhododendron leaves from several New Jersey plantings have been examined for leaf-spotting fungi. Examinations early in the work revealed the common occurrence of two pycnidial forms both of which possess characteristics in common with those of the genus Phyllosticta. One of these has large, granular, ovoid to globose-elliptical spores, whereas the spores of the other are small and dumbbell-shaped. It became apparent very soon that these were often associated in the same or in similar lesions. Later a perithecial stage was found intermingled with both Phyllosticta forms. The association of these forms suggested that they were the pycnidial, spermagonial, and perithecial stages of the same fungus. Proof of this and the identity of these three stages are reported in this paper.

An Overwintering Pycnidial Stage of Cicinnobolus

A pycnidial stage of Cicinnobolus Cesatii has been found on dead clover and cucumber leaves, previously infected while living with powdery mildew and Cicinnobolus, and is apparently responsible for...

Parasitism of Rhizoctonia lamellifera, Small

IN the years preceding 1929, much controversy existed regarding the parasitism of the group of fungi known collectively as Rhizoctonia bataticola. The differences of opinion held by various sections of workers, and postulated principally by Small, Gadd and Briton-Jones, were largely attributable to the use of the one specific name bataticola for what now appears to be a relatively large group of sclerotium-forming fungi. Papers published by Ashby1 in 1927 and Haigh2 in 1930 showed that R. bataticola was a polymorphic fungus possessing a pycnidial stage, Macrophoma phaseoli, and was apparently distinct from two other forms which Haigh styled strain A and strain B. In 1933, I showed3 that strain A was physiologically and morphologically distinct from both strain B and M. phaseoli, and suggested that it should be designated by Small's original binomial R. lamellifera. The question of parasitism I did not touch upon.

LOPHIOSPHAERA (GLONIUM) VELATA, WITH A CRITICAL STUDY OF ITS SEPTONEMA MULTIPLEX STAGE

Despite recent investigations (Bisby, 1932; Lohman, I933), a number of species of hysteriaceous fungi, described as new in the earlier literature on the fungi of temperate North America, have not been studied critically either in regard to the accuracy of diagnoses and the validity of names or in regard to the probable affinities as shown by their imperfect stages. One such species, Glonium velatum., was described by Ellis and Everhart (I892) on specimens collected (Langlois) in Louisiana. This species, since then, has been reported only by Underwood and Earle (I897) for Alabama. That it is more widely distributed than the two records would indicate is shown by the present'report 2 which extends the range of the fungus to South Carolina, Florida, and Georgia.3 This report is concerned with the development of the fungus in culture and with the characteristics of its perithecial, pycnidial, and hyphomycetous stages. It presents certain necessary revisions in the description of the perithecial stage, the consideration of which has resulted in the inclusion of the fungus in the Lophiostomaceae rather than the Hysteriaceae. It records for the first time the features of the pycnidial stage and presents the evidence which reveals that the conidial development mentioned by Ellis and Everhart in their description and referred by them to Dendryphiumn is only another aspect of the fungus which they described and is the same as the Hyphomycete, Septonema multiplex B. & C. (Berkeley, 1874).

On the occurrence of phacidiella discolor (Mout. & Sacc.) potebnia in England

The occurrence of Phacidiella discolor (Mout. & Sacc.) Potebnia in England is recorded, associated with a die-back and canker of apple trees, as described in a recent paper on the pycnidial stage of this fungus by Southee and Brooks(i). The fungus also causes a black rot of apples in storage. Cultural work has shown that F. conspicua Marchal, and probably also “Pyrenochaeta furfuracea” (Fr.) Rostr., is identical with the pycnidial stage of Ph. discolor. Further information is given about the growth of the fungus on culture media. The synonomy of the fungus is considered.

Two Species of Physalospora on Citrus and Other Hosts

SummaryA species of Physalospora found on Citrus and other hosts in Cuba is described as Physalospora fusca. P. fusca is distinguished from other known species of the genus in having brown ascospores.The perfect stage of the fungus which has usually been called Diplodia natalensis in this country is apparently identical with Physalospora rhodina (Berk. & Curt.) Cooke.Physalospora gossypina as used in our earlier papers is apparently a synonym of P. rhodina.What is apparently the pycnidial stage of P. rhodina has been received from various localities outside the United States.

Botryosphaeria and Physalospora in the Eastern United States

SummaryBotryosphaeria Ribis is here reported from seventeen host species and Physalospora malorum from twenty-two host species in the eastern United States.Pycnospores have been produced in pure cultures from single ascospores from each of these hosts.Throughout this host range both species show remarkable uniformity in the size of their ascospores, the type of germination of the ascospores and in cultural characters on different media. Pycnospores, whether produced in culture or on the host, also show great uniformity.The size of the sporocarps in both species varies with the thickness and character of the host bark.The distinguishing characters of the two species, already pointed out in connection with our studies of these fungi on currant and apple, remain constant for all these hosts.Ascospores of Botryosphaeria Ribis are constantly smaller than those of Physalospora malorum. Ascospores of Botryosphaeria Ribis on germinating develop a short branched germ tube while those of Physalospora malorum develop a long unbranched germ tube. The pycnidial stage of Botryosphaeria is a Dothiorella while the pycnidial stage of Physalospora is a Sphaeropsis. Perithecia and pycnidia of Botryosphaeria generally occur in a stroma, while those of Physalospora have little, if any, surrounding stromatic tissues.

FUNGI ASSOCIATED WITH “DIE BACK” IN STONE FRUIT TREES. I.1

Summary. Diaporthe perniciosa, first isolated by Marchal from rots in stored fruits, has proved to be parasitic and one of the causes of “die back” in stone fruit trees. The various strains of D. perniciosa isolated from “die back” on peach and different varieties of plums have proved to be parasitic, morphologically identical, and cause definite wilt and “die back” on peach, plum, apricot and nectarine. Cross inoculations of the same organisms on two year old wood of Prince of Wales plum have so far not brought about typical symptoms of “die back,” but considerable disturbance, accompanied by gumming, has occurred at the points of inoculation. A strain obtained from apricot, which shows morphological differences, has also been proved to be capable of causing “die back” on peach and apricot. All the controls remained healthy. The progress of D. perniciosa in the host tissue is slow; infection occurs a considerable time, in some cases years, before any external symptoms appear. The mycelium permeates the internal tissues more especially the medullary rays, cortical tissues, phloem cambium, and vessels. D. perniciosa has a pycnidial or Phomopsis stage with “a” and “b” spores, and a perithecial or Valsa stage with numerous eight‐spored asci. The pycnospores emerge as whitish tendrils or globules through numerous lenticel‐like slits in the bark; the perithecial necks are long and protrude mostly through the same slits as the tendrils, and the ascospores are given off either through the ostiolum at the tip of the neck of the perithecium, or may burst through any part of the neck. The external symptoms are sunken areas and longitudinal slits in the bark; elongated strands of numerous lenticel‐like transverse slits through which tendrils and perithecial necks emerge; rapid wilt and browning of the trees in summer, or premature yellowing and fall of the leaves in the autumn. The internal tissues are discoloured and secondary thickening arrested. The pycnidial stage occurs on living or more or less moribund bark, the perithecial stage on the parts which are dead. D. perniciosa shows a certain degree of polymorphism on the host plant; on artificial media this polymorphism is much more marked. The Phomopsis stage of D. perniciosa grows and sporulates well on artificial media, but perithecia develop sparingly in cultures from pycnospores. Cultures of mass infections of ascospores of D. perniciosa have given rise in some cases to the Phomopsis stage with “a” and “b” spores; in others no “b” spores could be found. Mono‐ascospore cultures develop the pycnidial stage very sparingly, and no “b” spores have been observed in any of the cultures. Large numbers of perithecia develop in mono‐ascospore cultures on various media.