Hypomyces Solani Research Articles

Differential changes in the permeability of squash hypocotyl cells in relation to the severity of Hypomyces stem rot

Urea efflux was identical from excised squash hypocotyl tissues taken from healthy plants and fungus-free tissue adjacent to young lesions caused by Hypomyces solani f. sp. cucurbifae; rates of urea uptake were unaffected by the stage of lesion development. Electrolyte leakage from tissues above lesions was also unaffected during early stages of lesion formation. However, a decrease in permeability to cellular electrolytes occurred at the stage in lesion development when hypocotyls were girdled, but well before foliar chlorosis was evident. These results show that the stage of disease development is a critical factor in the expression of host cell permeability changes, and that squash hypocotyl cells are altered differentially in their passive permeability characteristics in response to infection by Hypomyces solani.

Observations on morphological and nutritional aspects of perithecial formation of Nectria haematococca and Hypomyces solani

Morphological and nutritional aspects of perithecial formation of Nectria haematococca Berk. & Br. and Hypomyces solani Rke. & Berth, were compared on a variety of media. Maximum perithecial development was observed on "natural" media. In synthetic liquid media, monosaccharides were more suitable for perithecial formation than were other carbon compounds examined. Likewise, amino acids as the sole source of nitrogen were found to be superior to either ammonium or nitrate nitrogen for perithecial production. Further, it was observed that, although light may be stimulatory, it was not an absolute requirement for perithecial induction. Isolates of these species showed remarkable uniformity in the morphology of perithecia, asci, and ascospores. Similarly, the identical response to carbon and nitrogen nutritional requirements for perithecial development substantiates a single identity for the isolates studied.

Characteristics of pectate lyase formation by Hypomyces solani f. sp. cucurbitae.

Pectate lyase, produced by Hypomyces (Fusarium) solani f. sp. cucurbitae, is considered a normal extracellular enzyme in that most of the enzyme was found in the culture medium during early stages of enzyme production and before extensive lysis. This enzyme was produced during active growth in the presence of citrus pectate but not citrus pectin. Enzyme yield was highest when the initial pH of the medium was between 5.5 and 7.5 and the temperature was between 25 and 29 C. Production of the enzyme was reduced when individual amino acids or inorganic N-sources were substituted for casein hydrolyzates. Glucose repressed enzyme formation when it exceeded 0.025%, while arabinose and xylose had little effect or stimulated greater production at 0.1%. Pectate lyase yield varied considerably, depending on fungus strain and inoculum level used. A delay in enzyme formation was reduced substantially when small amounts of agar were present in the liquid medium or the medium was solidified with agar.

Physiology of production of perithecia and microconidia in Hypomyces solani f. sp. Cucurbitae

Production of perithecial primordia or microconidia by Hypomyces solani f. sp. cucurbitae, race 1 was stimulated either by exposure of cultures to 4 °C, or by the addition of commercial tyrosinase to 10-day cultures growing in potato dextrose agar. These processes in H. solani f. sp. cucurbitae, race 2 and H. solani f. sp. pisi were not affected by either treatment. A strain of race 1, in which production of microconidia but not of perithecial primordia was increased by cold treatment was crossed with a strain with the converse response (primordia but not microconidia increased by cold). No recombinants for these character differences were found among 98 ascospores. It is concluded that a gene controlling cold stimulation exists as two alleles which determine the response. This gene showed no linkage to mating type. Active tyrosinase was produced in all race 1 strains after the cold treatment, while the race 2 strains showed no activity. H. solani f. sp. pisi had extracellular tyrosinase activity in cultures without cold treatment. These results suggest that tyrosinase can be a limiting factor in the initiation of reproductive morphogenesis.

Effect of Infection by Hypomyces solani f. sp. Cucurbitac on Apparent Free Space, Cell Membrane Permeability, and Respiration of Squash Hypocotyls

Initial symptoms and increases in respiration, apparent free space, and rate of leakage of amino acids occurred concomitantly in squash (Cucurbita maxima Dcne) hypocotyls infected by Hypomyces solani f. sp. cucurbitae Snyd. and Hans. Young, rapidly expanding lesions had greater respiratory rates and apparent free space than comparable tissues from healthy plants.Hypocotyl tissues above (1-45 mm) lesions possessed greater endogenous respiratory rates (2-3 times) and lower respiratory quotients than similar tissues from healthy plants. But no differences were found in membrane permeability to nonelectrolytes and water and in apparent free space between cells above lesions and healthy hypocotyls.Host cells contiguous to fungal hyphae at lesion margins were completely permeable to solutes and failed to accumulate neutral red or exhibit cyclosis.

The Cytogenetics of the Conidium in Microsporum gypseum and of Pleomorphism and the Dual Phenomenon in Fungi

SUMMARY The cytogenetics of the macroconidium was studied in wild-type and mutant strains of Nannizzia gypsea and N. incurvata, the two perfect states of Microsporum gypseum. One mutant (ng) arose spontaneously in N. gypsea as a result of chromosomal aberration, and the other (ni) in N. incurvata as a single gene mutation. The developing macroconidium of the wild type passes through three developmental stages: The first is marked by active nuclear division in a swollen hyphal tip that grows into a macroconidium. The second stage is marked by vacuolation and redistribution of the nuclei, due to the enlargement of the macroconidium. The third is a stage of septation, further enlargement and thickening of the wall. In the mutant ng, the macroconidium passes through the first stage with no noticeable variation. However, in the second and third stage variations occur. The nuclei are scattered and continue to divide, frequently forming chromatin threads, and septation often fails to occur or stops at the 2-3 septate condition. Occasionally, the macroconidia proliferate forming protuberances, long fine hyphae or secondary macroconidia. In the mutant ni, the macroconidia are highly distorted and their development is too irregular to describe. The cytogenetics of these so-called "pleomorphic" mutants was compared with that of the M-type mutants in Hypomyces solani f. cucurbitae, the perfect state of Fusarium solani. In the latter organism the macroconidium arises as a single uninucleate cell in which each nuclear division is followed by a septum formation and the resultant cells are always uninucleate. It is concluded that, regardless of growth pattern and nuclear condition, the M-type mutants resemble closely the "pleomorphs," and that mutation in the broad sense is the underlying mechanism of "pleomorphism" and the "dual phenomenon" in fungi. The last two terms, however, are inadequate and should be discarded. Although fungus variability is no longer a riddle to be solved, it is still a subject on which much attention is focused and a phenomenon described in various terms. Of the various terms coined, pleomorphism and the dual phenomenon deserve special attention. Pleomorphism is a type of

The Cytogenetics of the Conidium in Microsporum Gypseum and of Pleomorphism and the Dual Phenomenon in Fungi

SUMMARYThe cytogenetics of the macroconidium was studied in wild-type and mutant strains of Nannizzia gypsea and N. incurvata, the two perfect states of Microsporum gypseum. One mutant (ng) arose spontaneously in N. gypsea as a result of chromosomal aberration, and the other (ni) in N. incurvata as a single gene mutation. The developing macroconidium of the wild type passes through three developmental stages: The first is marked by active nuclear division in a swollen hyphal tip that grows into a macroconidium. The second stage is marked by vacuolation and redistribution of the nuclei, due to the enlargement of the macroconidium. The third is a stage of septation, further enlargement and thickening of the wall. In the mutant ng, the macroconidium passes through the first stage with no noticeable variation. However, in the second and third stage variations occur. The nuclei are scattered and continue to divide, frequently forming chromatin threads, and septation often fails to occur or stops at the 2–3 septate condition. Occasionally, the macroconidia proliferate forming protuberances, long fine hyphae or secondary macroconidia. In the mutant ni, the macroconidia are highly distorted and their development is too irregular to describe. The cytogenetics of these so-called “pleomorphic” mutants was compared with that of the M-type mutants in Hypomyces solani f. Cucurbitae, the perfect state of Fusarium solani. In the latter organism the macroconidium arises as a single uninucleate cell in which each nuclear division is followed by a septum formation and the resultant cells are always uninucleate. It is concluded that, regardless of growth pattern and nuclear condition, the M-type mutants resemble closely the “pleomorphs,” and that mutation in the broad sense is the underlying mechanism of “pleomorphism” and the “dual phenomenon” in fungi. The last two terms, however, are inadequate and should be discarded.

Calcium localization in Hypomyces-infected squash hypocotyls and effect of calcium on pectate lyase activity and tissue maceration

Pectate lyase from squash plants infected with Hypomyces solani f. sp. cucurbitae is dependent upon Ca for activity. As the Ca level is increased in reaction mixtures, the rate of degradation of pectate is increased. However, when the uronic acid/Ca ratio is [Formula: see text], enzymatic breakdown of pectate is inhibited. Pectate lyase activity is affected similarly when the pectate substrate is in a semisolid agar medium. Moreover, maceration of potato tissues is stimulated by a low exogenous supply of Ca but inhibited as the level is increased.Calcium is present in higher concentrations in lesions than adjacent healthy tissues, and autoradiography indicated that 45Ca accumulated in cell walls and middle lamellae in infected areas. However, calcium accumulation around lesions apparently does not greatly influence the rate of maceration by pectate lyase.

DIFFERENTIAL SENSITIVITY OF DIPHENYL-SENSITIVE AND DIPHENYL-TOLERANT STRAINS OF FUNGI TO CHLORINATED NITROBENZENES AND TO SOME DIPHENYL DERIVATIVES

In Hypomyces solani f. cucurbitae the inhibitory effect of diphenyl on spore germination, germ tube development, and subsequent growth was overcome by mutation to chloronitrobenzene tolerance at any of three previously known loci. Sectoring under the selective action of diphenyl similarly resulted in tolerance to chloronitrobenzenes. One mutant gene is sufficient to give the maximum diphenyl tolerance possible. Results of cross-tolerance tests with differentially sensitive strains of three other fungi showed the same relationship between diphenyl tolerance and chloronitrobenzene tolerance. Neither volatilities nor relative saturations were found to be of importance in an understanding of the reason for this relationship. Diphenyl-tolerant strains are also tolerant to compounds derived from diphenyl by simple substitutions. The magnitude of the tolerance may be influenced by the substituent, the position, and the fungus species.

Fusarium solani f. robiniae n. f., one of the causal fusaria of the twig blight of Robinia pseudoacacia

This paper deals with Fusarium solani f. robiniae n. f. [Hypomyces solani f. robiniae n. f.], one of the causal fusaria of the twig blight of Robinia pseudoacacia. This fungus was hermaphroditic and compatibility-heterothallic, and was independent from forms of F. solani in the mating relationship. However, the fertilization occurred between this fungus and F. solani derived from the decaying bark of Populus spp. suggesting that these two fungi are identical. According to the results of cross-inoculations between this fungus and various forms of Fusarium solani, this fungus was pathogenic to its own host, the twig of Robinia pseudoacacia, but not pathogenic to the squash seedling, the bean seedling, the pea seedling, the potato stem, the Morus twig and the Xanthoxylum twig, though mildly pathogenic to the potato tuber and the sweet potato sprout. On the other hand all the other forms of F. solani tested were not pathogenic to Robinia pseudoacacia. From these results the authors proposed a new form for this fungus as follows.Fusarium solani Mart. emend. Snyd. et Hans. f. robiniae Matuo et Sakurai n. f. [Hypomyces solani Rke. et Berth. emend. Snyd. et Hans. f. robiniae Matuo et Sakural n. f.] Hab. in vivis Robiniae pseudoacaciae, cetera ut in typo9).The type culture is deposited in Lab. Phytopath. & Mycol., Fac. Text. Sci., Shinshu Univ., Ueda, Japan, which was isolated from the twig of Robinia pseudoacacia suffered from blight disease.

GENETIC MARKERS AND LINKAGE RELATIONSHIPS FROM TETRAD DATA IN HYPOMYCES SOLANI f. CUCURBITAE

Ten loci were included in linkage studies with Hypomyces solani f. cucurbitae and the following linkage relationships were recognized: (1) compatibility locus (A/a) to a locus for tolerance to the chlorinated nitrobenzenes (cnb-2); (2) locus for femaleness (c) to the locus for maleness (m); and (3) locus for perithecial color (w) to a locus modifying femaleness (stp-4:). Usually parental ditype and tetratype asci were obtained from the cross ♂ × ♀ but the non-parental ditype ascus was found once. The two loci for sex appear to be separated by the centromere to which they both show close linkage. Centromere linkages have also been detected for the compatibility locus and the locus controlling perithecial color.

Taxonomy of the causal fungus of trunk-blight of Xanthoxylum piperitum and heterothallism in this fungus

The causal fungus of trunk-blight of Xanthoxylum piperitum (L.) DC., which was named Nectria elegans by Yamamoto and Maeda, was identified by the writers as Hypomyces solani (Rke. et Berth.) Snyd. et Hans. [Fusarium solani (Mart.) Snyd. et Hans.].Cross inoculations were carried out between this fungus and 7 forms and 2 races of Fusarium solani. This fungus was pathogenic only to Xanthoxylum piperitum and not to any host of the other forms of F. solani. On the other hand all the forms and races of F. solani tested were non pathogenic to Xanthoxylum piperitum. From these results, the writers propose the following nane for this fungus.Hypomyces solani (Rke. et Berth.) Snyd. et Hans. f. xanthoxyli Sakurai et Matuo nom. nov.[Fusarium solani (Mart.) Snyd. et Hans. F. xanthoxyli Sakurai et Matuo nom. nov.]Syn. Nectria elegans Yamamoto et MaedaHab. in vivis xanthoxyli, cetra ut in typo10)The type culture is deposited in Lab. Phytopath. & Mycol., Fac. Text. Seric., Shinshu Univ., Ueda, Japan, which was isolated from Xanthoxylum piperitum suffered from blight disease.The sexuality of this fungus was studied. The results of reciprocal spermatization among the monoascosporic strains proved that this fungus is hermaphroditic and shows the compatibility heterothallism. Interformic fertility between this fungus and f. cucurbitae, f. mori and f. radicicola race 2 of Hypomyces solani was tested. But the interformic cross did not occur in every occasion.

Nectria elegans Yamamoto et Maeda causing the trunk blight of Xanthoyxlum piperitum in comparison with Hypomyces solani Reinke et Berthold

The diagnosis of the trunk blight fungus of Xanthoxylum piperitum, Nectria elegans Yamamoto et Maeda, is as follows. Perithecia caespitose, superficial, astromate or hardly stromate, ovoid, apex papillate, minutely ostiolate, outer wall irregularly warted, brightly reddish orange to red, 180∼300μ diam., 280∼390μ heigh, perithecial wall 40∼50μ wide; asci clavate-cylindrical, apex obtuse or rounded, pedicellate, 8-spored, 80∼106×8∼11μ; ascospores ellipsoid, ends rounded, one-septate, smooth, hyaline, 9∼14×4.5∼6.5μ. Conidial stage, Fusarium elegans Yamamoto et Maeda, macroconidia on sporodochia falcate, slightly curved, apex subacute, pedicellate, 1-6-septate, mostly 3-5-septate, 16∼75×3∼5.5μ, mostly 29∼63×3.5∼5.5μ; microconidia in false heads, ellipsoid or subcylindrical, rarely slightly curved, continuous, rarely one-septate, hyaline, 6∼16×2.5∼5μ; chlamydospores terminal or intercalary, solitary or catenulate, 7∼11×5.5∼9.5μ; sclerotia sperse, globose to subglobose, cyano-black, 60∼125×50∼120μ.The diagnosis of the saprogenous fungus on rotting potatoes, Nectriopsis solani (Rke. et Berth.) Booth=Hypomyces solani Rke. et Berth., is as follows. Perithecia gregarious, globose to subglobose, with a conical beak fringed with a short collar of hyphal tips, dark red, smooth-walled, 270∼400μ diam., perithecial wall 30∼36μ wide; asci clavate, apex rounded, 8-spored, 80∼98×10∼12μ; ascospores ellipsoid, one-septate, verrucose, light brown, 14∼17×7∼10μ. Conidial stage, Fusarium cuneiforme Sherb., macroconidia fusoid, sometimes pedicellate, 3-septate, hyaline, 24∼35×5∼8μ; microconidia absent; chlamydospores terminal or intercalary, solitary or catenulate, globose, thick-walled, 10∼12μ diam.Nectria elegans Yamamoto et Maeda and Nectriopsis solani (Rke. et Berth.) Booth mentioned above are different from each other in morphological characteristic as well as parasitism, which indicates that they are distinct species. However, the former fungus was mistakenly identified by Sakurai and Matuo as Hypomyces solani Rke. et Berth. emend Snyder et Hansen, and also named erroneously Hypomyces solani f. xanthoxyli Sakurai et Matuo (Fusarium solani f. xanthoxyli Sakurai et Matuo) by its pathogenicity.

Is Nectria haematococca Berk, and Br. the perfect stage of Fusarium oxysporum Schl. forma pisi (Lindf.) S. and H.?

IN a recent communication1, Dr. E. W. Buxton reported the discovery of mature perithecia in a nutritionally deficient mutant isolate of Fusarium oxysporum Schl. forma pisi (Lindf.) S. and H. after ultra-violet irradiation. These perithecia were shown to be the perfect stage of this particular isolate and were identified as Nectria haematococca Berk. and Br. (= Hypomyces solani Rke. and Berth. emend. S. and H.).

On the form name and race of Hypomyces solani (Rke. et Berth.) Snyd. et Hans. which is pathogenic to the mulberry trees

The writers4, 5) reported in 1957 that Hypomyces solani (Rke. et Berth.) Snyd. et Hans.[Fusarium solani (Mart.) Snyd. et Hans.]was another causal fungus of Fusarium blight of mulberry trees, and the strains of this fungus, isolated from mulberry stems, were divided into two groups (α and β). In this paper the host ranges and the form names of the two groups are dealt with.The cross-inoculations were carried out among these fungi and 6 forms of F. solani, i. e. f. cucurbitae, f. eumartii, f. radicicola, f. phaseoli, f. pisi and f. batatas.The α group of the fungus was pathogenic on mulberry stems, but was non-pathogenic to squash seedlings, potato stems, potato tubers, bean seedlings, pea seedlings and sweet potato sprouts. On the other hand, the 6 forms of F. solani proved to be non-pathogenic on mulberry stems though they were severely parasitic on their own hosts. From these results, the writers propose the following name for the α group of the fungus.Hypomyces solani (Rke. et Berth.) Snyd. et Hans. f. mori Sakurai et Matuo, nom. nov.[Fusarium solani (Mart.) Snyd. et Hans. f. mori Sakurai et Matuo, nom. nov.]Hab. in vivis Mori, cetra ut in typo7).The β group of the fungus was pathogenic not only on mulberry stems (less virulent than α group) but also to pea seedlings and sweet potato sprouts and most vigorously to potato tubers. So the writers designate the β group Hypomyces solani (Rke. et Berth.) Snyd. et Hans. f. radicicola race 2[Fusarium solani (Mart.) Snyd. et Hans. f. radicicola race 2], and call the former f. radicicola, which causes the dry rot of potato tubers and is non-pathogenic on mulberry trees, F. solani (Mart.) Snyd. et Hans. f. radicicola race 1.The type cultures are deposited in Fac. Tex. Seric., Shinshu Univ., Ueda, Japan, which were isolated from mulberry trees suffered from the blight disease.

THE TAXONOMY AND HABITATS OF THE FUSARIUM SPECIES IN TRINIDAD, B.W.I.

A taxonomic study was made of isolates of Fusarium obtained by the writer from various habitats in Trinidad, B.W.I., during the early months of 1955. Initial phases of this study were carried out at the Imperial College of Tropical Agriculture, Trinidad, while the later phases were completed at the Plant Pathology Laboratory, Winnipeg, Man. Isolates of Fusarium were obtained from a total of 41 different species and botanical varieties of host plants, from scale insects, and from soil. A total of 11 species and two varieties of Fusarium, classified in 10 sections of the genus, were identified among the various isolates. These sections, species, and varieties are: section Macroconia, F. coccophilum (Desm.) Wr. & Rg.; Spicarioides, F. decemcellulare Brick; Pseudomicrocera, F. coccidicola P. Henn.; Arachnites, F. larvarum Fuckel; Arthrosporiella, F. semitectum Berk. & Rav.; Gibbosum, F. equiseti (Cda.) Sacc.; Lateritium, F. lateritium Nees, F. stilboides Wr.; Liseola, F. moniliforme Sheld., F. moniliforme var. anthophilum (A. Br.) Wr., F. moniliforme var. subglutinans Wr. & Rg.; Elegans, F. oxysporum Schlecht. emend. Snyder & Hansen; Martiella, F. solani (Mart.) App. & Wr. emend. Snyder & Hansen. Six of these species are reported for the first time to occur in Trinidad, namely, F. coccophilum, F. decemcellulare, F. larvarum, F. equiseti, F. stilboides, and F. solani. Fusarium semitectum and F. moniliforme were most frequently encountered.The ascomycetous or perfect state of F. coccophilum, Nectria ecoccophila Wr.; of F. decemcellulare, Calonectria rigidiuscula (Berk. & Brme.) Sacc.; of F. moniliforme, Gibberella fujikuroi (Saw.) Wr.; and of F. solani, Hypomyces solani (Rke. & Berth.) emend. Snyder & Hansen were collected in nature.This paper is illustrated with drawings of the majority of the Fusarium species and the ascomycetous states mentioned.

Variability and Perithecium Production in a Homothallic Form of the Fungus, Hypomyces solani

Variability and Perithecium Production in a Homothallic Form of the Fungus, Hypomyces solani

The Dual Phenomenon and Sex in Hypomyces solani F. curcurbitae

American Journal of BotanyVolume 30, Issue 6 p. 419-422 Article THE DUAL PHENOMENON AND SEX IN HYPOMYCES SOLANI F. CURCURBITAE H. N. Hansen, H. N. Hansen Division of Plant Pathology, University of California, Berkeley, CaliforniaSearch for more papers by this authorW. C. Snyder, W. C. Snyder Division of Plant Pathology, University of California, Berkeley, CaliforniaSearch for more papers by this author H. N. Hansen, H. N. Hansen Division of Plant Pathology, University of California, Berkeley, CaliforniaSearch for more papers by this authorW. C. Snyder, W. C. Snyder Division of Plant Pathology, University of California, Berkeley, CaliforniaSearch for more papers by this author First published: 01 June 1943 https://doi.org/10.1002/j.1537-2197.1943.tb14781.xCitations: 35AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume30, Issue6June 1943Pages 419-422 RelatedInformation

THE DUAL PHENOMENON AND SEX IN HYPOMYCES SOLANI F. CURCURBITAE

THE DUAL PHENOMENON AND SEX IN HYPOMYCES SOLANI F. CURCURBITAE