scholarly journals Ceratocystis fimbriata Employs a Unique Infection Strategy Targeting Peltate Glandular Trichomes of Sweetpotato (Ipomoea batatas) Plants

2020 ◽  
Vol 110 (12) ◽  
pp. 1923-1933
Author(s):  
Yong Sun ◽  
Mengqiu Li ◽  
Yansu Wang ◽  
Lianwei Li ◽  
Meng Wang ◽  
...  

The infection processes of Ceratocystis fimbriata BMPZ13 (BMPZ13) was elucidated on vegetative tissues of sweetpotato plants employing light and scanning electron microscopy. Vegetative tissues infected with C. fimbriata BMPZ13 by either wounding or nonwounding inoculation methods developed typical disease symptoms, establishing black rot in stems and necrosis on buds, young leaves, and stems of sprouts, in addition to wilt on leaves and shoot cuttings, typical of vascular associated diseases. The runner hyphae of C. fimbriata BMPZ13 formed from germinated conidia were able to directly penetrate the epidermal cuticle for initial infection and invade sweetpotato peltate glandular trichomes, specialized secretory structures to store and secrete metabolites. A two-step biotrophic phase was observed with nonwounding inoculation on leaves and stems, featuring both intercellular and intracellular invasive hyphae, with the latter found within living cells of the leaf epidermis. Subsequent to the biotrophic phase was a necrotrophic phase displaying cell death in infected leaves and veins. Additionally, this cell death was an iron-associated ferroptosis, supporting the notion that iron is involved in the necrotrophic phase of C. fimbriata BMPZ13 infection. Significantly, we establish that C. fimbriata employs a unique infection strategy: the targeting of peltate glandular trichomes. Collectively, our findings show that C. fimbriata is a plant fungal pathogen with a hemibiotrophic infection style in sweetpotato vegetative tissues.

2009 ◽  
Vol 62 ◽  
pp. 402-402
Author(s):  
S.L. Lewthwaite ◽  
P.J. Wright

The predominant diseases of the commercial kumara (Ipomoea batatas) or sweetpotato crop are caused by fungal pathogens The field disease pink rot results from infection by the fungus Sclerotinia sclerotiorum Lesions form on vines but may spread down stems to the roots The widespread nature of this disease in sweetpotato appears peculiar to New Zealand Scurf is a disease caused by Monilochaetes infuscans which occurs in the field but may proliferate amongst stored roots The disease causes a superficial discolouration of the root surface which is mainly cosmetic but can also increase root water loss in storage Infection by Ceratocystis fimbriata produces a disease known as black rot The disease can be transmitted amongst plants at propagation but is particularly rampant amongst roots in storage This disease is readily transmitted and can cause severe economic loss Fusarium oxysporum causes surface rots in stored roots characterised by light to dark brown lesions that tend to be firm dry and superficial The lesions may be circular and centred on wounds caused by insects or mechanical damage at harvest Soft rot caused by Rhizopus stolonifer generally occurs in roots after they are washed and prepared for the market Fungal infection occurs through wounds or bruised tissue producing distinctive tufts of white fungal strands and black spores


Plant Disease ◽  
2005 ◽  
Vol 89 (9) ◽  
pp. 1012-1012 ◽  
Author(s):  
L. Cardin ◽  
B. Delecolle ◽  
B. Moury

Dichondra repens (kidneyweed or ponysfoot), family Convolvulaceae, is a perennial plant with persistent leaves and is grown alone or in association with turfgrass in subtropical and Mediterranean regions. Because of its prostrate growth habit, it does not need to be mowed. It is also used as a potted plant for house decoration. During surveys of lawns in public gardens of the Franco-Italian Riviera conducted from 1993 to 2003, we noticed 0.1- to 0.5-cm-diameter, brownish, necrotic spots on leaves of D. repens in Antibes, Cannes, Menton, Nice, and Vallauris (France) and in Arma di Taggia, Diano Marina, Imperia, La Mortola, Ospedaletti, San Remo, and Ventimiglia (Italy). Symptoms were more intense in the spring on young leaves but lesions remained all year on older leaves. Two species of fungal pathogens were frequently isolated from these spots. One fungus produced brown, erect conidiophores with brown, pear-shaped conidia and bifid, subhyaline beaks. Conidia formed singly, were composed of 8 to 10 cells with transverse and longitudinal crosswalls, and had one to four hyaline spurs frequently longer than the conidia. Conidia measured 90 to 260 × 16 to 29 μm. The pathogen, identified as Alternaria dichondrae (1), was previously characterized in Italy, New Zealand, and Argentina. The second fungus species produced clumps of erect, brown conidiophores with hyaline, filiform conidia composed of 10 to 20 cells. These conidia measured 90 to 310 × 3 to 3.5 μm. This fungus was identified as a Cercospora sp. (2), a genus not previously reported on D. repens. For both fungi, necrotic spots similar to those observed in natural infections were obtained after spraying a suspension of mycelium and conidia onto leaves of D. repens seedlings that had two to four expanded leaves that had been pricked with a pin. The plants were maintained under high humidity. Assays of mycelium growth on agar media containing various fungicides showed that 1 ppm of pyremethanil completely inhibited the growth of A. dichondrae, whereas a mixture of 10 ppm of diethofencarb and 10 ppm of carbendazine completely inhibited Cercospora sp. growth. Telia were also observed on the lower surface of D. repens leaves, sometimes in association with disease symptoms of A. dichondrae and Cercospora sp. Disease symptoms of the rust were yellowing and curling of the leaf surface with erect petiole, whereas healthy plants were prostrate with plane leaf surfaces. The two-celled teliospores had smooth cell walls, a single germinative pore per cell, and measured 32 to 34 × 12 to 13 μm with a thin unattached pedicel. This rust fungus was consequently classified in the genus Puccinia (2), also not previously reported as a pathogen of D. repens. It is possible that Poaceae plants such as Poa pratensis grown in association with D. repens were the inoculum source. Whereas A. dichondrae and Cercospora sp. do not induce severe diseases and are not widespread, the prevalence of Puccinia sp. tends to increase over time, requiring appropriate treatments to manage infected turf grasses. References: (1) P. Gambogi et al. Trans. Br. Mycol. Soc. 65:322, 1975. (2) G. Viennot-Bourgin. Les Champignons Parasites des Plantes Cultivées, Masson ed. Paris, 1949.


Author(s):  
Xiaoyu Su ◽  
Zhenbao Jia ◽  
Fei Tao ◽  
Jiamin Shen ◽  
Jingwen Xu ◽  
...  

Phytochemical-enriched edible greens, sweet potato leaves (Ipomoea batatas L.), have become popular due to potential health benefits. However, the phytochemical contents in sweet potato leaves and their subsequent change over harvest stages and growth condition are mostly unknown. In this study, the anthocyanin profile and content in leaves of four sweet potato cultivars, i.e., white-skinned and white-fleshed Bonita, red-skinned and orange-fleshed Beauregard, red-skinned and white-fleshed Murasaki and purple-skinned and purple-fleshed P40, were evaluated. Fourteen anthocyanins were isolated and identified by HPLC-MSI/MS. The most abundant was cyanidin 3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside, which comprised up to 20% of the total anthocyanins. Of the young leaves (1st and 2nd slip cuttings), Bonita contained the highest anthocyanin content followed by P40. Of the mature leaves (vine stage), Beauregard had the greatest anthocyanin (592.5 ± 86.4 mg/kg DW) and total phenolic (52.2 ± 3 mg GAE/g DW). It should be noted that the lowest anthocyanin and total phenolic content of shoots were found in P40, while tubers of P40 contain the highest content of each. Furthermore, the increase in leaf anthocyanin content over the growth stages that was observed in three of the cultivars but not in P40. No significant difference of anthocyanin content was found in Beauregard leaves grown in the high tunnels when compared with that in the open field. This study demonstrated for the first time that anthocyanin levels were significantly changed in response to various growth stages but not high tunnel condition, indicating that the effect of anthocyanin biosynthesis in sweet potato leaves is highly variable and genotype specific.


2015 ◽  
Vol 87 (2) ◽  
pp. 797-812 ◽  
Author(s):  
Taiza M. Silva ◽  
Divina A.A. Vilhalva ◽  
Moemy G. Moraes ◽  
Rita de Cássia L. Figueiredo-Ribeiro

Among the compounds stored by plants, several functions are assigned to fructans, such as source of energy and protection against drought and extreme temperatures. In the present study we analyzed the anatomy and distribution of fructans in vegetative organs of Dimerostemma vestitum (Asteraceae), an endemic species from the Brazilian campos rupestres. D. vestitum has amphistomatic and pubescent leaves, with both glandular and non-glandular trichomes. In the basal aerial stem the medulla has two types of parenchyma, which differ from the apical portion. The xylopodium has mixed anatomical origin. Interestingly, although inulin-type fructans with high degree of polymerization were found in all analyzed organs except the leaves, the highest amount and maximum degree of polymerization were detected in the xylopodium. Inulin sphero-crystals were visualized under polarized light in the medulla and in the vascular tissues mainly in the central region of the xylopodium, which has abundant xylem parenchyma. Secretory structures accumulating several compounds but not inulin were identified within all the vegetative organs. The presence of these compounds, in addition to inulin, might be related to the strategies of plants to survive adverse conditions in a semi-arid region, affected seasonally by water restriction and frequently by fire.


1981 ◽  
Vol 20 (6) ◽  
pp. 1235-1239 ◽  
Author(s):  
Akira Takeuchi ◽  
Miyuki Yamaguchi ◽  
Ikuzo Uritani

2009 ◽  
Vol 4 (6) ◽  
pp. 1934578X0900400 ◽  
Author(s):  
Claudia Giuliani ◽  
Roberto Maria Pellegrino ◽  
Bruno Tirillini ◽  
Laura Maleci Bini

The essential oils from both leaves (L) and flowers (F) of Stachys germanica subsp. salviifolia (Ten.) Gams (Labiatae/Lamiaceae) from Italy were analyzed by GC-MS for the first time. The distribution, morphology and histochemistry of the different types of glandular trichomes present on the epidermal surface were also determined. Twenty-nine constituents, representing 89.4% of the total leaf oil, and forty-one compounds, forming 97.8% of the total flower oil, were identified. Germacrene D (39.4%), phytol (10.2%), β-bourbonene (3.5%) and β-ylangene (3.3%) were recognized as the main constituents of the leaf essential oil, while limonene (24.1%), β-pinene (18.7%), germacrene D (12.8%) and ( E)-nerolidol (6.6%) were the main compounds of the flower essential oil.


2020 ◽  
Vol 194 (1) ◽  
pp. 69-83
Author(s):  
João Pedro Silvério Pena Bento ◽  
Edna Scremin-Dias ◽  
Flávio Macedo Alves ◽  
Vidal De Freitas Mansano ◽  
Ângela Lúcia Bagnatori Sartori

Abstract Phylogenetic analyses of early-diverging Faboideae have indicated that genera previously positioned in distinct tribes are instead closely related, e.g. in the Amburaneae clade, and the relatively recent rearrangements of many genera into clades has hampered the identification of morphological synapomorphies for previously unrecognized clades. Our aims are to evaluate anatomical vegetative characters of leaflets attached to reproductive features in the Amburaneae clade, to identify new synapomorphies for the clade and subclades, to identify characters supporting intergeneric relationships and diagnostic characters for the genus and species and to provide information about the morphology and histochemistry of secretory structures. The study was based on the anatomy of the leaflet of 19 species of the Amburaneae clade. Papillae cells, the presence of vascular system units and hypodermis are shared features of Amburaneae. Anatomical characters of the leaflet can be diagnostic at the generic and specific levels in Amburaneae. Secretory structures found in the clade are secretory cavities, secretory channels, idioblasts, mucilaginous epidermal cells and glandular trichomes. The broader concept of Amburaneae is reinforced here by morphological and molecular data, with the identification of new synapomorphies. Our dataset supports the intergeneric relationships resolved by molecular data.


Author(s):  
Ana Carolina Bezerra ◽  
Luana da Silva Barbosa ◽  
José Flávio Cardoso Zuza ◽  
Agda Malany Forte de Oliveira ◽  
Camila Firmino de Azevedo

Aims: The objective of this study was to identify the structural characteristics of the shoots of Mentha x villosa Huds and also, identify the main structures responsible for the production of active principles. Methodology: The analyzes were performed with stems and leaves from adult and healthy plants, which presented a uniform morphological pattern. The materials selected for the anatomical analyzes were fixed in FAA for 24 hours and after this period conditioned in 70% alcohol. Cross-sections and paradermic sections were manually made with a cutting blade. For sections analysis, 1% sodium hypochlorite was used for discoloration and safranine 10% dye for tissue staining. Results: The leaf of Mentha x villosa Huds presents asymmetric mesophyll, formed by palisade and lacunar parenchyma, and uniseriate epidermis. The diacytic stomata are located on the abaxial surface of the leaves with different sizes, all having a substomatal chamber. On both sides of leaves, glandular trichomes were observed in great quantity. The leaf midrib is formed by a large vascular bundle, with xylem facing the adaxial surface and phloem facing the abaxial surface. The stem presents uniseriate epidermis and below it can be found one or two layers of colenchyma. The vascular bundle consists of four main xylem points, and externally to it is found the phloem, which gives the quadrangular shape to the stem. Mentha x villosa Huds has characteristics that are common to aromatic species of the Lamiaceae family, which makes its characterization and differentiation difficult, as for example, its secretory structures which do not have taxonomic importance for differentiation on this species, since they are similar in other species of the same family. Conclusion: However, Mentha x villosa has a larger number of cell layers in the lacunar parenchyma, which is an important characteristic for the differentiation of species.


Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 675-680 ◽  
Author(s):  
Y. Ichihara ◽  
K. Fukuda ◽  
K. Suzuki

In order to clarify the mechanism of pine wilt caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus, nematode migration in tissues and disease symptoms in Pinus thunbergii seedlings were investigated. One-year-old seedlings were inoculated with different pathogenic isolates of PWN under two different temperatures. At an early stage of symptom development, a virulent isolate of PWN multiplied in both bark and xylem and was distributed in cortical resin canals, cortical tissue, and xylem resin canals at 30°C. Cell death and disease symptoms developed in both bark and xylem. The virulent isolate of PWN at 25°C and the avirulent isolate of PWN at 30°C were distributed mainly in cortical resin canals, but rarely in xylem resin canals and cortical tissue. Disease symptoms and cell death occurred in cortical resin canals and rarely occurred in other tissues. These results demonstrated that the virulent isolate of PWN at low temperature and avirulent nematodes could not easily migrate to xylem resin canals and cortical tissue. It was shown that cell death and early symptom development coincided with PWN migration and, therefore, PWN invasion induces cell death and early symptom development.


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