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Rincón-Barón, Edgar Javier Gutierrez-Rodriguez, Ana Mariany Guerra-Sierra, Beatriz Elena Espinosa Matías, Silvia Microbiota 2022-05-06T14:43:29Z 2022-05-06T14:43:29Z 2020-02-13 0034-7744 https://repositorio.udes.edu.co/handle/001/6719 10.15517/RBT.V68I2.37340 2215-2075 Digital Histopathological alterations caused by Puccinia nakanishikii rust (Pucciniales: Pucciniaceae) in Cymbopogon citratus (Poaceae) plants. Introduction: Histopathological and histochemical aspects linked to the attack of fungal rusts to plants, as well as its relation with the different spore stages are topics rather scarce in the scientific literature. Objective: To describe and analyze the histopathological and histochemical aspects of Cymbopogon citratus and its relation with the different stages of the spores from the rust fungi Puccinia nakanishikii. Methods: During the months April and August 2013, leaves healthy and infected by Puccinia nakanishikii were collected in the Northwestern scarp of the Bucaramanga-Colombia plateau. The samples with injuries on diverse developmental stages were fixated and processed according to the standard protocols for embedding and sectioning in paraffin and resin. Sections obtained from paraffin (5-7 μm) were stained with Safranin-Alcian blue and Alcian blue-Hematoxylin. On the other hand, sections obtained from resin (0.5 μm) were stained with Toluidine blue. Further, freehand sections were obtained for an autofluorescence analysis. The observations and photographic record were done via photonic microscope and epifluorescence microscope. For the observations via scanning electron microscopy (SEM), the samples were fixated in Glutaraldehyde, dehydrated with 2,2 dimethoxypropane, then desiccated to critical point and finally coated with gold. Results:The leaves are generally hypostomatic, with long and short epidermic cell forming parallel rows and showing unicellular prickle trichomes and micro-trichomes. The abaxial surface is covered by epicuticular wax forming a dense layer. The adaxial epidermis is formed by groupings of bulliform cells and epidermal cells with rectangu-lar or squared contour. In the mesophyll, there is no differentiation between palisade and spongy parenchyma, its anatomy reflects the C4 metabolism. The formation of uredosori and teliosori both hypophyllous was observed. Urediniospores are the reinfecting agents phase, they have 4-5 equatorial germ pores and echinulate wall. Teliospores have smooth wall and a persistent pedicel. The urediniospores form a germ tube, generally on the abaxial leaf surface, these tubes develop towards the stomata reaching the mesophyll interior. No appressorium were observed. The epidermis limiting the uredosorus detaches due the development and pressure that exert both the urediniospores and capitate paraphyses. As the infection progresses, autofluorescense of the chloro-phyll is lost and the cells undergo necrotic processes. Afterwards, the phloem collapses and the xylem becomes slightly disorganized. At this moment, the infection is extended along the whole leaf blade, resulting in the leaf death and the plant defoliation. On advanced stages of the infection, the uredosori showed pycnidia, probably belonging to the hyperparasite Sphaerellopsis, these structures were closely associated to the rust infected tissues. Conclusions:Puccinia nakanishikii develops on the leaves of Cymbopogon citratus producing uredosori and teliosori. Urediniospores are the reinfective stage, teliospores were only observed at late stages of the infection. The epidermis and photosynthetic tissue are severely affected by cell necrosis. The vascular tissues are deeply affected on the advances stages of the infection. Ciencias Exactas y Naturales, Biotecnología Agroambiente y Salud 22 p application/pdf spa © Los Autores, 2020 https://creativecommons.org/licenses/by-nc/4.0/ info:eu-repo/semantics/openAccess Atribución-NoComercial 4.0 Internacional (CC BY-NC 4.0) https://revistas.ucr.ac.cr/index.php/rbt/article/view/37340/41432 Alteraciones histopatológicas causadas por la roya puccinia nakanishikii (Pucciniales: pucciniaceae) en plantas de cymbopogon citratus (poaceae) Histopathological alterations caused by Puccinia nakanishikii rust (Pucciniales: Pucciniaceae) in Cymbopogon citratus (Poaceae) plants Artículo de revista http://purl.org/coar/resource_type/c_6501 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Text http://purl.org/redcol/resource_type/ART Histopathology alterations Rust fungi Teliospores Ultrastructure Urediniospores Costa Rica 382 2 361 68 Rincón Barón, E., Gutiérrez Rodríguez, A., Guerra Sierra, B., & Matías, S. (2020). Histopathological alterations caused by Puccinia nakanishikii rust (Pucciniales: Pucciniaceae) in Cymbopogon citratus (Poaceae) plants. Revista De Biología Tropical, 68(2), 361-382. https://doi.org/10.15517/rbt.v68i2.37340 Scopus Revista de Biología Tropical Todas las Audiencias http://purl.org/coar/access_right/c_abf2 http://purl.org/coar/version/c_970fb48d4fbd8a85 Publicationopen.access