Resumo

FIERRO-CORRALES, Dagoberto et al. Morphological characterization and histopathology of Peronospora ciceris in chickpea (Cicer arietinum L.) leaves and seeds. Rev. Chapingo Ser.Hortic [online]. 2015, vol.21, n.1, pp.81-92. ISSN 2007-4034.  https://doi.org/10.5154/r.rchsh.2014.02.010.

Chickpea downy mildew is one of the most destructive diseases found sporadically in chickpea fields in the counties of Salvador Alvarado and Guasave, Sinaloa, Mexico. The aims of this study were to morphologically characterize the species of Peronospora causing downy mildew in chickpea, and to describe the histological changes induced by the pathogen in chickpea seeds and leaflets at different stages of infection (initial, intermediate and advanced). Samples of healthy and naturally-infected chickpea cv. "Blanco Sinaloa-92" leaflets and seeds were collected for morphological characterization of the pathogen and histological analysis. Cross-sections of leaflets and seeds were obtained with a manual rotary microtome and processed using the safranin-fast green differential staining technique. Morphological characterization indicated that Peronospora ciceris is the causative species of downy mildew symptoms in Sinaloa, Mexico. Histological evidence in leaflets with initial stages of infection showed palisade parenchyma with cell disruption, followed by hypertrophy and rupturing of cells. In addition, abundant coenocytic mycelial growth colonizing the vascular system and causing rupturing of the xylem vessels and phloem sieve tubes was observed. In leaflets with intermediate symptoms, the presence of intercellular mycelium, chloroplast degradation and loss of cell nuclei was detected. Leaflets with advanced symptoms exhibited damage in all tissues, showing massive cell destruction caused by extensive mycelial colonization in the epidermis, mesophyll, phloem and xylem. In seeds, intercellular mycelium was only observed in the embryonic cells.

Palavras-chave : Downy mildew; oomycete; severity.

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