Cladosporium oxysporum on Prunus nepalensis in India

Abstract

Prunus nepalensis is grown as a fruit crop in Northeast India. Severe leaf blight was observed on almost 40% of seedlings grown in a polyhouse in Meghalaya, India. Light and scanning electron microscopy revealed the presence of Cladosporium oxysporum, which was confirmed by a pathogenicity test. To our knowledge this is the first report of leaf blight on P. nepalensis caused by C. oxysporum in India Keywords Cladosporium oxysporum . Prunus nepalensis Prunus nepalensis is an important fruit crop grown in Northeast India (Patel et al. 2008). Severe leaf blight symptoms were observed on 6-7 months old plants which were growing in a secondary nursery (polybags filled with 1:1:1 soil: sand: farm-yard manure) in a polyhouse at the Horticulture Research Farm of ICAR Research Complex for NEH Region, Umiam, Meghalaya, India. These seedlings were first grown in a primary nursery then moved to a secondary nursery after a month. In most cases, symptoms started at the leaf margins and extended towards the midrib. In the advanced stages of the disease whole leaves turned necrotic and heavy sporulation was evident on the lower surface of the leaves (Fig. 1). Sporulation was rarely seen on the upper leaf surfaces. The necrotic lesions were usually surrounded by a yellow halo (Fig. 2). Heavy defoliation of infected seedlings was also observed. Symptoms were more severe on immature leaves. Seedlings and grafted plants (rootstock-P. nepalensis) were housed in the same polyhouse and grafted plants appeared to be more susceptible. Voucher specimens were deposited in the herbarium collection of MACS Agharkar Research Institute, Pune and ICAR Research Complex for NEH Region, Meghalaya, India (AMH No. 9332, ICARHNEH 138).For pathogen isolation, leaf pieces taken at the edge of lesions with both infected and healthy portions were surface-sterilized using a 4% NaOCl solution for 30 seconds. The sections were washed twice in sterile distilled water and placed onto PDA amended with streptomycin (100 ppm). Four day old isolation cultures were subcultured on Synthetic Nutrient Agar (SNA) at room temperature (21±2°C) and diffused light conditions. Seven days old SNA cultures were used for morphological examination. Fungal structures produced on SNA were removed from the surface of the culture using a strip of Sellotape and mounted in 3% KOH for light microscopy (Correll et al. 1987). A dissecting microscope was used to select suitable areas for scanning electron microscopy (SEM) observations. Leaf areas with abundant sporulation were cut into 5 mm size and placed on double sided Sellotape. Using a JFC-1100 fine coat ion sputter device (JEOL, Tokyo, Japan), samples were sputter coated with gold. Gold-coated samples were then placed on aluminum stubs in a JEOL JSM 6360 scanning electron microscope (JEOL, Tokyo, Japan).For detailed microscopic observations, terms such as primary and secondary ramoconidia, intercalary and terminal conidia were used as described in . Conidiophores were macro-as well as micronematous, also branched in a fe...

Metagenomics Reveal Correlations Between Microbial Organisms in Soils and the Health of Populus euphratica

“…Trichoderma is a widespread fungus that is considered as an opportunistic avirulent plant symbiont (Harman et al, 2004;Bae et al, 2011). Previously, reports of Cladosporium oxysporum indicated that it has pathogenic effects on tomato and some vegetables, while it normally causes leaf spot (Wilingham et al, 2002;Baiswar et al, 2011;Zheng et al, 2014). Didymella glomerata is within the Didymellaceae family, which can cause stem lesions or cankers (Chen et al, 2015;Basim et al, 2016;Yao et al, 2016;Donati et al, 2018).…”

Modificaciones histológicas foliares causadas por organismos fúngicos en tres especies de Myrtaceae.

“…yBaiswar et al (2011) mencionan a Cladosporium oxysporum como un organismo saprófito y/o patógeno de plantas Bensaci et al (2015). utilizaron suspensiones de conidios de C. oxysporium, endófito aislado de tallos de Euphorbia bupleuroides subsp.…”