Emerging phytopathogenMacrophomina phaseolina: biology, economic importance and current diagnostic trends

Abstract

Macrophomina phaseolina (Tassi) Goid. is an important phytopathogenic fungus, infecting a large number of plant species and surviving for up to 15 years in the soil as a saprophyte. Although considerable research related to the biology and ecology of Macrophomina has been conducted, it continues to cause huge economic losses in many crops. Research is needed to improve the identification and characterization of genetic variability within their epidemiological and pathological niches. Better understanding of the variability within the pathogen population for traits that influence fitness and soil survival will certainly lead to improved management strategies for Macrophomina. In this context, the present review discusses various biological aspects and distribution of M. phaseolina throughout the world and their importance to different plant species. Accurate identification of the fungus has been aided with the use of nucleic acid-based molecular techniques. The development of PCR-based methods for identification and detection of M. phaseolina are highly sensitive and specific. Early diagnosis and accurate detection of pathogens is an essential step in plant disease management as well as quarantine. The progress in the development of various molecular tools used for the detection, identification and characterization of Macrophomina isolates were also discussed.

Screening a variable germplasm collection of Cucumis melo L. for seedling resistance to Macrophomina phaseolina

“…After the phase out of methyl bromide, its control has become increasingly troublesome (Islam et al 2012;Kaur et al 2012;Chamorro et al 2015). The identification of sources of resistance to this fungus can facilitate the management of this emerging disease in melons.…”

“…It has been frequently employed to perform an easy assessment of isolate aggressiveness (Shekhar et al 2006). Phenotypic as well as genetic variation in the pathogen population, even from the same geographical region, has been documented, adding difficulties to the implementation of successful management strategies (Almeida et al 2003;Purkayastha et al 2006;Kaur et al 2012;Mahmoudi and Ghashghaie 2013;Almeida et al 2014). The use of highly aggressive isolates is recommended to optimize the results of screening assays (Mahmoudi and Ghashghaie 2013).…”

“…The identification of sources of resistance to this fungus can facilitate the management of this emerging disease in melons. Although evaluations in naturally infested soils are employed to confirm the resistance of the selected material, the variability among fields with different soil characteristics, non-uniform inoculum distribution and microflora, and the variability across locations and seasons with different weather and management patterns, make these tests unappropriated for routine screening assays (Nischwitz et al 2004;Roustaee et al 2011;Kaur et al 2012). Artificial inoculation methods that induce lesions similar to those produced under natural infections are used to avoid inconsistent results between field experiments.…”

“…For example, this and other methods, where inoculum is introduced into the plant by causing tissue wounding, can break down some stem resistance barriers, such us structural barriers, and increase disease severity (Hutcheson 1998;Kaur et al 2012). However, it has been used efficiently to screen for resistant sources by reducing field testing expenses and length of time for evaluations.…”

“…Macrophomina phaseolina is seed-borne and seed-to-seedling transmission has been documented (Kaur et al 2012). Generally this pathogen can cause a range of symptoms, such as seedling blight, pre and post-emergence damping-off, bleaching of stems, gum exuding from stems as the bleached areas turn drier, stem and root rot, leaf blight and death near the crown of the plant and wilting of the plant.…”