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Septoria tritici blotch (STB) caused by Zymoseptoria tritici is one of the most important wheat diseases in the world and causes significant annual damage to wheat crops around the globe. The use of resistant cultivars is the most effective method for the management of this disease. Recently, the use of acquired systemic induced resistance has been proposed to manage wheat leaf blotch. In this study, the effect of salicylic acid (SA) on the relative changes of PAL and PR2 gene expression was investigated using qPCR technique. The expressions of catalase, peroxidase, and ascorbate peroxidase enzymes were also assessed in a sensitive wheat cultivar. Controlled and contaminated plants were sampled and compared at 0, 12, 24, 48, 96, and 240 hours after inoculation. The results showed that treatment with salicylic acid significantly reduced the level of disease compared to control plants. Comparison of gene expression patterns also showed that the expression of both PAL and PR2 genes in control and SA pre-treated plants increased after fungal inoculation; however, their expression was significantly higher (2.6 and 1.3 folds respectively for PAL and PR2) in plants treated with salicylic acid than the control. Moreover, treatment with salicylic acid significantly affected the activity of all three enzymes. It can be concluded that the high response of PAL and PR2 genes to salicylic acid pre-treatment, as well as increased activity of peroxidase along with the reduced activity of catalase and ascorbate peroxidase enzymes indicate the effective role of SA in inducing wheat resistance against STB.

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Charcoal rot caused by Macrophomina phaseolina is an important disease of soybean throughout the world. To understand the spatial distribution of soybean charcoal rot incidence and M. phaseolina populations in Golestan Province, 172 soybean fields were surveyed for population density, in two successive years, and integrated with Geographic Information System (GIS). Each year, 60 fields were also surveyed for disease incidence. Propagule density was determined by assaying five 1-g subsamples of soil from each field using a size-selective sieving procedure. In the seasons of 2009-2010 and 2010-2011, disease incidence ranged from 0 to 97% and 3 to 91% with the highest in Gorgan and Aliabad, respectively. Total mean of disease incidence were 21.01 and 35.84 percent in the province. In the two sampling years, Sclerotia were recovered from 73.33 and 93.57% of the total fields. The average population density per gram of soil ranged from 0.65 to 14.31 and 4.7 to 16.9, respectively, with the highest levels in Aliabad in both years. Charcoal rot incidence was positively correlated with soil populations of M. phaseolina (r= 0.61 and r= 0.47, P= 0.01). Geostatistical analyses of the survey data showed that the influence range of propagule density and disease incidence was between 8,000 to 14,000 m. In general, no significant correlation could be found between soil factors and sclerotia numbers. But, higher average air temperatures and decreased precipitation may have a significant effect on disease intensity.