Effect of Submerging Solanum lycopersicum Roots inSalicylic Acid (SA) Solution for Different Durations onNematode Infection and Expressions of SlPR5 Gene

Abstract

Salicylic acid (SA) stimulates the mechanism of the plant defence and involvesin a role in plant pathogen interactions. Plant parasitic nematodes areimportant biotic stresses causing negative effect on plant growth anddevelopment. Treatment of plant roots with SA may increase the plant defencemechanisms against biotic stresses. However, the treated effect of SA on plantdefence mechanisms against a root-knot nematode, Meloidogyne incognita,has not been fully understood in terms of plant pathogen interactions.Therefore, this study was aimed to determine the most effective SA exposuretime on increasing the plant defence and decreasing the nematode parasitismin Solanum lycopersicum. In addition, effects of SA treatment on theexpression Pathogenesis Related Gene 5 (PR5) was evaluated. For this aim,tomato seedlings were exposed within 1000µM SA concentration withdistinctive time durations. The expression of PR5 gene was accomplishedusing RT-PCR at 1, 3, 7, 14, 21 days post infection (dpi) for each sample. Rootgalling index, nematode number and reproduction rate were evaluated.Results revealed that nematode reproduction rate was decreased at in longerdurations after SA treatment on roots. The highest nematode reproduction ratewas determined in nematode+water (non-SA treatment) application compareto SA treatments. The highest increased level of expression of SlPR5 genewas determined in early (1 dpi) SA treatment + nematode infection. Toconclude, SA treatment may increase the plant defence mechanisms and PR5gene may involve in nematode-plant parasitism.