Evaluation of Resistance and Biochemical Responses of Different Barley Cultivars in Interaction with Meloidogyne incognita

Document Type : Research Article

Authors

1 Ferdowsi University of Mashhad, Agriculture Faculty, Plant Pathology Department

2 Plant Protection Department. Agriculture Faculty. Ferdowsi University

3 Ferdowsi University of Mashhad

Abstract

Abstract

Meloidogyne incognita is the most well-known root-knot nematode, with more than 2000 host species. Integrated nematode management is recommended to manage the destructive plant parasitic nematode. Integrated management is generally performed by using the maximum available management methods (at least two methods) and the minimum use of chemical nematicides to bring the pathogen population below the economic threshold. The use of resistant cultivars is of particular importance in integrated management, due to environmental compatibility, economic efficiency, and sometimes the impossibility of implementing other methods in developing countries. Therefore, it is necessary to evaluate the resistance of the important barley plant (Hordeum vulgare) to prevent damage and also to investigate nematode interactions with it. In the current study, the resistance of different barley cultivars (Nik, Nimrouz, and Zarjow) was evaluated based on plant growth factors (length, fresh, and dry weight of aerial part and roots) and nematode reproduction (number of galls and egg mass in root system, number of eggs per egg mass, number of second juveniles in the soil, final population, and reproductive factor) at 60 days post inoculation. Then the activity of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) enzymes was measured on days 0, 1, 2, 3, and 4 days post inoculation. Regarding the mean number of galls, Nik cultivar showed a significant difference compared to Nimroz and Zarjow cultivars (P ≤ 0.05). However, no significant difference was observed between Nimroz and Zarjow cultivars. Based on plant growth factors, M. incognita nematode was found to have a negative effect on aerial part length and weight and a positive effect on root weight. Evaluation of the gall index and nematode reproduction factor (GI ≥ 2, and RF < 1) also showed that the three cultivars are hyper-susceptible and small galls are well formed in them. SOD enzyme in Nik, Nimrouz, and Zarjow showed maximum activity in 2.72, 1.91, and 2.15 U mg-1 protein on the 4, 4, and 3 days post inoculation, respectively. The enzyme in Nik was determined to be 1.42 and 1.25 times higher than Nimrouz and Zarjow. There was a significant difference between 0, 1, and 2 with the 3 and 4 days of the infected samples in Nik (P ≤ 0.05). In the other cultivars, enzyme activity increased with a slight slope. CAT enzyme peaked in Nik, Nimrouz, and Zarjow at 0.204, 0.09, and 0.11 μmol min-1 mg-1 protein on the fourth-day post inoculation. In the Nik cultivar, unlike the other two cultivars, the enzyme increased more and had a steep slope from the second to the fourth day. In infected plants of Nimrouz, despite the gradual increase of enzyme, no significant difference was found between any of the days. APX enzyme peaked at 0.26, 0.27, and 0.24 μmol min-1 mg-1 protein in Nik, Nimrouz, and Zarjow on the fourth day, respectively. The activity of the above enzyme had an increasing trend in three cultivars. The maximum activity of this enzyme was at Nimrouz, which was determined to be 1.03 and 1.1 times higher than Nik and Zarjow, respectively. In this cultivar, the upward trend was rapid, although there was a significant difference between all-time points at the level of 0.05. In the current research, it was found that the invasion of the root-knot nematode M. incognita reduces the growth of length, fresh and dry weight in the aerial part, reduces the length of the root but increases the fresh weight of it. The hallmark of inducing pathogenicity in the sedentary root-knot nematodes is the formation of special feeding cells named giant cells, which requires controlling the expression of host genes and manipulation of plant hormones like auxin and cytokinin hormones. It is obvious that during the invasion of root-knot nematodes and the formation of giant cells, the plant is weakened due to impaired transport of water and nutrients, and the host growth factors, especially in the aerial part, are reduced. However, due to hormonal disorders and formation of galls, the weight of the roots increases. The increase in antioxidant enzymes superoxide dismutase, catalase and ascorbate peroxidase has occurred due to the compatible interaction, as a result of lack of necrosis and programmed cell death and to tolerate stress (nematode invasion).

Keywords: antioxidant enzymes, barley, gall, nematode, resistance

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Main Subjects


جلد 36 شماره 4 سال 1401

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