فهرست مطالب a. karegar

Systemic Acquired Resistance (SAR) as a management strategy for plant parasitic nematode is a state of resistance increased after a previous infection of plant to a biotic pathogen. Induction of SAR is accompanied by local and systemic enhancement of Salicylic Acid (SA). SA increase in plant is concomitant with PR1 expression. We examined the effect of three chemicals including SA, Abscisic Acid (ABA), and DL-β-Amino-n-Butyric Acid (BABA) on the root-knot nematode Meloidogyne incognita on tomato plants. The expression of PR1 genes and 9-Cis-Epoxycarotenoid Dioxygenase (NCED) as markers for SAR and ABA-related activity genes was investigated in growth chamber conditions. Results showed that all elicitors reduced the population of nematode as compared to the control. Shoot length, shoot fresh and dry weight of nematode infected tomatoes pre-treated with BABA increased by 20, 25, and 8 % and number of eggs, galls, egg masses and reproduction factor decreased by 33, 18, 18, and 20%, respectively. All elicitors increased the expression of PR1 and NCED genes in nematode infected tomato. These data suggest that SA, BABA and ABA activate similar defenses in tomato plants, which is partly SA- and ABA-related. SA, BABA, and ABA pretreated tomatoes infected with M. incognita trigger a SAR-response and lead to the control of the nematode under controlled conditions.

For identification of nematode species of the genera Ditylenchus and Nothotylenchus, 341 plant and soil samples from farms, orchards and pastures of Fars, Kohgiluye and Boyer-Ahmad, Bushehr and Hormozgan provinces, and 32 samples from Mazandaran, Golestan, Hamadan, Lorestan and Ilam provinces were collected, during 2013-2016. After extraction, killing and fixing, the extracted nematodes were transfered to anhydrous glycerol. Species identification was done using light microscope equipped with digital camera, based on morphometric and morphological characters. The results showed that the genera were existed in 54.7% of the samples. In this study, 12 species of Ditylenchus and five species of Nothotylenchus were identified. D. myceliophagus and D. medicaginis with 38.8% and 38.1% frequency, respectively, and N. geraerti with 60% frequency were the most common species. The species N. basiri, D. geraert and D. solani are new records and were described for the first time from Iran. Moreover, descriptions of N. adasi and N. medians, and the identification key for the Iranian species of the genera Ditylenchus and Nothotylenchus were provided.