Plant-Parasitic Nematodes (Nematoda: Tylenchomorpha) Associated with Different Crops in the Damavand Region, with Descriptions of Two New Records for Iran

Document Type : Research Paper

Authors

• Farnaz Fekrat ¹
• Reza Ghaderi ²
• Ebrahim Pourjam ³
• Akbar Karegar Bideh ⁴

¹ Department of Plant Protection, Faculty of Agriculture, University of Jiroft, Jiroft, Iran.

² Department of Plant Protection, Faculty of Agriculture, Shiraz University, Shiraz, Iran

³ Department of Plant Pathology, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran

⁴ Department of Plant Protection, Faculty of Agriculture, Shiraz University, Shiraz, Iran.

Abstract

Keywords

• Identification
• Morphology
• Paratylenchus aciculus
• Rotylenchus elegans
• Taxonomy

Extended Abstract

Introduction

    Agricultural crops worldwide continually face threats from plant pathogens, including fungi, bacteria, viruses and nematodes. Among these, plant-parasitic nematodes—often referred to as the “hidden enemies” of plants—are frequently overlooked by farmers despite their significant impact (Kleynhans, 1996). Effective management of plant-parasitic nematodes requires a thorough understanding of their pathogenic effects on crops, which, in turn, depends on the precise identification of the nematode species. Accurate identification serves as the foundation for assessing nematode population dynamics and developing effective management strategies (‏‏‏‏Seesao et al., 2017). Numerous plant-parasitic nematodes from the infraorder Tylenchomorpha De Ley and Blaxter, 2002, have been reported from various agricultural regions in Iran (Ghaderi et al., 2018).

Several studies have examined nematode fauna in Tehran and Alborz provinces. Mojtahedi et al., (1980) identified 31 species across different genera within the family Tylenchorhynchidae in Iran. Notable species recovered from agricultural and horticultural hosts in these provinces include Merlinius brevidens from Ovin, Quinisulcius acti from Varamin, Tylenchorhynchus clarus from Savojbolagh, Taleqan, and Shahriar, Merlinius grandis from Karaj, M. stegus from Hesark, Shahriar and Savojbolagh and Amplimerlinius socialis from Hashtgerd and Savojbolagh. Additionally, the root-lesion nematode Pratylenchus vulnus, a highly damaging species, was also reported from the roots of plane trees (Barooti & Alavi, 2002). Saeedizadeh (2016) identified 28 species from 19 genera of plant-parasitic nematodes in Tehran’s green landscapes, with the genera Filenchus, Criconemoides, Helicotylenchus, Criconema and Pratylenchus exhibiting the highest species diversity.

Several other studies have also documented multiple species of plant-parasitic nematodes from different crops and localities whitin provinces (Hojjat Jalali, 1974; Karimipour Fard et al., 2002; Barooti & Khazini, 2008; Salehi, 2009; Lotfi & Gharekhani, 2013). Although the Damavand region covering 11,500 hectares of orchards and farmlands, comprehensive research on plant-parasitic nematode in this area remains limited. Consequently, this study aims to address this gap through morphology-based identification of plant-parasitic nematodes affecting diverse crops across the Damavand region.

Materials and Methods

To identify plant-parasitic nematodes in the orchards and fields of the Damavand region, 184 soil and root samples were collected from various rhizosphere soil of the crops during 2021-2022 (Table 1). Nematodes were extracted using the tray method (Whitehead & Hemming, 1965) and the sucrose centrifugation technique. (Jenkins, 1964). For light microscopy, specimens were heat-killed in a 4% formaldehyde solution and cleared with anhydrous glycerin following the De Grisse (1969) method.

Permanent microscope slides were prepared from the extracted nematodes. Measurements were taken with a Nikon E600 light microscope equipped with a drawing tube, and data were recorded and analyzed using Microsoft Office Excel® 2013. Nematode species were identified using standard nematology resources and estabilished identification keys.

The relative frequency of plant-parasitic nematodes was calculated using the formula:

Relative Frequency (%) = (No. of sampling units in which species occur)/ (Total number of sampling units used in the study) *100

soil sample per unit volume= 100 grams dry soil

This provided an estimate of the prevalence of each species within the sampled area.

Results and Discussion

Based on morphological and morphometric characteristics, 49 nematode species from 23 genera within the infraorder Tylenchomorpha were identified. The recovered nematodes belong to eight families: Anguinidae, Aphelenchoididae, Criconematidae, Dolichodoridae, Hoplolaimidae, Pratylenchidae, Tylenchidae and Tylenchulidae. Tylenchidae was the most widely distributed family, with a frequency of 17.1%. Despite their high abundance, these nematodes are often considered non-significant due to yield reductions. The recorded frequency percentages for major plant-parasitic nematodes within the families Hoplolaimidae, Pratylenchidae, Dolichodoridae, Criconematidae and Tylenchulidae were 11.4%, 8.7%, 8.7%, 5.4% and 5.4%, respectively.

Among economically important plant-parasitic nematodes, Helicotylenchus vulgaris and Pratylenchus neglectus were the most prevalent nematodes in the Damavand region, occurring in 6.0% and 5.4% of samples, respectively (Table 1). This study provides full descriptions, including morphological and morphometric diagnostic characters, line drawings and photomicrographs, for the two newly recorded species from Iran: Paratylenchus aciculus Brown, 1959 and Rotylenchus elegans (Khan & Khan, 1982) Fortuner, 1987.

Author Contributions

 “Conceptualization, Farnaz Fekrat and Reza Ghaderi ; methodology, Farnaz Fekrat.; software, Farnaz Fekrat.; validation, Farnaz Fekrat and Reza Ghaderi., formal analysis, Farnaz Fekrat.; investigation, Farnaz Fekrat, Reza Ghaderi, Ebrahim Pourjam and Akbar Karegar Bideh; resources, Farnaz Fekrat; data curation, Farnaz Fekrat.; writing—original draft preparation, Farnaz Fekrat.; writing—review and editing, Farnaz Fekrat and Reza Ghaderi.; supervision, Reza Ghaderi.; project administration, Farnaz Fekrat and Reza Ghaderi.; funding acquisition, Shiraz University and University of Jiroft. All authors have read and agreed to the published version of the manuscript.”

All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.

Data Availability Statement

Not applicable.

Acknowledgements

The authors would like to thank Shiraz University, Tarbiat Modares University and University of Jiroft for preparing the fund of research and also all participants of the present study.

Ethical considerations

The study was approved by the Ethics Committee of Shiraz University. The authors avoided data fabrication, falsification, plagiarism, and misconduct.

Conflict of interest

Nematology, Taxonomy.