Occurrence and molecular characterization of Meloidogyne graminicola on rice in Central Punjab, Pakistan.

Abdul Jabbar,Anam Moosa,Muhammad A Ali,Byron J Adams,Muhammad Jabran,Anjum Munir,Huma Abbas,Nazir Javed,Sajid A Khan

doi:10.21307/jofnem-2020-123

Abstract

Meloidogyne graminicola threatens global rice production, yet is understudied for many areas where it is cultivated. To better understand the prevalence and incidence of M. graminicola in central Punjab, Pakistan, we carried out field surveys of rice fields in the districts of Faisalabad and Chiniot. M. graminicola isolates were recovered from soil and root samples and identified on the basis of perineal patterns and rDNA ITS-based sequencing. The severity of nematode attack on rice roots and infested fields at various locations was based on galling index, root-knot nematode juveniles per root system, juveniles per 100 ml of soil, and prevalence of stylet-bearing nematodes and non-stylet-bearing nematodes. Maximum prevalence (22.5 and 27.5%) and minimum prevalence (17.5 and 20%) of M. graminicola was observed in Chiniot and Faisalabad, respectively. Eleven alternate host-plant species were examined in this study revealing varying degrees of M. graminicola infestation. ITS sequencing and phylogenetic analysis indicated that isolates from this study form a well-resolved clade with others from Asia, while another isolate falls outside of this clade in an unresolved polytomy with those from Europe and South America. Though monophyletic with the other M. graminicola, the isolates from Pakistan are distinguished by their high genetic variability and long branch lengths relative to the other isolates of M. graminicola, suggesting Pakistan as a possible ancestral area. Our results indicate that rice is severely attacked by a genetically diverse and aggressive M. graminicola, necessitating the development of appropriate control measures for its management in rice and other graminaceous crops.

Highlights

Rice (Oryza sativa L.) is one of the major cereal crops produced in Pakistan and is cultivated on an area of 2,900,600 hectares with a production of 11,174,700 tons (FAO, 2017)
Most of the rice fields in the present study were infested with M. graminicola that is not common in Punjab, Pakistan, because previously M. incognita has been reported as the predominant Root-knot nematodes (RKNs) prevailing in agroecosystems of Pakistan, which primarily attacks vegetable crops (Anwar et al, 2012)
The rice-growing fields of Chiniot and Faisalabad, Central Punjab, Pakistan are infested with M. graminicola

Summary

Introduction

Rice (Oryza sativa L.) is one of the major cereal crops produced in Pakistan and is cultivated on an area of 2,900,600 hectares with a production of 11,174,700 tons (FAO, 2017). Plant-parasitic nematodes are an emerging threat to rice production. There is no information available about the molecular identification of Meloidogyne spp. in Pakistan, especially in regard to M. graminicola. Several molecular techniques are available for the identification of Meloidogyne species (Blok and Powers, 2009). Among these techniques, the polymerase chain reaction (PCR) is a sensitive, quick, and accurate tool (Niu et al, 2011). We used morphological and mole cular approaches to identify RKNs in order to determine the distribution, prevalence, and disease intensity of M. graminicola in Chiniot and Faisalabad districts of Central Punjab, Pakistan

Methods

Results

Discussion

Conclusion