Response of tuberose genotypes to root knot nematode, Meloidogyne incognita: Biochemical, histological and nutritional characterization of host-pathogen interaction

• Published in: Journal of environmental biology 2019-11, Vol.40 (6), p.1151-1158
• Main Authors: Gandhi, D.P., Bharathi, T.U., Umamaheswari, R., Kalaivanan, D., Prathibha, S.
• Format: Article
• Language: English
• Subjects: Alanine; Ammonia; Biochemistry; Cell walls; Crop diseases; Crops; Eggs; Environmental science; Enzymes; Flowers & plants; Genotype & phenotype; Genotypes; Horticulture; Host-pathogen interactions; Inoculation; Manfreda; Meloidogyne incognita; Nematodes; Nutrients; Peroxidase; Pest resistance; Phenolic compounds; Phenols; Phenylalanine; Plant breeding; Polyphenol oxidase
• ISSN: 0254-8704; 2394-0379
• DOI: 10.22438/jeb/40/6/MRN-1069

Aim: The study was conducted to screen the tuberose genotypes for nematode resistance and to establish histopathological, biochemical and nutritional changes in resistant/tolerant genotype against root knot nematode, Meloidogyne incognita. Methodology: Twenty seven tuberose genotypes comprising of two types viz., single (18 genotypes) and double (9 genotypes) were evaluated for root knot nematode resistance. Tuberose bulbs of uniform size were surface sterilized and planted in 9 inch plastic pots and inoculated with nematode juveniles (J2) 15 days after planting. Gall Index was recorded on a 0-5 scale after 120 days of inoculation. Histopathological, biochemical (total phenols, peroxidase, polyphenol oxidase and phenylalanine ammonia lyase) and nutrient estimation studies were conducted on the roots of resistant/tolerant genotypes against root knot nematode, Meloidogyne incognita. Results: Among the twenty seven tuberose genotypes screened for nematode resistance, Suarna Rekha was categorized as resistant genotype and Arka Shlmgar, IIHR-2, IIHR-4, Variegated, IIHR-12, GK-TC4, Calcutta Double, Bidhan Rajanl-2 and Bidhan Rajanl-3 were categorized as tolerant genotypes. Histological characterization of resistant/tolerant genotypes revealed that giant cell formation was disrupted with higher number of phenolic cells and cells with lignlfied cell wall that prevented the successful establishment of nematode feeding site. The resistant and tolerant genotypes significantly recorded higher accumulation of phenols and defence enzymes viz., polyphenol oxidase (PPO), peroxidase (PO) and phenyl alanine ammonia lyase (PAL) and macro and micro nutrients as compared to susceptible genotypes. Interpretation: Screening of tuberose genotypes for root knot nematode resistance in this study has led to the identification of several nematode resistant/ tolerant genotypes. This would serve as a valuable information for the breeders to utilize resistant/ tolerant genotypes as parents in their breeding programmes.