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Updated: Jun 24, 2026
Screening Cotton Genotypes for Reniform Nematode Resistance
Published on: May 2, 2019
Free Amino Acids in Roots of Infected Cotton Seedlings Resistant and Susceptible to Meloidogyne incognita
Abstract:
Quantities of free amino acids in segments of cotton roots resistant and susceptible to Meloidogyne incognita were compared. Following infection, the root-knot susceptible cultivar, M8, had greater percentage increases of certain individual free amino acids than the resistant cultivar, Clevewilt, but the sum total of free amino acids was greatest in the resistant cultivar. More free amino acids were present in infected than in noninfected plants of both cultivars. The overall concn of glycine declined over the I 0-day period following inoculation. The concns of the aromatic amino acids, tyrosine and phenylalanine, varied as functions of infection, cultivar, and time of harvest. Proline in susceptible M8 increased nearly 2000-fold 10 days after infection, when considerable thickening of syncytial walls is occurring.
Insights
Cotton root-knot nematode infection alters free amino acid levels. Resistant cottons accumulate more total amino acids, while susceptible ones show specific increases, particularly proline, during syncytial development.
Area of Science:
- Plant Pathology
- Biochemistry
- Nematology
Background:
- Meloidogyne incognita (root-knot nematode) causes significant damage to cotton.
- Amino acid profiles in plants can be altered by biotic stress.
- Understanding these biochemical changes is crucial for developing resistant crop varieties.
Purpose of the Study:
- To compare free amino acid quantities in cotton roots resistant and susceptible to Meloidogyne incognita.
- To investigate the dynamic changes in amino acid concentrations following nematode infection over time.
Main Methods:
- Quantitative analysis of free amino acids in cotton root segments.
- Comparison between resistant (Clevewilt) and susceptible (M8) cultivars.
- Assessment at different time points post-inoculation with Meloidogyne incognita.
Main Results:
- Both resistant and susceptible cultivars showed increased total free amino acids post-infection.
- Susceptible cultivar M8 exhibited greater percentage increases in specific amino acids.
- Proline concentration in susceptible M8 roots increased dramatically (nearly 2000-fold) 10 days post-infection, coinciding with syncytial wall thickening.
Conclusions:
- Cotton root free amino acid composition is significantly influenced by Meloidogyne incognita infection.
- Resistant cultivars maintain higher total free amino acids under infection.
- The substantial proline increase in susceptible roots suggests a role in nematode-induced plant responses and syncytial development.
