Effect of Stem Gall Disease Caused by Protomyces macrosporus on Biochemical Changes of Coriander

Aim: Stem gall diseases have become major economic significance. The disease manifests itself in the form of galls on stem, branches, leaves, petioles and fruits, causes 15-20 per cent yield loss and deteriorates quality of seeds. Quantitative biochemical changes are required to determine for development of resistant variety against stem gall Methodology: Stem gall symptoms were regularly observed during whole crop growth stage from appearance of symptom on different parts of the coriander plants. The leaves, stems, inflorescence, petioles and fruits showing characteristic symptoms were separately collected and kept in rough dry envelopes and marked clearly mentioning location, infected parts, variety, reaction types, date of collection etc. and brought to the laboratory for identification of the pathogen and used for the study of biochemical changes such as total phenol, tannins, flavonoids and Saponins Results: The stem gall symptoms were observed as small tumour-like swellings on all herbaceous parts of the affected plants, namely, stems, petioles, flower stalks and leaves. The mycelium of Protomyces macrosporus was septate, hyaline, irregular, branched, 2 to 5 μm thick, 36.50 μm length and 35.00 μm width. Intercellular and multinucleate mycelium’s are formed Chlamydospores, which are globose to ellipsoid, thick-walled, three-layered membrane and smooth with brownish colour. Mature Chlamydospores were multinucleate and measured 60-70 μm x 50-60 μm in diameter. Severely infected plant parts have synthesized low amount of phenol, tannin, flavonoid and saponin content, whereas comparatively high amount of these compounds are found in less infected plant parts or healthy one Interpretation: Stem gall infected plant parts were immediately accumulate total phenol, tannin, saponin and flavonoids following the pathogenic attack in resistant varieties, whereas susceptible varieties did not accumulate significantly higher amount of these substances.