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In present study, different varieties of chrysanthemum (Chrysanthemum × morifolium Ramat) were screened for total carotenoids, phenolic content and antioxidant activities. Among the genotypes studied, variety Jubilee (32.82 mg/100g) exhibited high total carotenoids followed by varieties Haldighati (26.71 mg/100 g), Little Orange (22.25 mg/100g), Liliput (20.77 mg/100g) and Star Yellow (19.21 mg/100g). Variety Jubilee also showed highest antioxidant activities of carotenoids {CUPRAC-Cupric reducing antioxidant capacity (149.44 μmol trolox/g), FRAP- Ferrous reducing power (40.09 %), DPPH radical scavenging activity (11.24%)}. The total phenolic content varied from 1.26 mg GAE/g (Ram Lal Dada) to 31.14 mg GAE/g (Jubilee) on fresh weight basis. Further, five promising varieties having high carotenoids, were quantified for lutein and β-carotene using High Performance Liquid Chromatography (HPLC). Highest lutein content was found in variety Jubilee (19.90 μg/g) followed by varieties Haldighati (8.67 μg /g), Liliput (4.77 μg /g), Star Yellow (3.93 μg /g) and Little Orange (3.69 μg/g). Highest β-carotene content was found in Little Orange (5.51μg/g) followed by the varieties Haldighati (2.04 μg /g), Jubilee (1.77 μg /g), Liliput (0.54 μg /g) and Star Yellow (0.50 μg/g). A high correlation between carotenoids, total phenolic and antioxidant activities was observed. Variety Sadwin Yellow showed highest total carotenoid (0.48 mg/g) in leaves, whereas chlorophyll a and total chlorophyll was highest in variety Punjab Anmol (1.32 mg/g, 1.56 mg/g) and high chlorophyll b in variety Pusa Aditya (0.28 mg/g).

Three native rhizobacteria, IRh9, IRh10 and IRh15, were isolated from nematode-infected tomato (Solanum lycopersicum L.) rhizosphere were characterized and evaluated for their efficacy against root-knot nematode (RKN), Meloidogyne incognita infecting tomato crop under pot conditions in the protected structure environment during 2020–21 at Centre for Protected Cultivation technology (CPCT), ICAR-Indian Agricultural Research Institute, New Delhi. Based on 16S rRNA sequences, IRh9, IRh10, and IRh15 showed > 98% homology with Bacillus licheniformis, Priestia megaterium and Pseudomonas putida, respectively. Compared to the control, the penetration of root-knot nematode in tomato roots was reduced by >50% under pot conditions through inoculation of these bacteria. Characterization through gas chromatography-mass spectrometry analysis revealed 30 different volatile organic compounds from these rhizobacteria. Among them, 19 compounds were identified from P. megaterium IRh10, followed by 16 compounds each from B. licheniformis IRh9 and P. putida IRh15. Furthermore, among the detected volatile organic compounds, acetic acid, hexadecane, hexadecanoic acid, octadecanoic acid, 1-decene and 9-octadeconoic acid are reported to possess nematicidal properties. Additional characterization of plant growth promotion traits associated with these rhizobacteria revealed that P. megaterium IRh10 and P. putida IRh15 produced indole acetic acid, while B. licheniformis IRh9 and P. megaterium IRh10 produced ammonia, but only P. putida IRh15 could solubilize the tricalcium phosphate under laboratory conditions. Among the 35 substrates studied, P. megaterium IRh10 utilized most (12), followed by B. licheniformis IRh9 and P. putida IRh15, which were able to use 11 and 8 substrates, respectively. The study showed that B. licheniformis IRh9, P. megaterium IRh10 and P. putida IRh15 are potential candidates for combating M. incognita infestation in tomato crops.

The fungus reported to be a potential antagonist of various soil and seed borne plant pathogens. C. globosum mycoparasitizes and produce antifungal metabolites which suppress the growth of the pathogenic fungi. Despite sufficient knowledge available on secondary metabolites of C. globosum and their wide biological activities, limited literatures are available on the polar active constituents and their potential use as antifungal agent. The study was carried out to evaluate chemical composition of secondary metabolites from C. globosum when it interacts with Bipolaris sorokiniana (2017-2020). The volatile compounds identified through GC-MS revealed that, C. globosum strain Cg2 produced a variety of antifungal secondary metabolites, i.e. octadecene trans-limonene oxide, dodecane, tetracosonal, heptacosanol and octadecanoic acid which may be involved in the antagonism. Similarly, UPLC-QToF-ESIMS analysis of chloroform soluble fraction of C. globosum (Cg2), B. sorokiniana (BS112) and their interaction (Cg2-BS112) were undertaken to identify non-volatile metabolites.These metabolites were identified as Chaetomugilin A, D, E, F, Globoxanthone A, Chaetoviridin A, B, E, Chaetoglobin B, Chaetoquadrin A, Chaetocochin B and F, Chaetoglobosin Q and N.The work indicates that the biocontrol agent C. globosum showed high antifungal metabolite production thereby antagonising B. sorokininana pathogen. The obtained data will greatly enrich current C. globosum metabolomic information and provide a good foundation for better understanding of biocontrol mechanism of C. globosum against plant pathogens and facilitating widespread application in the field of bio-control.