Detection of nematicidal compounds and development of an in vitro mass multiplication protocol in Pusa Centenary Chrysanthemum

Abstract

Phytopathogenic nematodes are the major threat to agricultural crop productivity. Biopesticides can be safe and effective alternative to the harmful chemical pesticides. In this study the effect of Chrysanthemum cv. Pusa Centenary against Meloidogyne incognita was examined and the active chemical constituents were explored using LC-MS. To meet the growing demand protocol for in vitro mass propagation of Pusa centenary was also established. The aqueous extract of shoot and root showed significant mortality against second stage juveniles (J2s) and was directly related to the concentration and exposure time and it reached a maximum of 99.2% with 10% shoot extract after 72h. Insight into the chemical composition of Pusa Centenary using LCMS revealed the presence of total 12 bioactive compounds (11 flavonoids and a terpene). The regeneration was obtained via somatic embryogenesis from petal explants in Chrysanthemum cv. Pusa centenary. Petal explants produced direct somatic embryos within 10-14 days on Murashige and Skoog (MS) media containing, 2, 4-Dichlorophenoxyacetic acid (2, 4-D) (1 mg L-1) and ἀ-naphthalene acetic acid (NAA) (1 mg L-1) along with 0.5 mg L-1of 6-benzylaminopurine (BAP). On transfer to light on MS media with BAP (0.5 mg L-1) and reduced auxins, the calli started turning green and proliferating into plantlets. The in vitro propagation protocol shall help in the mass production of this cultivar for isolation of these nematicidal compounds which may be used as a biopesticide (bionematicide).