Cucumber is one of the most popular vegetables grown in tropical and subtropical regions of India. Survey revealed that the incidence of viral diseases on cucumber ranged from 45 to 100 per cent. During survey, hundred cucumber plant samples showing the virus-like disease symptoms were collected from farmer’s fields of Uttar Pradesh state, India and were tested by ELISA and PCR. Out of the hundred samples, fifteen samples showed positive for CGMMV, twelve for PRSV-W, eleven for GBNV, fourteen for CMV, eight for ZYMV, twenty for begomovirus and twenty samples showed mixed infection with different combination of RNA viruses (CGMMV, CMV, PRSV-W and GBNV) and begomoviruses. The positive PCR amplicons of begomoviruses (the partial genome comprising 1.2kb fragment) were sequenced and results showed that, the begomovirus associated with twenty samples were closely related to the known bipartite begomovirus species, Tomato leaf curl New Delhi virus (ToLCNDV). One representative sample (Cb-1) was selected for amplification of full length sequences of genome components (DNA A and DNA B) and betasatellite and alphasatellite by RCA method. The sequence analysis showed that the cucumber isolate (Cb-1) shared maximum nucleotide (nt) identity of 94.2 -96.1 per cent with ToLCNDV infecting chilli. The betasatellite and alphasatellite characterized here showed high levels of nt identity of 87.6-93.4 per cent with Tomato leaf curl Jodeypur betasatellite (ToLCJoB) and 76.2-94.9 per cent with isolates of Okra leaf curl alphasatellite (OLCuDD1), respectively. An analysis for recombinant origin of genome (DNA A and DNA B) and betasatellite showed major part of their genome was likely, originated by recombination of previously reported begomoviruses infecting different host species resulting in evolution of new recombinant virus. However, alphasatellite is non recombinant in nature. Further, the cucumber lines belong to different species were screened against ToLCNDV showed that two accessions (EC-595881 and EC-595926) and nine accessions (EC-595839, EC-595922, VRC-27, VRC-26, SPP-88, SPP-56, VRC-09-08, Sarta and US-832) belongs to Cucumis sativus showed resistant and moderately resistant reaction, respectively. Accession SPP-44 belongs to Cucumis melo var. momordica showed moderate resistance, accession SPP-37 of Cucumis melo var. agrestis showed moderate resistance and accession (IC-297507) of Cucumis melo var. conomon showed moderate resistance towards begomovirus infection.The significance of these findings is discussed.

The microalgae represent the vast source of bioactive compounds with the potential for industrial products such as pharmaceuticals, cosmetics, food supplements, molecular probes, fine chemicals, and agrochemicals. Several novel metabolites with potent pharmacological properties have been discovered from the marine organisms among them, 25 percent are from algae. Astaxanthin is a strong antioxidant for several health applications. It is a metabolite of zeaxanthin and canthaxanthin, containing hydroxyl and ketone functional groups which is a lipophilic terpene made up of carbon precursors. Astaxanthin cannot be synthesized by humans, only can be absorbed alongside fatty acids via passive diffusion. They are transported to body tissues to protect the cells and lipid-based membranes against oxidative damage. The structure of astaxanthin facilitates it as an excellent antioxidant with free radical scavenging property, mitochondrial protection, anti-inflammatory effects, and protection from glycation. But for a beneficial strategy in health management and carry forward the further research using astaxanthin for gaining more reliable results, a piece of precise information is needed, which can only be accessed from good reviews. Here in this review, we will try to give information regarding the natural source of astaxanthin, market demands, and various applications specifically focused on the human health sector.