No abstract

Job’s tears (Coix lacryma-jobi L.) is an ancient plant with high nutritional and medicinal values. In this study, using 11 Job’s tears germplasm resources collected throughout China, we examined genetic differences among germplasms and differences in the in vitro antioxidant activities of coixan and sought to identify inter-relationships between these two variables. We found that the intraspecific conservation of DNA sequences was high, with ITS regions and cpDNA trnL-F and trnH-psbA non-coding sequences showing no sequence variation, whereas the GBSSI gene showed a certain degree of variation among the different Job’s tears germplasms. EST-SSR analysis also revealed a relatively low level of genetic diversity among germplasms. Coixan was shown to be an efficient antioxidant, and among the germplasms examined, the LNYX, FJPC and AHBZ had the highest antioxidant activities. However, none of the four in vitro antioxidant activity indices we assessed were significantly correlated with the geographical origin of the germplasm (latitude and longitude), and one of them had significantly associated with genetic diversity. Although the factors affecting the antioxidant activity of coixan are complex, the role of heredity should not be ignored. Our findings have implications for the scientific evaluation, identification and sustainable utilization of Job’s tears germplasm resources.

Ophiocordyceps sinensis Berk. is a fungal parasite that parasitizes the larvae of Hepialidae and is used as a traditional Chinese medicine. However, it is not clear how O. sinensis infects its host. The encoding gene haplotype diversity and predicted function of the nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome P450 reductase (CPR) related to the fungal pathogenicity was analyzed for 219 individuals from 47 O. sinensis populations. Two NADPH CPR genes of O. sinensis were detected and their dominant haplotypes were widely distributed throughout the entire distribution range in Western China. Only 5.43% of all O. sinensis individuals possessed the specific private haplotypes of NADPH CPR-1 and CPR-2 genes. Bioinformatic analyses predicted that the phosphorylation sites, motifs, and domains of NADPH CPR of O. sinensis were different between those encoding by the dominant and private gene haplotypes. The one-to-one match fungus–host correspondence of the same individual suggested that the widely distributed O. sinensis with the dominant NADPH CPR gene haplotypes may strongly infect almost all host insects through a random infection by oral or respiratory pores. Conversely, O. sinensis with the specific private NADPH CPR gene haplotypes is likely to infect only a few corresponding host insects by breaching the cuticle, due to the changed NADPH CPR structure and function.

No abstract