ABSTRACT
Fungal communities colonizing Ophiocordyceps spp. plays a crucial ecological role in their natural habitat, contributing to infect the host larvae, and influencing their occurrence. Although associated fungi with the newly described Ophiocordyceps indica, from the Indian Western Himalaya remains unclear. Therefore, we untangled the culturable fungal communities associated with O. indica and soil adhered to it, collected from low-height areas of Himachal Pradesh, India. The study resulted in the identification of 111 fungal isolates representing 17 families, with maximum fungal isolates (36.03%) within Cordycipitaceae. Interestingly, a total of 24 genera were found associated with O. indica and adhered soil, of which 12 were common, 8 were exclusive to O. indica and 4 were only limited to soil. Additionally, the influence of soil physicochemical parameters on fungal diversity indices revealed a positive correlation with humidity and available nitrogen and a negative correlation with pH and available phosphorus. These findings provide insights into the culturable fungal diversity of O. indica and the soil adhering to it, thus can contribute to the understanding of host-microbial interactions. Furthermore, these associations can be explored as a source of bioactive metabolites to combat the unending industrial demands.
Subject(s)
Hypocreales , Mycobiome , Humans , Himalayas , Ecosystem , Soil , Soil MicrobiologyABSTRACT
Historically, some edible insects have been processed into a complex of insect and fungus, such as Antherea pernyi and Samsoniella hepiali. Until now, the dynamics of the nutritional changes due to this infection were unclear. This study reveals the dynamic changes in nutritional components of Antherea pernyi pupa after infection with Samsoniella hepiali at post-infection time points of 0 d, 10 d, 20 d, and 30 d. The dynamic analysis of the components at different post-infection times showed that the content of polysaccharides and cordycepin increased with time while the content of fats and chitin decreased. The content of proteins showed a trend of decreasing at the beginning and then increasing. The essential amino acids (EAAs) decreased at the beginning and then increased, and non-essential amino acids (NEAA) changed similarly. The essential amino acid index showed a slight continuous decrease. Although the crude fat decreased dramatically due to the infection, from a value of 30.75% to 7.2%, the infection of S. hepiali produced five new fatty acids (14-methyl-pentadecanoic acid, docosanoic acid, succinic acid, arachidonic acid, and myristic acid) while the content of the seven fatty acids was greatly reduced after infection. Therefore, after being infected by S. hepiali and combined with it, the nutritional profile of A pernyi pupa was changed significantly and there were different characteristics at different infection stages. The above findings provide scientifically fundamental data to understand the nutritional value of the insect-fungus complex as human food and animal feed.
ABSTRACT
Ophiocordyceps sinensis is a highly valued fungus that has been used as traditional Asian medicine. This fungus is one of the most important sources of income for the nomadic populations of the Tibetan Plateau. With global warming and excessive collection, the wild O. sinensis resources declined dramatically. The cultivation of O. sinensis hasn't been fully operational due to the unclear genetic basis of the fruiting body development. Here, our study conducted pairwise comparisons between transcriptomes acquired from different growth stages of O. sinensis including asexual mycelium (CM), developing fruiting body (DF) and mature fruiting body (FB). All RNA-Seq reads were aligned to the genome of O. sinensis CO18 prior to comparative analyses. Cluster analysis showed that the expression profiles of FB and DF were highly similar compared to CM. Alternative splicing analysis (AS) revealed that the stage-specific splicing genes may have important functions in the development of fruiting body. Functional enrichment analyses showed that differentially expressed genes (DEGs) were enriched in protein synthesis and baseline metabolism during fruiting body development, indicating that more protein and energy might be required for fruiting body development. In addition, some fruiting body development-associated genes impacted by ecological factors were up-regulated in FB samples, such as the nucleoside diphosphate kinase gene (ndk), ß subunit of the fatty acid synthase gene (cel-2) and the superoxide dismutase gene (sod). Moreover, the expression levels of several cytoskeletons genes were significantly altered during all these growth stages, suggesting that these genes play crucial roles in both vegetative growth and the fruiting body development. Quantitative PCR (qPCR) was used to validate the gene expression profile and the results supported the accuracy of the RNA-Seq and DEGs analysis. Our study offers a novel perspective to understand the underlying growth stage-specific molecular differences and the biology of O. sinensis fruiting body development.
ABSTRACT
Diaprepes abbreviatus (Coleoptera: Curculionidae) is a root weevil, introduced from the Caribbean Basin into Florida in 1964. The larval stage feeds on fibrous and structural roots of citrus, predisposing the injured root system to infection and girdling by Phytophthora spp. In citrus orchards, the rootstocks trifoliate orange (Poncirus trifoliata) and hybrid 'Swingle' citrumelo (Citrus paradisi × P. trifoliata) are resistant to the complex of P. nicotianae with D. abbreviatus, while 'Cleopatra' mandarin (C. reticulata) is susceptible to this complex. When Phytophthora palmivora is coincident with P. nicotianae in fine-textured, poorly drained soils, Swingle citrumelo is more vulnerable to attack by the complex with P. palmivora than is Cleopatra mandarin. Infestation of 9-month-old seedlings with zero, two, or five neonate larvae resulted in a wide range of fibrous root and taproot damage of trifoliate orange and Cleopatra mandarin. Leakage of reducing sugars increased sharply as injury to the roots exceeded 75%. The relationship between feeding damage and root leakage was similar for the two rootstocks. Thus, reduced root damage was not based on host resistance to larval feeding. Root infection and rhizosphere populations of P. nicotianae were higher on Cleopatra mandarin than on trifoliate orange. Root rot by P. nicotianae did not increase with severity of feeding injury on either rootstock. Root infection and root rot by P. palmivora was more severe on trifoliate orange than on Cleopatra mandarin and increased with severity of larval damage. P. palmivora infected and rotted the taproot of both rootstocks if predisposed by larval feeding, but P. nicotianae did not. Commercial rootstocks are severely damaged by larvae of D. abbreviatus; therefore, tolerance of the Phytophthora-Diaprepes weevil complex should be based on resistance of rootstocks to each Phytophthora sp.