BackgroundHevea brasiliensis, a member of the Euphorbiaceae family, is the major commercial source of natural rubber (NR). NR is a latex polymer with high elasticity, flexibility, and resilience that has played a critical role in the world economy since 1876.ResultsHere, we report the draft genome sequence of H. brasiliensis. The assembly spans ~1.1 Gb of the estimated 2.15 Gb haploid genome. Overall, ~78% of the genome was identified as repetitive DNA. Gene prediction shows 68,955 gene models, of which 12.7% are unique to Hevea. Most of the key genes associated with rubber biosynthesis, rubberwood formation, disease resistance, and allergenicity have been identified.ConclusionsThe knowledge gained from this genome sequence will aid in the future development of high-yielding clones to keep up with the ever increasing need for natural rubber.
The alkaline gut of Lepidopterans plays a crucial role in shaping communities of bacteria. Enterococcus mundtii has emerged as one of the predominant gut microorganisms in the gastrointestinal tract of the major agricultural pest, Spodoptera littoralis. Therefore, it was selected as a model bacterium to study its adaptation to harsh alkaline gut conditions in its host insect throughout different stages of development (larvae, pupae, adults, and eggs). To date, the mechanism of bacterial survival in insects' intestinal tract has been unknown. Therefore, we have engineered a GFP-tagged species of bacteria, E. mundtii, to track how it colonizes the intestine of S. littoralis. Three promoters of different strengths were used to control the expression of GFP in E. mundtii. The promoter ermB was the most effective, exhibiting the highest GFP fluorescence intensity, and hence was chosen as our main construct. Our data show that the engineered fluorescent bacteria survived and proliferated in the intestinal tract of the insect at all life stages for up to the second generation following ingestion.
The complex interaction between a higher organism and its resident gut flora is a subject of immense interest in the field of symbiosis. Many insects harbor a complex community of microorganisms in their gut. Larvae of Spodoptera littoralis, a lepidopteran pest which is prevalent in tropical and subtropical regions of the world, have a tube-like gut structure containing a simple bacterial community. This community varies both spatially (along the length of the gut) and temporally (during the life cycle of the insect).To monitor the dynamics and rapid adaptation of microbes to the gut conditions, a GFP-tagged reporter E. mundtii was constructed. After feeding to early instar S. littoralis larvae, the taggedmicrobes recovered from the fore and hind guts by flow cytometry. The fluorescent reporter confirmed the persistence of E. mundtii in the gut. RNA-sequencing of the sorted bacteria highlighted various strategies that the symbiont employs to survive, including upregulated pathways for tolerating alkaline stress, forming biofilms and two-component signaling systems, resisting oxidative stress and quorum sensing. Although these symbionts depend on the host for amino acid and fatty acids, differential regulation among various metabolic pathways points to an enriched lysine synthesis pathway in the hindgut of the larvae.
21The complex interaction between a higher organism and its resident gut flora is a subject of 22 immense interest in the field of symbiosis. Many insects harbor a complex community of 23 microorganisms in their gut. Larvae of Spodoptera littoralis, a lepidopteran pest which is 24 prevalent in tropical and subtropical regions of the world, have a tube-like gut structure 25 containing a simple bacterial community. This community varies both spatially (along the 26 length of the gut) and temporally (during the life cycle of the insect). 27To monitor the dynamics and rapid adaptation of microbes to the gut conditions, a GFP-tagged 28 reporter E. mundtii was constructed. After feeding to early instar S. littoralis larvae, the tagged-29 microbes recovered from the fore and hind guts by flow cytometry. The fluorescent reporter 30 confirmed the persistence of E. mundtii in the gut. RNA-sequencing of the sorted bacteria 31 highlighted various strategies that the symbiont employs to survive, including upregulated 32 pathways for tolerating alkaline stress, forming biofilms and two-component signaling systems, 33 resisting oxidative stress and quorum sensing. Although these symbionts depend on the host for 34 amino acid and fatty acids, differential regulation among various metabolic pathways points to 35 an enriched lysine synthesis pathway in the hindgut of the larvae. 36 37 animals, pests or pollinators of food crops, and as cyclers of carbon and nitrogen during the 43 decomposition of plant biomass (1) 44 There are several factors that determine the gut bacterial composition in insects. The gut can be 45 compartmentalized, resulting in structures that vary according to the complexity of the microbial 46 communities. Insects with a straight, tube-like gut usually possess a less diverse microbial 47 population compared to species with invaginations and deep pouches (1). Other factors that 48 shape the gut population include the following: oxygen level, gut pH, the presence of digestive 49 enzymes, antimicrobial compounds, and insect diet (2, 3). Although most bacteria have an 50 affinity for neutral pH, several acidophiles and alkalophiles have adapted to extreme pH 51 conditions. 52 Gut microbes can be either vertically or horizontally transmitted. Vertical transmission allows 53 bacterial transfer (from the ovaries to the egg shells) to the next generation (4), whereas 54 horizontal transmission occurs over the course of the life cycle, through diet and social behavior. 55 Regardless of how bacteria are transmitted, microbial populations may be unstable during early 56 developmental stages (5, 6). For example, in holometabolous insects, a complete metamorphosis 57 of the gut occurs in the larva, through pupal and adult stages, resulting in microbial turnover and 58 variable microbial counts (5).59 Insects are helped by their bacterial and fungal symbionts with functions relating to the digestion 60 of complex plant carbohydrates and amino acids, the assimilation of vitamins and the 61 development of defensive str...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.