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Chemical recycling of polymers to monomers presents a promising solution to the escalating crisis associated with plastic waste. Despite considerable progress made in this field, the primary efforts have been focused on redesigning new monomers to produce readily recyclable polymers. In contrast, limited research into the potential of seemingly "non‐polymerizable" monomers has been conducted. Herein, we propose a paradigm that leverages a "chaperone"‐assisted strategy to establish closed‐loop circularity for a "non‐polymerizable" α, β‐conjugated lactone, 5,6‐dihydro‐2H‐pyran‐2‐one (DPO). The resulting PDPO, a structural analogue of poly(δ‐valerolactone) (PVL), exhibits enhanced thermal properties with a melting point (Tm) of 114 °C and a decomposition temperature (Td,5%) of 305 °C. Notably, owing to the structural similarity between DPO and δ‐VL, the copolymerization generates semi‐crystalline P(DPO‐co‐VL)s irrespective of the DPO incorporation ratio. Intriguingly, the inherent C=C bonds in P(DPO‐co‐VL)s enable their convenient post‐functionalization via Michael‐addition reaction. Lastly, PDPO was demonstrated to be chemically recyclable via ring‐closing metathesis (RCM), representing a significant step towards the pursuit of enabling the closed‐loop circularity of "non‐polymerizable" lactones without altering the ultimate polymer structure. [ABSTRACT FROM AUTHOR]

Polydnaviruses (PDVs) are obligatory symbionts of parasitoid wasps and play an important role in suppressing host immune defenses. Although PDV genes that inhibit host melanization are known in Microplitis bracovirus, the functional homologs in Cotesia bracoviruses remain unknown. Here, we find that Cotesia vestalis bracovirus (CvBV) can inhibit hemolymph melanization of its host, Plutella xylostella larvae, during the early stages of parasitization, and that overexpression of highly expressed CvBV genes reduced host phenoloxidase activity. Furthermore, CvBV‐7‐1 in particular reduced host phenoloxidase activity within 12 h, and the injection of anti‐CvBV‐7‐1 antibody increased the melanization of parasitized host larvae. Further analyses showed that CvBV‐7‐1 and three homologs from other Cotesia bracoviruses possessed a C‐terminal leucine/isoleucine‐rich region and had a similar function in inhibiting melanization. Therefore, a new family of bracovirus genes was proposed and named as C‐terminal Leucine/isoleucine‐rich Protein (CLP). Ectopic expression of CvBV‐7‐1 in Drosophila hemocytes increased susceptibility to bacterial repression of melanization and reduced the melanotic encapsulation of parasitized D. melanogaster by the parasitoid Leptopilina boulardi. The formation rate of wasp pupae and the eclosion rate of C. vestalis were affected when the function of CvBV‐7‐1 was blocked. Our findings suggest that CLP genes from Cotesia bracoviruses encoded proteins that contain a C‐terminal leucine/isoleucine‐rich region and function as melanization inhibitors during the early stage of parasitization, which is important for successful parasitization. [ABSTRACT FROM AUTHOR]

Microsatellites, as the tracts of repetitive DNA, are an essential constituent of the plant genome that holds important evolutionary significance, and have been extensively used to develop molecular makers for genetic analysis. To understand the microsatellite dynamics of quinoa genome and its relatives, in this study we performed a genome‐wide analysis of microsatellites in five Amaranthaceae species using available genome sequences. The results demonstrated that the microsatellites of the five Amaranthaceae species were characterised by relatively high proportions of mono‐, di‐ and trinucleotide repeats with A/T rich motifs, implying conservative organisation and composition of microsatellites in this family. Furthermore, a significant negative correlation between microsatellite frequencies and GC contents (r = −.87) were observed. In total, 533,961 (89.57%) and 542,601 (89.86%) microsatellite loci could be used to develop simple sequence repeat (SSR) molecular markers, of which 7,178 were found to be polymorphic between the two sequenced quinoa cultivars, QQ74 and Real Blanca, through in silico PCR analysis. Finally, 15 SSR markers were randomly selected to validate their polymorphism across 12 quinoa accessions by wet‐lab PCR amplification. The newly developed genome‐wide SSR markers provide a useful resource for population genetics, gene mapping and molecular breeding studies in quinoa and beyond. [ABSTRACT FROM AUTHOR]