Jasmonates are essential phytohormones for plant development and survival. However, the molecular details of their signalling pathway remain largely unknown. The identification more than a decade ago of COI1 as an F-box protein suggested the existence of a repressor of jasmonate responses that is targeted by the SCF(COI1) complex for proteasome degradation in response to jasmonate. Here we report the identification of JASMONATE-INSENSITIVE 3 (JAI3) and a family of related proteins named JAZ (jasmonate ZIM-domain), in Arabidopsis thaliana. Our results demonstrate that JAI3 and other JAZs are direct targets of the SCF(COI1) E3 ubiquitin ligase and jasmonate treatment induces their proteasome degradation. Moreover, JAI3 negatively regulates the key transcriptional activator of jasmonate responses, MYC2. The JAZ family therefore represents the molecular link between the two previously known steps in the jasmonate pathway. Furthermore, we demonstrate the existence of a regulatory feed-back loop involving MYC2 and JAZ proteins, which provides a mechanistic explanation for the pulsed response to jasmonate and the subsequent desensitization of the cell.

No abstract

All critical developmental and physiological events in a plant's life cycle depend on the proper activation and repression of specific gene sets, and this often involves epigenetic mechanisms. Some mutants with disorders of the epigenetic machinery exhibit pleiotropic defects, including incurved leaves and early flowering, due to the ectopic and heterochronic derepression of developmental regulators. Here, we studied one such mutant class, the () loss-of-function mutants. We have identified as the founding member of a small gene family that we have named (). This family is part of the 2-oxoglutarate/Fe(II)-dependent dioxygenase superfamily. and its closest paralog, have unequally redundant functions: although mutants are phenotypically wild type, double mutants skip vegetative development and flower upon germination. This phenotype is reminiscent of loss-of-function mutants of the Polycomb-group genes () and Double mutants harboring alleles and loss-of-function alleles of genes encoding components of the epigenetic machinery exhibit synergistic, severe phenotypes, and some are similar to those of mutants. Hundreds of genes are misexpressed in plants, including (), and derepression of causes the leaf phenotype of ICU11 and CP2 are nucleoplasmic proteins that act as epigenetic repressors through an unknown mechanism involving histone modification, but not DNA methylation.

The mapping method detailed here is based on the multiplex polymerase chain reaction (PCR) coamplification of 32 molecular markers, using fluorescently labeled oligonucleotides as primers. For the genotyping of a single plant from a mapping population, only two simultaneous amplifications are required, the products of which are finally electrophoresed in an automated DNA sequencer controlled by fragment analysis software. An analysis of the genotypes of 50 plants allows mapping of the mutation of interest within a candidate genomic interval of about 15 cM (3 Mb, corresponding to about 40 BAC clones).

Uterine microbiota may be involved in reproductive health and disease. This study aims to describe and compare the vaginal and endometrial microbiome patterns between women who became pregnant and women who did not after in vitro fertilization. We also compared the vaginal and endometrial microbiome patterns between women with and without a history of repeated implantation failures (RIF). This pilot prospective cohort study included 48 women presenting to the fertility clinic for IVF from May 2017 to May 2019. Women who achieved clinical pregnancy presented a greater relative abundance of Lactobacillus spp. in their vaginal samples than those who did not (97.69% versus 94.63%; p = 0.027. The alpha and beta diversity of vaginal and endometrial samples were not statistically different between pregnant and non-pregnant women. The Faith alpha diversity index in vaginal samples was lower in women with RIF than those without RIF (p = 0.027). The alpha diversity of the endometrial microbiome was significantly higher in women without RIF (p = 0.021). There were no significant differences in the vaginal and endometrial microbiomes between pregnant and non-pregnant women. The relative abundance of the genera in women with RIF was different from those without RIF. Statistically significant differences in the endometrial microbiome were found between women with and without RIF.