Rice plant architecture is an important agronomic trait and a major determinant in high productivity. Panicle erectness is the preferred plant architecture in japonica rice, but the molecular mechanism underlying domestication of the erect panicle remains elusive. Here we report the map-based cloning of a major quantitative trait locus, qPE9-1, which plays an integral role in regulation of rice plant architecture including panicle erectness. The R6547 qPE9-1 gene encodes a 426-amino-acid protein, homologous to the keratin-associated protein 5-4 family. The gene is composed of three Von Willebrand factor type C domains, one transmembrane domain, and one 4-disulfide-core domain. Phenotypic comparisons of a set of near-isogenic lines and transgenic lines reveal that the functional allele (qPE9-1) results in drooping panicles, and the loss-of-function mutation (qpe9-1) leads to more erect panicles. In addition, the qPE9-1 locus regulates panicle and grain length, grain weight, and consequently grain yield. We propose that the panicle erectness trait resulted from a natural random loss-of-function mutation for the qPE9-1 gene and has subsequently been the target of artificial selection during japonica rice breeding.

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Purpose: How exosomal RNAs released within the bone marrow microenvironment affect proteasome inhibitors' (PI) sensitivity of multiple myeloma is currently unknown. This study aims to evaluate which exosomal RNAs are involved and by which molecular mechanisms they exert this function.Experimental Design: Exosomes were characterized by dynamic light scattering, transmission electron microscopy, and Western blot analysis. Coculture experiments were performed to assess exosomal RNAs transferring from mesenchymal stem cells (MSC) to multiple myeloma cells. The role of PSMA3-AS1 in PI sensitivity was further evaluated in vivo. To determine the prognostic significance of circulating exosomal PSMA3 and PSMA3-AS1, a cohort of patients with newly diagnosed multiple myeloma was enrolled to study. Cox regression models and Kaplan-Meier curves were used to analyze progression-free survival (PFS) and overall survival (OS).Results: We identified that PSMA3 and PSMA3-AS1 in MSCs could be packaged into exosomes and transferred to myeloma cells, thus promoting PI resistance. PSMA3-AS1 could form an RNA duplex with pre-PSMA3, which transcriptionally promoted PSMA3 expression by increasing its stability. In xenograft models, intravenously administered siPSMA3-AS1 was found to be effective in increasing carfilzomib sensitivity. Moreover, plasma circulating exosomal PSMA3 and PSMA3-AS1 derived from patients with multiple myeloma were significantly associated with PFS and OS.Conclusions: This study suggested a unique role of exosomal PSMA3 and PSMA3-AS1 in transmitting PI resistance from MSCs to multiple myeloma cells, through a novel exosomal PSMA3-AS1/PSMA3 signaling pathway. Exosomal PSMA3 and PSMA3-AS1 might act as promising therapeutic targets for PI resistance and prognostic predictors for clinical response.

The current nitrogen fertilization for sugarcane production in Guangxi, the major sugarcane-producing area in China, is very high. We aim to reduce nitrogen fertilization and improve sugarcane production in Guangxi with the help of indigenous sugarcane-associated nitrogen-fixing bacteria. We initially obtained 196 fast-growing bacterial isolates associated with the main sugarcane cultivar ROC22 plants in fields using a nitrogen-deficient minimal medium and screened out 43 nitrogen-fixing isolates. Analysis of 16S rRNA gene sequences revealed that 42 of the 43 nitrogen-fixing isolates were affiliated with the genera Enterobacter and Klebsiella. Most of the nitrogen-fixing enterobacteria possessed two other plant growth-promoting activities of IAA production, siderophore production and phosphate solubilization. Two Enterobacter spp. strains of NN145S and NN143E isolated from rhizosphere soil and surface-sterilized roots, respectively, of the same ROC22 plant were used to inoculate micropropagated sugarcane plantlets. Both strains increased the biomass and nitrogen content of the sugarcane seedlings grown with nitrogen fertilization equivalent to 180 kg urea ha−1, the recommended nitrogen fertilization for ROC22 cane crops at the seedling stage. 15N isotope dilution assays demonstrated that biological nitrogen fixation contributed to plant growth promotion. These results suggested that indigenous nitrogen-fixing enterobacteria have the potential to fix N2 associated with sugarcane plants grown in fields in Guangxi and to improve sugarcane production.