Strigolactones (SLs) are a new class of carotenoid-derived phytohormones essential for developmental processes shaping plant architecture and interactions with parasitic weeds and symbiotic arbuscular mycorrhizal fungi. Despite the rapid progress in elucidating the SL biosynthetic pathway, the perception and signaling mechanisms of SL remain poorly understood. Here we show that DWARF53 (D53) acts as a repressor of SL signaling and SLs induce its degradation. We found that the rice d53 mutant, which produces an exaggerated number of tillers compared to wild type plants, is caused by a gain-of-function mutation and is insensitive to exogenous SL treatment. The D53 gene product shares predicted features with the class I Clp ATPase proteins and can form a complex with the α/β hydrolase protein DWARF14 (D14) and the F-box protein DWARF3 (D3), two previously identified signaling components potentially responsible for SL perception. We demonstrate that, in a D14- and D3-dependent manner, SLs induce D53 degradation by the proteasome and abrogate its activity in promoting axillary bud outgrowth. Our combined genetic and biochemical data reveal that D53 acts as a repressor of the SL signaling pathway, whose hormone-induced degradation represents a key molecular link between SL perception and responses.

nature biotechnology advance online publication l e t t e r sThe brown planthopper (BPH) is the most destructive pest of rice (Oryza sativa) and a substantial threat to rice production, causing losses of billions of dollars annually 1,2 . Breeding of resistant cultivars is currently hampered by the rapid breakdown of BPH resistance 2 . Thus, there is an urgent need to identify more effective BPH-resistance genes. Here, we report molecular cloning and characterization of Bph3, a locus in rice identified more than 30 years ago that confers resistance to BPH. We show that Bph3 is a cluster of three genes encoding plasma membrane-localized lectin receptor kinases (OsLecRK1-OsLecRK3). Introgression of Bph3 into susceptible rice varieties by transgenic or marker-assisted selection strategies significantly enhanced resistance to both the BPH and the white back planthopper. Our results suggest that these lectin receptor kinase genes function together to confer broad-spectrum and durable insect resistance and provide a resource for molecular breeding of insect-resistant rice cultivars.BPH (Nilaparvata lugens Stål, Hemiptera, Delphacidae) is a monophagous, phloem-sucking herbivore. It sucks the sap from the rice phloem using its stylet, and causes direct damage to rice plants. BPH can also cause indirect damage to rice plants through the transmission of viruses including the rice ragged stunt virus and grassy stunt virus 2 . Repeated overapplication of pesticides for BPH management has heavily polluted the environment 3 . Breeding of resistant cultivars is the most cost-effective and environmentally responsible strategy for BPH management but developing insect resistant cultivars by traditional breeding approaches is extremely difficult and time consuming owing to a paucity of knowledge about BPH resistance genes and germplasm.To date, 28 BPH resistance loci have been identified from cultivated and wild species of Oryza 2,4,5 . Only two of these resistance genes, Bph14 and Bph26 have been cloned to date 6,7 . In addition, BPH resistance of IR26 and IR36, two widely cultivated rice varieties that harbor the BPH resistance loci Bph1 and bph2, respectively, was quickly broken down in just a few years owing to the rapid adaptation of the BPH 8 . Thus, there is still an urgent need to identify new types of resistance genes and germplasm for developing efficient approaches to breed broad-spectrum and durable BPH-resistant rice cultivars. Notably, the Bph3 locus, originally identified in the Sri Lankan indica cultivar Rathu Heenati 9 , displayed resistance to four BPH biotypes (BPH biotypes refer to specific populations of BPH classified according to their virulence on different BPH resistance genes) 2,10 . Furthermore, rice varieties harboring Bph3 deployed more than 30 years ago in the Philippines are still resistant to BPH 8 . However, the molecular basis of this broad-spectrum and durable resistance of Bph3 against BPH remains unknown.We observed that Bph3-containing Rathu Heenati infested with BPH of mixed biotypes (biotype ...

Grain size is a major determinant of grain yield in cereal crops. qSW5/GW5, which exerts the greatest effect on rice grain width and weight, was fine-mapped to a 2,263-bp/21-kb genomic region containing a 1,212-bp deletion, respectively. Here, we show that a gene encoding a calmodulin binding protein, located ∼5 kb downstream of the 1,212-bp deletion, corresponds to qSW5/GW5. GW5 is expressed in various rice organs, with highest expression level detected in young panicles. We provide evidence that the 1,212-bp deletion affects grain width most likely through influencing the expression levels of GW5. GW5 protein is localized to the plasma membrane and can physically interact with and repress the kinase activity of rice GSK2 (glycogen synthase kinase 2), a homologue of Arabidopsis BIN2 (BRASSINOSTEROID INSENSITIVE2) kinase, resulting in accumulation of unphosphorylated OsBZR1 (Oryza sativa BRASSINAZOLE RESISTANT1) and DLT (DWARF AND LOW-TILLERING) proteins in the nucleus to mediate brassinosteroid (BR)-responsive gene expression and growth responses (including grain width and weight). Our results suggest that GW5 is a novel positive regulator of BR signalling and a viable target for genetic manipulation to improve grain yield in rice and perhaps in other cereal crops as well.

BackgroundSub-therapeutic antibiotics are widely used as growth promoters in the poultry industry; however, the resulting antibiotic resistance threatens public health. A plant-derived growth promoter, Macleaya cordata extract (MCE), with effective ingredients of benzylisoquinoline alkaloids, is a potential alternative to antibiotic growth promoters. Altered intestinal microbiota play important roles in growth promotion, but the underlying mechanism remains unknown.ResultsWe generated 1.64 terabases of metagenomic data from 495 chicken intestinal digesta samples and constructed a comprehensive chicken gut microbial gene catalog (9.04 million genes), which is also the first gene catalog of an animal’s gut microbiome that covers all intestinal compartments. Then, we identified the distinctive characteristics and temporal changes in the foregut and hindgut microbiota. Next, we assessed the impact of MCE on chickens and gut microbiota. Chickens fed with MCE had improved growth performance, and major microbial changes were confined to the foregut, with the predominant role of Lactobacillus being enhanced, and the amino acids, vitamins, and secondary bile acids biosynthesis pathways being upregulated, but lacked the accumulation of antibiotic-resistance genes. In comparison, treatment with chlortetracycline similarly enriched some biosynthesis pathways of nutrients in the foregut microbiota, but elicited an increase in antibiotic-producing bacteria and antibiotic-resistance genes.ConclusionThe reference gene catalog of the chicken gut microbiome is an important supplement to animal gut metagenomes. Metagenomic analysis provides insights into the growth-promoting mechanism of MCE, and underscored the importance of utilizing safe and effective growth promoters.Electronic supplementary materialThe online version of this article (10.1186/s40168-018-0590-5) contains supplementary material, which is available to authorized users.

Flowering time (i.e., heading date in crops) is an important ecological trait that determines growing seasons and regional adaptability of plants to specific natural environments. Rice (Oryza sativa L.) is a short-day plant that originated in the tropics. Increasing evidence suggests that the northward expansion of cultivated rice was accompanied by human selection of the heading date under noninductive long-day (LD) conditions. We report here the molecular cloning and characterization of DTH2 (for Days to heading on chromosome 2), a minor-effect quantitative trait locus that promotes heading under LD conditions. We show that DTH2 encodes a CONSTANS-like protein that promotes heading by inducing the florigen genes Heading date 3a and RICE FLOWERING LOCUS T 1, and it acts independently of the known floral integrators Heading date 1 and Early heading date 1. Moreover, association analysis and transgenic experiments identified two functional nucleotide polymorphisms in DTH2 that correlated with early heading and increased reproductive fitness under natural LD conditions in northern Asia. Our combined population genetics and network analyses suggest that DTH2 likely represents a target of human selection for adaptation to LD conditions during rice domestication and/or improvement, demonstrating an important role of minor-effect quantitative trait loci in crop adaptation and breeding.

In China, ages at menarche and menopause are not associated with diabetes. Later menarche and menopause are associated with decreasing CVD risk and earlier menopause with higher osteoporosis risk. Menarche and menopause history may help identify women with increased risk of developing CVD and osteoporosis.

In seed plants, a major pathway for sorting of storage proteins to the protein storage vacuole (PSV) depends on the Golgi-derived dense vesicles (DVs). However, the molecular mechanisms regulating the directional trafficking of DVs to PSVs remain largely elusive. Here, we report the functional characterization of the rice (Oryza sativa) glutelin precursor accumulation3 (gpa3) mutant, which exhibits a floury endosperm phenotype and accumulates excess proglutelins in dry seeds. Cytological and immunocytochemistry studies revealed that in the gpa3 mutant, numerous proglutelin-containing DVs are misrouted to the plasma membrane and, via membrane fusion, release their contents into the apoplast to form a new structure named the paramural body. Positional cloning of GPA3 revealed that it encodes a plant-specific kelch-repeat protein that is localized to the trans-Golgi networks, DVs, and PSVs in the developing endosperm. In vitro and in vivo experiments verified that GPA3 directly interacts with the rice Rab5a-guanine exchange factor VPS9a and forms a regulatory complex with Rab5a via VPS9a. Furthermore, our genetic data support the notion that GPA3 acts synergistically with Rab5a and VPS9a to regulate DV-mediated post-Golgi traffic in rice. Our findings provide insights into the molecular mechanisms regulating the plant-specific PSV pathway and expand our knowledge of vesicular trafficking in eukaryotes.

Rice MONOCULM 1 (MOC1) and its orthologues LS/LAS (lateral suppressor in tomato and Arabidopsis) are key promoting factors of shoot branching and tillering in higher plants. However, the molecular mechanisms regulating MOC1/LS/LAS have remained elusive. Here we show that the rice tiller enhancer (te) mutant displays a drastically increased tiller number. We demonstrate that TE encodes a rice homologue of Cdh1, and that TE acts as an activator of the anaphase promoting complex/cyclosome (APC/C) complex. We show that TE coexpresses with MOC1 in the axil of leaves, where the APC/CTE complex mediates the degradation of MOC1 by the ubiquitin–26S proteasome pathway, and consequently downregulates the expression of the meristem identity gene Oryza sativa homeobox 1, thus repressing axillary meristem initiation and formation. We conclude that besides having a conserved role in regulating cell cycle, APC/CTE has a unique function in regulating the plant-specific postembryonic shoot branching and tillering, which are major determinants of plant architecture and grain yield.