Weedy rice refers to the unwanted plants of the genus Oryza that have some undesirable agronomic traits and pose a major threat to sustainable rice production worldwide. Widespread adoption of direct seeded rice and hybridization or gene flow between cultivated rice and their wild relatives has resulted in the creation and dissemination of weedy rice. Currently, weedy rice (Oryza sativa f. spontanea) has become one of the most common weeds infesting rice fields worldwide. In this paper, we review the biology, physiology, evolution, and genetic features of weedy rice. We also discuss the major obstacles in weedy rice management, including high diversity of weedy rice, ecological impacts of gene flow on weedy rice, changing climate, and weedy rice management. We then present a framework for the sustainable management and utilization of weedy rice. Our main emphasis is to explore the reservoir of natural variations in weedy germplasm and to utilize them for crop improvement. This review outlines some of the latest biotechnological tools to dissect the genetic backgrounds of several favorable traits of weedy rice that may prove beneficial for breeding and evolutionary studies on cultivated rice. We suggest that by merging the disciplines of genomics, breeding, and weed management, we can achieve the goal of sustainable rice production.

The main constraints of current hybrid rice technology using male sterility (MS) are the low yield and high labor costs of hybrid rice seed (HRS) production. Therefore, there is an urgent need for innovative new hybrid rice technology. Fortunately, we discovered a unique spontaneous sporophytic female-sterile rice mutant controlled by a single recessive locus in the nucleus. Because female-sterile mutant lines cannot produce any selfed-seeds but their pollen has totally normal functions, female sterility (FS) lines may be considered ideal pollen donors to replace the female-fertile pollen donor parent lines currently used in the HRS production. In this study, a genetically engineered FS-based system was constructed to propagate a pure transgene-free FS line using a bentazon herbicide screening. Additionally, the ability of the FS + MS (FM)-line system, with mixed plantings of FS and MS lines, to produce HRS was tested. The pilot field experiment results showed that HRS of the FM-line system was more efficient compared with the conventional FS to MS strip planting control mode. Thus, this study provides new insights into genetic engineering technology and a promising strategy for the utilization of FS in hybrid rice.

Background: There is limited understanding of tracheal carcinoma (TC) because of its rarity. We examined the efficacy of radiotherapy (RT) for patients with primary TC. Methods: We analyzed the records of 32 patients with primary TC who received RT at our center between November 1996 and December 2016. Results: Thirteen patients received adjuvant RT and 18 received definitive RT. Eight patients achieved complete remission (CR) after definitive RT. Among all patients, the 5-year overall survival (OS) rate was 46.9% and the locoregional progression free survival (LRPFS) rate was 68.1%. Univariate analysis indicated the 5-year OS was better in those with adenoid cystic adenocarcinoma than squamous cell carcinoma ( P = 0.001); the 5-year LRPFS was better in patients who received surgical resection than those who did not (92.9% vs 46.4%, P = 0.013) and in patients who received postoperative RT than in those who received definitive RT (91.7% vs 50.1%, P = 0.038). A sub-group univariate analysis indicated the 5-year PFS was better for those who received at least 68 Gy of radiation (44.4% vs 13.0%, P = 0.044). Patients who achieved CR had a better 5-year PFS than those who did not (57.1% vs 10%, P = 0.006). No patients had a toxicity of grade 3 or more. Conclusions: Adjuvant and definitive RT are safe and effective treatments for TC. Patients who received dosages of 68 Gy or more and who had complete tumor regression following definitive RT seemed to have better long-term survival.

The embryo sac plays a vital role in sexual reproduction of angiosperms. LysM domain containing proteins with multiple lysin motifs are widespread proteins and are involved in plant defense responses against fungal chitins and bacterial peptidoglycans. Various studies have reported the role of LysM domain-containing proteins in plant defense mechanisms but their involvement in sexual reproduction remains largely unknown. Here, we report the involvement of a LysM domain-containing gene, EMBRYO SAC 1 (OsEMSA1), in the sexual reproduction of rice. The gene encoded a LysM domain-containing protein that was necessary for embryo sac development and function. The gene was expressed in root, stem, leaf tissues, panicle and ovaries and had some putative role in hormone regulation. Suppression of OsEMSA1 expression resulted in a defective embryo sac with poor differentiation of gametophytic cells, which consequently failed to attract pollen tubes and so reduced the panicle seed-setting rate. Our data offers new insight into the functions of LysM domain-containing proteins in rice.

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In this study, we carried out a classification survey on sterile plants in the F1 population of high-quality and high-yield Dian-type japonica hybrid rice 'Dianheyou 34', combining with the basic agronomic traits and biological information of the backbone restorer line 'Nan34' and its mutant Rf1 restorer gene lost mutant, the phenomenon and cause of function loss of restorer lines were preliminarily explored. The results showed that the loss of function with natural mutation at Rf1 in 'Nan34' was the main factor that led to sterile plants (two years accounted for 0.26% and 0.79% respectively) in 'Dianheyou 34'F1 hybrid population; the seed setting rate of 'Nan34' wild type was no significant difference compared with its mutant, and the wild type was slightly higher than the mutant in pollen fertility, plant height, ear length and grain length, and slightly greater than the wild type in grain width. By cloning the Rf1 locus of 'Nan34' wild type and its mutant, we found that the mutant in ORF region lost a 574 bp long sequence compared with the wild type, which made it unable to encode some PPR proteins. The loss of this sequence may lead to the loss of recovery function. The results lay a theoretical foundation for revealing genetic variation mechanism of restorer genes in three-line hybrid rice breeding and utilization.

Background To compare the maternal and neonatal outcomes of placenta previa (PP) with and without coverage of a uterine scar in Foshan, China. Methods A retrospective cohort study comparing all singleton pregnancies with PP was conducted at a tertiary, university-affiliated medical center from 1 January 2012 to 31 April 2017 in Foshan, China. Demographic, clinical and laboratory data were extracted from electronic medical records. Maternal and neonatal outcomes of PP with and without coverage of a uterine scar were compared by statistical method. Results There were 58,062 deliveries during the study period, of which 738 (1.27%) were complicated PP in singleton pregnancies and were further classified into two groups: the PP with coverage of a uterine scar group (PPCS, n = 166) and the PP without coverage of a uterine scar group (Non-PPCS, n = 572). Overall, premature birth (< 37 weeks,68.1% vs 54.8%; P = 0.010), cesarean section(100% vs 97.6%; P = 0.042), Intraoperative blood loss > 1000 ml (78.3% vs 16.0%; P < 0.001) or > 3000 ml (29.5% vs 3.0%; P < 0.001), postpartum hemorrhage(48.8% vs 15.7%; P < 0.001), transfusion (35.2% vs 16.1%; P < 0.001), hemorrhage shock(8.4% vs 1.9%; P < 0.001), hysterectomy (3.0% vs 0.5%; P = 0.006) and fetal distress (36.1% vs 12.0%; P < 0.001) had a significant difference between PPCS group and Non-PPCS group. After grouping by whether complicated with AIP, we found that PPCS was significant associated with more intraoperative blood loss༞1000 ml, intraoperative blood loss༞3000 ml, bleeding within 2–24 hours after delivery, fetal distress and higher hospitalization expenses than the Non-PPCS group. After grouping by whether complicated with AIP and different placenta positions(Anterior, Posterior and Ante-posterior or laterally positioned), we found that PPCS was significant associated with more intraoperative blood loss༞1000 ml and higher hospitalization expenses than the Non-PPCS in AIP women and more intraoperative blood loss༞1000 ml, postpartum hemorrhage and higher hospitalization expenses in Non-AIP women. Conclusion The PPCS group had poorer maternal and neonatal outcomes than the Non-PPCS group after grouping by whether pregnancies complicated with AIP or with different placental positions.