摘要：
In an experiment across China to test integrated soil–crop system management for rice, wheat and maize against current practice, improvements in grain yield are equivalent to high-input techniques, but nutrient use, nutrient loss and greenhouse gas emissions are lower than current practice. Integrated soil–crop system management is a technique that aims to maximize yield and minimize environmental impact by adapting cropping systems to local conditions through optimal nutrient application, seasonal timing and the use of the best crop varieties. Fusuo Zhang and colleagues report the results of a China-wide test of this technique for the three main cereal crops — rice, wheat and maize. In comparisons with current practice and high input techniques, the authors find that the integrated system achieves yield improvements equivalent to high input techniques but with lower nutrient use, nutrient loss and greenhouse gas emissions than those found with the current practice. Agriculture faces great challenges to ensure global food security by increasing yields while reducing environmental costs1,2. Here we address this challenge by conducting a total of 153 site-year field experiments covering the main agro-ecological areas for rice, wheat and maize production in China. A set of integrated soil–crop system management practices based on a modern understanding of crop ecophysiology and soil biogeochemistry increases average yields for rice, wheat and maize from 7.2million grams per hectare (Mgha−1), 7.2Mgha−1 and 10.5Mgha−1 to 8.5Mgha−1, 8.9Mgha−1 and 14.2Mgha−1, respectively, without any increase in nitrogen fertilizer. Model simulation and life-cycle assessment3 show that reactive nitrogen losses and greenhouse gas emissions are reduced substantially by integrated soil–crop system management. If farmers in China could achieve average grain yields equivalent to 80% of this treatment by 2030, over the same planting area as in 2012, total production of rice, wheat and maize in China would be more than enough to meet the demand for direct human consumption and a substantially increased demand for animal feed, while decreasing the environmental costs of intensive agriculture.
摘要：
MAX2 (for MORE AXILLARY GROWTH2) has been shown to regulate diverse biological processes, including plant architecture, photomorphogenesis, senescence, and karrikin signaling. Although karrikin is a smoke-derived abiotic signal, a role for MAX2 in abiotic stress response pathways is least investigated. Here, we show that the max2 mutant is strongly hypersensitive to drought stress compared with wild-type Arabidopsis (Arabidopsis thaliana). Stomatal closure of max2 was less sensitive to abscisic acid (ABA) than that of the wild type. Cuticle thickness of max2 was significantly thinner than that of the wild type. Both of these phenotypes of max2 mutant plants correlate with the increased water loss and drought-sensitive phenotype. Quantitative real-time reverse transcription-polymerase chain reaction analyses showed that the expression of stress-responsive genes and ABA biosynthesis, catabolism, transport, and signaling genes was impaired in max2 compared with wild-type seedlings in response to drought stress. Double mutant analysis of max2 with the ABA-insensitive mutants abi3 and abi5 indicated that MAX2 may function upstream of these genes. The expression of ABA-regulated genes was enhanced in imbibed max2 seeds. In addition, max2 mutant seedlings were hypersensitive to ABA and osmotic stress, including NaCl, mannitol, and glucose. Interestingly, ABA, osmotic stress, and drought-sensitive phenotypes were restricted to max2, and the strigolactone biosynthetic pathway mutants max1, max3, and max4 did not display any defects in these responses. Taken together, these results uncover an important role for MAX2 in plant responses to abiotic stress conditions.
摘要：
Polyploidization has provided much genetic variation for plant adaptive evolution, but the mechanisms by which the molecular evolution of polyploid genomes establishes genetic architecture underlying species differentiation are unclear. Brassica is an ideal model to increase knowledge of polyploid evolution. Here we describe a draft genome sequence of Brassica oleracea, comparing it with that of its sister species B. rapa to reveal numerous chromosome rearrangements and asymmetrical gene loss in duplicated genomic blocks, asymmetrical amplification of transposable elements, differential gene co-retention for specific pathways and variation in gene expression, including alternative splicing, among a large number of paralogous and orthologous genes. Genes related to the production of anticancer phytochemicals and morphological variations illustrate consequences of genome duplication and gene divergence, imparting biochemical and morphological variation to B. oleracea. This study provides insights into Brassica genome evolution and will underpin research into the many important crops in this genus.
作者：
Chalhoub, Boulos;Denoeud, France;Liu, Shengyi;Parkin, Isobel A. P.;Tang, Haibao;...
期刊：
Science,2014年345(6199):950-953 ISSN：0036-8075
通讯作者：
Chalhoub, B.
作者机构：
[Samans, Birgit; Snowdon, Rod J.] Department of Plant Breeding, Research Center for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany.;[Guan, Mei; Liu, Zhongsong; Guan, Chunyun] College of Agronomy, Hunan Agricultural University, Changsha 410128, China.;[Town, Christopher D.] J. Craig Venter Institute, Rockville, MD 20850, USA.;Center for Genomics and Biotechnology, Fujian Agriculture and Forestry, University, Fuzhou 350002, Fujian Province, China.;[Renault, Victor] Fondation Jean Dausset–Centre d’Étude du Polymorphisme Humain, 27 rue Juliette Dodu, 75010 Paris, France.
通讯机构：
[Boulos Chalhoub] I;[Isobel A. P. Parkin; David Edwards] A;[Yongming Zhou; Andrew G. Sharpe] N;[Wei Hua] K;[Andrew H. Paterson] P
摘要：
Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72× genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.
作者：
Chalhoub, Boulos*;Denoeud, France;Liu, Shengyi;Parkin, Isobel A. P.;Tang, Haibao;...
期刊：
Science,2014年345(6199):950-953 ISSN：0036-8075
通讯作者：
Chalhoub, Boulos
作者机构：
[Vinh Ha Dinh Thi; Mestiri, Imen; Chalabi, Smahane; Jabbari, Kamel; Just, Jeremy; Lu, Yunhai; Arnaud, Dominique; Canaguier, Aurelie; Le Clainche, Isabelle; Chalhoub, Boulos; Chelaifa, Houda; Belcram, Harry] Univ Evry Val dEssone, Inst Natl Rech Agron INRA, Unite Rech Genom Vegetale, UMR1165, F-91057 Evry, France.;[Da Silva, Corinne; Denoeud, France; Bento, Pascal; Wincker, Patrick; Labadie, Karine; Alberti, Adriana; Correa, Margot; Noel, Benjamin; Bernard, Maria; Aury, Jean-Marc; Battail, Christophe] Commissariat Energie Atom CEA, Inst Genom IG, F-91057 Evry, France.;[Denoeud, France; Wincker, Patrick] Univ Evry Val dEssone, UMR 8030, F-91057 Evry, France.;[Denoeud, France; Wincker, Patrick] Ctr Natl Rech Sci CNRS, UMR 8030, Evry, France.;[Hu, Qiong; Wang, Xinfa; Tong, Chaobo; Liu, Shengyi; Hua, Wei] Chinese Acad Agr Sci, Key Lab Biol & Genet Improvement Oil Crops, Minist Agr Peoples Republ China, Oil Crops Res Inst, Wuhan 430062, Peoples R China.
通讯机构：
[Chalhoub, Boulos] U;Univ Evry Val dEssone, Inst Natl Rech Agron INRA, Unite Rech Genom Vegetale, UMR1165, 2 Rue Gaston Cremieux, F-91057 Evry, France.
摘要：
Oilseed rape (Brassica napus L.) was formed ∼7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72x genome multiplication since the origin of angiosperms and high gene content.We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.
关键词：
Rice;Spiders;Drosophila melanogaster;Food web structure;Arthropoda;Genetically modified plants;Pest control;Spider webs
摘要：
Cry proteins are expressed in rice lines for lepidopteran pest control. These proteins can be transferred from transgenic rice plants to non-target arthropods, including planthoppers and then to a predatory spider. Movement of Cry proteins through food webs may reduce fitness of non-target arthropods, although recent publications indicated no serious changes in non-target populations. Nonetheless, Cry protein intoxication influences gene expression in Cry-sensitive insects. We posed the hypothesis that Cry protein intoxication influences enzyme activities in spiders acting in tri-trophic food webs. Here we report on the outcomes of experiments designed to test our hypothesis with two spider species. We demonstrated that the movement of CryAb protein from Drosophila culture medium into fruit flies maintained on the CryAb containing medium and from the flies to the spiders Ummeliata insecticeps and Pardosa pseudoannulata. We also show that the activities of three key metabolic enzymes, acetylcholine esterase (AchE), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) were significantly influenced in the spiders after feeding on Cry1Ab-containing fruit flies. We infer from these data that Cry proteins originating in transgenic crops impacts non-target arthropods at the physiological and biochemical levels, which may be one mechanism of Cry protein-related reductions in fitness of non-target beneficial predators.
摘要：
Plants must effectively defend against biotic and abiotic stresses to survive in nature. However, this defense is costly and is often accompanied by significant growth inhibition. How plants coordinate the fluctuating growth-defense dynamics is not well understood and remains a fundamental question. Jasmonate (JA) and gibberellic acid (GA) are important plant hormones that mediate defense and growth, respectively. Binding of bioactive JA or GA ligands to cognate receptors leads to proteasome-dependent degradation of specific transcriptional repressors (the JAZ or DELLA family of proteins), which, at the resting state, represses cognate transcription factors involved in defense (e.g., MYCs) or growth [e.g. phytochrome interacting factors (PIFs)]. In this study, we found that the coi1 JA receptor mutants of rice (a domesticated monocot crop) and Arabidopsis (a model dicot plant) both exhibit hallmark phenotypes of GA-hypersensitive mutants. JA delays GA-mediated DELLA protein degradation, and the della mutant is less sensitive to JA for growth inhibition. Overexpression of a selected group of JAZ repressors in Arabidopsis plants partially phenocopies GA-associated phenotypes of the coi1 mutant, and JAZ9 inhibits RGA (a DELLA protein) interaction with transcription factor PIF3. Importantly, the pif quadruple (pifq) mutant no longer responds to JA-induced growth inhibition, and overexpression of PIF3 could partially overcome JA-induced growth inhibition. Thus, a molecular cascade involving the COI1-JAZ-DELLA-PIF signaling module, by which angiosperm plants prioritize JA-mediated defense over growth, has been elucidated.
摘要：
Applying biochar to soils may cause a win-win situation resulting in C sequestration and soil fertility improvement. The effect may be more evident in highly weathered and infertile tropical soils, but will be dependent on biochar quality. An Ultisol, typical to southern China, was used to evaluate amendment with biochars produced by a range of temperatures and durations, to investigate its effects on soil properties and plant growth. Rice straw-derived biochars were charred at temperatures from 250 to 450 degrees C for between 2 and 8 h. The increase of temperature caused smaller less structured (as viewed by SEM) fragments to form with less 0, H and aliphatic C functional groups, but more aromatic C as indicated by infrared spectroscopy. The mean residence time of biochars under controlled conditions (25 degrees C, 40% field capacity) was estimated from 244 to 1700 years, generally increasing with charring temperature and duration. Amendment of 1% biochar increased pH by 0.1-0.46 (P < 0.01) and CEC by 3.9-17.3% (P < 0.05), but had no effect on aggregate stability. In pot trials maize biomass was increased by 64% (without NPK) to 146% (with NPK) after biochar amendment. The study emphasizes that amendment with biochar can improve soil fertility at least in the short term. Future studies focusing on the persistence of biochar fertility in the field must explicitly take into account additional factors to transfer this technology. (C) 2011 Elsevier B.V. All rights reserved.
