作者机构：
[Wang, Guanqun; Li, Haoxuan; Zhang, Jianhua; Ye, Nenghui] Chinese Univ Hong Kong, Sch Life Sci, Shatin, Hong Kong 99077, Peoples R China.;[Wang, Guanqun; Li, Haoxuan; Zhang, Jianhua; Ye, Nenghui] Chinese Univ Hong Kong, State Key Lab Agrobiotechnol, Shatin, Hong Kong 99077, Peoples R China.;[Wang, Guanqun; Li, Haoxuan; Zhang, Jianhua] Hong Kong Baptist Univ, Dept Biol, Kowloon, Hong Kong 99077, Peoples R China.;[Meng, Shuan; Ye, Nenghui] Hunan Agr Univ, Coll Agr, Southern Reg Collaborat Innovat Ctr Grain & Oil, Changsha 410128, Peoples R China.;[Yang, Jianchang] Yangzhou Univ, Key Lab Crop Genet & Physiol Jiangsu Prov, Yangzhou 225099, Jiangsu, Peoples R China.
通讯机构：
[Zhang, Jianhua] C;[Zhang, Jianhua] H;Chinese Univ Hong Kong, Sch Life Sci, Shatin, Hong Kong 99077, Peoples R China.;Chinese Univ Hong Kong, State Key Lab Agrobiotechnol, Shatin, Hong Kong 99077, Peoples R China.;Hong Kong Baptist Univ, Dept Biol, Kowloon, Hong Kong 99077, Peoples R China.
摘要：
In rice (Oryza sativa), a specific temporary source organ, the stem, is important for grain filling, and moderate soil drying (MD) enhanced carbon reserve flow from stems to increase grain yield. The dynamics and biological relevance of DNA methylation in carbon reserve remobilization during grain filling are unknown. Here, we generated whole-genome single-base resolution maps of the DNA methylome in the stem. During grain filling under MD, we observed an increase in DNA methylation of total cytosines, with more hypomethylated than hypermethylated regions. Genes responsible for DNA methylation and demethylation were up-regulated, suggesting that DNA methylation changes in the stem were regulated by antagonism between DNA methylation and demethylation activity. In addition, methylation in the CG and CHG contexts was negatively associated with gene expression, while that in the CHH context was positively associated with gene expression. A hypermethylated/ up-regulated transcription factor of MYBS2 inhibited MYB30 expression and possibly enhanced b-Amylase5 expression, promoting subsequent starch degradation in rice stems under MD treatment. In addition, a hypermethylated/down-regulated transcription factor of ERF24 was predicted to interact with, and thereby decrease the expression of, abscisic acid 89-hydroxylase1, thus increasing abscisic acid concentration under MD treatment. Our findings provide insight into the DNA methylation dynamics in carbon reserve remobilization of rice stems, demonstrate that MD increased this remobilization, and suggest a link between DNA methylation and gene expression in rice stems during grain filling. Ó 2020 American Society of Plant Biologists. All Rights Reserved.
期刊：
International Journal of Molecular Sciences,2019年20(6):ARTN 1427 ISSN：1661-6596
通讯作者：
Zhang, Jian;Ao, Hejun
作者机构：
[Liu, Xixi; Li, Zhiyong; Hou, Yuxuan; Wang, Yifeng; Wang, Huimei; Tong, Xiaohong; Zhang, Jian] China Natl Rice Res Inst, State Key Lab Rice Biol, Hangzhou 311400, Zhejiang, Peoples R China;[Ao, Hejun] Hunan Agr Univ, Coll Agr Sci, Changsha 410128, Hunan, Peoples R China
通讯机构：
[Zhang, Jian] C;[Ao, Hejun] H;China Natl Rice Res Inst, State Key Lab Rice Biol, Hangzhou 311400, Zhejiang, Peoples R China. Hunan Agr Univ, Coll Agr Sci, Changsha 410128, Hunan, Peoples R China.
关键词：
ABA;SAPK;SnRK2s;bZIP;flowering time;rice (Oryza sativa L.)
摘要：
As core components of ABA signaling pathway, SnRK2s (Sucrose nonfermenting1(-)Related protein Kinase 2) bind to and phosphorylate AREB/ABF (ABA responsive element binding protein/ABRE-binding factor) transcriptional factors, particularly bZIPs (basic region-leucine zipper), to participate in various biological processes, including flowering. Rice contains 10 SnRK2 members denoted as SAPK1-10 (Stress-Activated Protein Kinase) and dozens of bZIPs. However, which of the SAPKs and bZIPs pair and involve in ABA signaling remains largely unknown. In this study, we carried out a systematical protein-protein interactomic analysis of 10 SAPKs and 9 ABA-inducible bZIPs using yeast-two-hybrid technique, and identified 14 positive interactions. The reliability of Y2H work was verified by in vitro pull-down assay of the key flowering regulator bZIP77 with SAPK9 and SAPK10, respectively. Moreover, SAPK10 could phosphorylate bZIP77 in vitro. Over-expression of SAPK10 resulted in earlier flowering time, at least partially through regulating the FAC-MADS15 pathway. Conclusively, our results provided an overall view of the SAPK-bZIP interactions, and shed novel lights on the mechanisms of ABA-regulated rice flowering.
摘要：
Millions of Chinese smallholder farmers were persuaded to adopt enhanced management practices, which led to a greater yield, reduced nitrogen fertilizer use and improved environmental performance throughout China. Two and a half billion smallholder farmers collectively manage 60 per cent of the world's arable land. How these farmers perform determines their own livelihood, but also affects global food security and ecosystem health. Here, Fusuo Zhang and colleagues show how some straightforward interventions have substantially improved the productivity and environmental performance of smallholder farmers across China over the past ten years. The team carried out more than 13,000 field trials across China's main agroecological zones and found that a series of management practices, collectively termed integrated soil–crop system management, increased maize, wheat and rice yields, nitrogen-use efficiency and farmer profitability. Scaling this approach up to 20.9 million smallholder farmer across 452 counties boosted grain yields to 33 million tonnes over the ten-year period, and reduced fertilizer use by 1.2 million tonnes and greenhouse gas emissions by up to 13 per cent. Sustainably feeding a growing population is a grand challenge1,2,3, and one that is particularly difficult in regions that are dominated by smallholder farming. Despite local successes4,5,6,7,8, mobilizing vast smallholder communities with science- and evidence-based management practices to simultaneously address production and pollution problems has been infeasible. Here we report the outcome of concerted efforts in engaging millions of Chinese smallholder farmers to adopt enhanced management practices for greater yield and environmental performance. First, we conducted field trials across China’s major agroecological zones to develop locally applicable recommendations using a comprehensive decision-support program. Engaging farmers to adopt those recommendations involved the collaboration of a core network of 1,152 researchers with numerous extension agents and agribusiness personnel. From 2005 to 2015, about 20.9 million farmers in 452 counties adopted enhanced management practices in fields with a total of 37.7 million cumulative hectares over the years. Average yields (maize, rice and wheat) increased by 10.8–11.5%, generating a net grain output of 33 million tonnes (Mt). At the same time, application of nitrogen decreased by 14.7–18.1%, saving 1.2 Mt of nitrogen fertilizers. The increased grain output and decreased nitrogen fertilizer use were equivalent to US$12.2 billion. Estimated reactive nitrogen losses averaged 4.5–4.7 kg nitrogen per Megagram (Mg) with the intervention compared to 6.0–6.4 kg nitrogen per Mg without. Greenhouse gas emissions were 328 kg, 812 kg and 434 kg CO2 equivalent per Mg of maize, rice and wheat produced, respectively, compared to 422 kg, 941 kg and 549 kg CO2 equivalent per Mg without the intervention. On the basis of a large-scale survey (8.6 million farmer participants) and scenario analyses, we further demonstrate the potential impacts of implementing the enhanced management practices on China’s food security and sustainability outlook.
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.
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.
