Supervisor(s): Ministry of Agriculture Sponsor(s): Chinese Academy of Agricultural Sciences；Chinese Association of Agricultural Science Societies CN：11-1328/S
Scientia Agricultura Sinica, the 1st in Comprehensive Agricultural Science, is supervised by Ministry of Agriculture of PRC, and sponsored by Chinese Academy of Agricultural Sciences; Chinese Association of Agricultural Science Societies. Scientia Agricultura Sinica, launched in 1960, is a leading peer-reviewed and mufti-disciplinary journal and published semi-monthly in Chinese with English title, abstract, figures, tables and references. It aims to publish those papers that are influential and will significantly advance scientific understanding in agriculture fields worldwide. The scope covers Crop Genetics, Breeding, Germplasm Resources; Physiology, Biochemistry, Cultivation, Tillage Plant Protection; Soil & Fertilization, Agro-Ecology & Environment, Bio-energy; Animal Science, Veterinary Science, Agricultural Information Science; Food Science; Agricultural Economics and Management; Agricultural Sustainability.
The journal is included in JST, CA and CSCD.
Editor-in-Chief Wan Jianmin Associate Editor-in-Chief Zou Ruicang Tang HuaJun Wu Kongming Guo YuYuan Geng Xu Sun Tan Executive Editor Lu Wenru
[Objective] Cassava–peanut intercropping is an ecological and efficient planting pattern. The effects of N application and cassava–peanut intercropping on the cassava nutrient accumulation and system nutrient utilization were studied and analyzed to provide a theoretical basis for cassava rational intercropping with peanut and efficient nutrient utilization. [Method] With cassava variety South China 205 and peanut variety Yueyou200 as materials, the experiment was carried out with two N levels (with N application and without N application) and five planting patterns (cassava monocropping, peanut monocropping, cassava intercropping with one row of peanut, cassava intercropping with two rows of peanut and cassava intercropping with three rows of peanut), and the cassava nutrient accumulation and system nutrient utilization in different cassava–peanut intercropping patterns were studied in 2015 and 2016. [Result] The results showed that with the advancement of cassava growth stages, the tuber root N, P, K accumulation and its distribution ratio were increased; the stem N, P, K accumulation and stem N distribution ratio were increased and the stem P, K distribution ratios were increased first and then decreased; the leaf N, P, K accumulation was increased first and then decreased, with the distribution ratios decreased. The changes of N, P, K accumulation of tuber root, stem, leaf and plant in different planting patterns were different at different growth stages and different nitrogen application levels. In the same planting pattern, compared with the treatment without nitrogen application, the N, K requirements for 100 kg pod, N, P, K requirements for 100 kg fresh tuber root, cassava N harvest index, cassava P, K partial factor productivity, K intercropping advantage, total N, P accumulation in system and cassava N, P, K ratio in the system of nitrogen application treatment were increased or increased significantly. However, the peanut N, K utilization efficiencies, peanut total P accumulation, cassava N, K utilization efficiencies, cassava K harvest index, N, P, K land equivalent ratios, peanut N, P, K ratios in system and N intercropping advantage of nitrogen application treatment were decreased or decreased significantly. At the same nitrogen application level, the total N, P accumulation and N, P, K partial factor productivity of peanut intercropped were significantly lower than those of peanut monocropping. The N, P, K partial factor productivity, K utilization efficiency, and P harvest index of cassava intercropped were lower than those of cassava monocropping. With the increase of the peanut rows of intercropping, the peanut N, P, K land equivalent ratioa, peanut N, P, K intercropping advantagea, peanut N, P, K ratioa in system, peanut total N, P, K accumulation and peanut N, P, K partial factor productivity were increased or increased significantly, the cassava N, P, K ratioa in system were decreased. [Conclusion] Compared with the monocropping patterns, the N, P, K partial factor productivity, yields and N, P, K accumulation of single crop in the patterns of cassava intercropping with two rows and three rows of peanut were decreased, but the system total N, P, K accumulation was increased, and showed obvious intercropping advantages, the N, P, K intercropping advantages were from 40.87 to 112.11 kg·hm
−2, 19.37 to 42.67 kg·hm
−2 and 68.29 to 105.62 kg·hm
−2, respectively.
[Objective] Based on the investigation of organic carbon and total nitrogen distribution in aggregates of red paddy soil under different fertilization treatments, in this study, the soil organic carbon mineralization in aggregate fractions was further investigated, and the influence factors of organic carbon mineralization were also analyzed. The research results could help to better understand the mechanisms of influence of fertilization on soil fertility and organic carbon mineralization. [Method] Soil samples were collected from a long-term field experiment conducted in red paddy soil, which included nine fertilization treatments, namely no fertilizer (CK), organic cycling (C), N fertilizer (N), N fertilizer plus organic cycling (NC), N and P fertilizer (NP), N, P and K fertilizer (NPK), N, P and K fertilizer plus organic cycling (NPKC), N and K fertilizer (NK), N, P and K fertilizer plus 1/2 rice straw incorporation (NPKS). Those soil samples were separated into five aggregate-size classes by wet sieving, as > 2 mm, 1–2 mm, 0.25–1 mm, 0.053–0.25 mm, and < 0.053 mm. The dynamics of organic carbon mineralization in aggregates and bulk soils was detected, and the microbial biomass carbon content and invertase activity in aggregate fractions were mearsured. [Result] The mineralization rate of organic carbon in bulk soils and > 1 mm aggregates decreased rapidly during the early stage of incubation, and then decreased gradually and reached a stable state. However, the mineralization rate of organic carbon in < 1 mm classes, especially in 0.053–0.25 mm, showed a lesser decrease during the early stage of incubation and reached stability faster. The cumulative amounts of organic carbon mineralization were the highest in > 2 mm and 1–2 mm aggregates while those were the lowest in 0.053–0.25 mm ones. Compared with CK, P fertilizer application (NP and NPK) and organic manure application (C, NC, and NPKC) increased the cumulative amounts of organic carbon mineralization in aggregates by average 17.0%–62.1% and 25.0%–80.5%, respectively. The aggregates of > 2 mm and 0.25–1 mm contributed the most to cumulative amount of soil organic carbon mineralization, accounting for 21.0%–42.5% and 20.6%–32.7%, respectively. The microbial biomass carbon content and invertase activity were higher in > 0.25 mm macro-aggregates than those in <0.25 mm micro-aggregates. The microbial biomass carbon contents in aggregate fractions under P fertilizer and organic manure application treatments were 73.4%–92.0% and 60.8%–99.6% higher than those in aggregate fractions of CK. The application of P fertilizer and organic manure both significantly increased the invertase activity in > 0.25 mm macro-aggregates compared with CK. The invertase activity in macro-aggregates of NC, which was 46.0%–135.0% higher than those of CK, was the highest among all the treatments. The cumulative amounts of organic carbon mineralization in aggregate fractions were significantly and linearly correlated with the contents of organic carbon, total nitrogen, and microbial biomass carbon, as well as with invertase activity. Yet, the organic carbon content had maximum relationship with the cumulative amount of organic carbon mineralization in aggregates. [Conclusion] Macro-aggregates played the leading role in soil organic carbon mineralization. Organic carbon content was the most important factor affecting organic carbon mineralization in aggregate fractions. The application of P fertilizer and organic manure promoted organic carbon mineralization in aggregates of red paddy soil, being beneficial in enhancing the capacity of soil nutrient supplying.
[Background] The PA protein is an integral component of the influenza virus RNA polymerase complex and plays an important role in the transcription and replication of the viral genome. The yeast two-hybrid system was used in our laboratory to screen for host proteins that interact with PA protein, and one of them was identified to be poly (rC)-binding protein 1 (PCBP1). [Objective] This study investigated the interaction between the PCBP1 protein and influenza virus PA protein and the role of PCBP1 on the replication of influenza virus, which would provide scientific data for the in-depth understanding of the replication regulation mechanism of influenza virus in the host. [Method] In order to verify the interaction between PA protein and PCBP1 protein in yeast system, the bait plasmid pGBKT7-PA and the selected prey plasmid pGADT7-PCBP1 as well as the negative control and positive control were cotransformed into yeast competent cells, respectively, according to the LiAc transformation procedure. The transformed yeasts were then spread on three kinds of auxotrophic medium and incubated at 30 °C for 5–7 days to observe the growth and color of colonies. According to the sequences of PA protein and human PCBP1 protein registered in the GenBank, specific amplification primers were designed to construct eukaryotic recombinant expression plasmids pCAGGS-Flag-PA and pCAGGS-Myc-PCBP1. These two eukaryotic expression plasmids were individually transfected or co-transfected into HEK293T cells. The transfected cells were lysed 48 hours after transfection to harvest the supernatant. A small portion of the supernatant was used as a control, and the rest of supernatant was successively added with the FLAG monoclonal antibody and Protein G agarose beads for the preparation of immunoprecipitates. The protein samples were analyzed by SDS-PAGE and Western blot to detect the interaction between PA protein and PCBP1 protein in mammalian cells. To establish a PCBP1-overexpressing cell line, the pseudovirus was packaged in HEK293T cells by using the lentivirus packaging system pLVX-IRES-ZsGreen1, followed by transduction of A549 cells and ultra-fast flow cytometry sorting. After verification of PCBP1 overexpression by Western blot, the overexpressing cell line was infected with WSN virus at an MOI of 0.01. The supernatants were collected at 24 h and 48 h post infection and virus titers were determined by means of plaque assay on MDCK cells. To downregulate the expression of PCBP1 protein, the specific siRNA targeting PCBP1 was synthesized and transfected into A549 cells. At 48 h post treatment with siRNA, the downregulation of PCBP1 expression was confirmed by Western blot, and the siRNA-treated cells were infected with WSN virus at an MOI of 0.01. The supernatants were harvested at 24 h and 48 h after infection and titrated by plaque assay. [Result] The yeast competent cells co-transformed with bait plasmid pGBKT7-PA and recombinant plasmid pGADT7-PCBP1 could grow on SD/-2, SD/-4, and SD/-4/X/A auxotrophic medium plates and produced blue colonies on SD/-4/X/A plates by breaking down X-α-Gal, which was consistent with the positive control group, indicating that the PA protein interacted with PCBP1 protein in the yeast system. The co-immunoprecipitation experiments showed that PA protein bound PCBP1 protein, indicating that they interacted with each other in mammalian cells. The influenza virus replication titer was decreased in the PCBP1-overexpressing cell line. In contrast, the virus titer was increased in the cells transfected with siRNA targeting PCBP1. Together, these results indicated that PCBP1 protein negatively regulated influenza virus replication. [Conclusion] In this study, we demonstrated that the influenza virus PA protein could interact with PCBP1 protein in yeast and mammalian cells, and found that PCBP1 protein negatively regulated the influenza virus replication.
[Background] The low pathogenic H7N9 viruses (see note 1. 1) that emerged in 2013 in China showed low virulence to poultry and were not virulent to the mammalian model-mice. However, a low-pathogenic H7N9 virus isolated in Hunan in 2015 (HuN/S40726 in abbreviation) showed high virulence in mammalian mice. The reason of the change in the virulence of the virus in mammals might be the alteration of the PB2 E627V mutation of the virus. [Objective] In order to reveal the causes of the viral virulence change and the mechanism of the enhancement of the pathogenicity in mammals, and to provide human H7N9 virus infection and early warning of the increased risks, we conducted this study. [Method]We conducted comparative experiments on mammalian virulence and related gene loci that could lead to changes in viral pathogenicity with the low pathogenic H7N9 virus strain (SH/S1053 in abbreviation) and HuN/S40726 virus strain. We successfully established a reverse genetic operating system of Hu N/S40726 virus and rescued related viruses of r HuN/S40726, r Hu N/S40726-PB2/627E and r Hu N/S40726-PB2/627K. The virulence of the above three mutants against mammals was evaluated by using a mouse infection model, and then the differences in the pathogenicity of the related viruses in mice were analyzed. The polymerase complex expression plasmid system of HuN/S40726 and its mutant plasmids were constructed, whereas the SH/S1053 polymerase complex expression plasmid system were constructed as a background control. The dual-luciferase assay system was used to detect the polymerase activities of different mutants of amino acid 627 of PB2 protein in 293T cells, and the intrinsic mechanism of the virulence of amino acid at position 627 of PB2 protein was further analyzed. [Result] By comparative analysis of mammalian virulence and related gene loci that might cause changes in viral pathogenicity, we speculated that the cause of the change in the virulence of the HuN/S40726 virus in mammals might be in the E627V mutation of the PB2 protein. The results of pathogenicity tests on rescued virus and mutant strains in mice showed that the change of PB2 protein E627V significantly enhanced the virulence of Hu N/S40726 virus in mice. The virus MLD
50 was changed from ≥ 6.5 log
10EID
50 to 3.5 log
10EID
50 and the virulence of the virus was increased by at least 1 000 folds. The results of polymerase activity assay showed that the change of PB2 E627V significantly improved the polymerase activity of Hu N/S40726 virus in mammalian cells both at 33 °C or 37 °C, and it was associated with the pathogenicity of the virus in mice. [Conclusion] The 627 amino acid (V) of PB2 protein determined the high virulence of the HuN/S40726 virus in mice. The alteration of PB2 protein E627V could significantly enhance the polymerase activity of HuN/S40726 virus in mammalian cells, and it was an important factor that caused the HuN/S40726 virus to be highly pathogenic to mammals.
[Objective] Huaimai33 is a new wheat cultivar featuring high yield and wide adaptation, which was derived from the cross between Yannong19 and Zhengmai991. In this study, the genetic contribution rates of the two parent cultivars to Huaimai33 were determined by comparing their agronomic traits and genome composition. [Method] The grain yield, quality traits, and high-molecular-weight glutenin subunit (HMW-GS) composition of Huaimai33 and its parents were evaluated. The parental origins of Huaimai33 chromosomal segments were identified using 625 simple sequence repeat (SSR) markers and the segments were analyzed for their effect on yield and yield-related traits by linking them to known quantitative trait loci (QTLs) reported in previous studies. [Result] The spike number per square meter and 1 000-grain weight of Huaimai33 were between those of Yannong19 and Zhengmai991. In contrast, Huaimai33 showed significantly larger grain number per spike and plot yield than both of its parents. The plant height of Huaimai33 was significantly decreased compared with Yannong19. The HMW-GS composition of Huaimai33 was 1, 17 + 18, and 2 + 12, among which the 1 and 17 + 18 subunits were derived from female parent Yannong19 and the 2 + 12 subunit was derived from the male parent Zhengmai991. The SSR marker analysis showed that the two parents contributed differently to the genome of Huaimai33; that is, 73.9% of the Huaimai33 genome was originated from Yannong19 and 26.1% from Zhengmai991. Therefore, Huaimai33 was highly similar to Yannong19, with the genetic similarity coefficient of 0.78. Furthermore, Yannong19 contributed more to Huaimai33 than Zhengmai991 in subgenomes A (75.1%), B (69.4%), and D (68.7%). This was also the case at the level of individual chromosomes except for 6A. In particular, chromosome 2A in its entirety, and over 90% of chromosomes 1A, 3A, 2B, 3B, and 4B were conferred by Yannong19. Of the Huaimai33 chromosomal segments greater than 5 cM in size, 34 segments came from Yannong19 and only 7 from Zhengmai991. Chromosome 2D contained the most segments from Yannong19 of all chromosomes, whereas 5A held the most from Zhengmai991. Interestingly, Huaimai33 had 38 loci that were absent in both parents, which were distributed on chromosomes 1B, 1D, 2A, 2B, 2D, 3A, 3B, 3D, 4A, 4B, 5A, 5B, 6B, 6D, and 7A. Based on the marker-trait associations identified in previous studies, ten genomic regions in Huaimai33 were associated with the effect on yield and yield-related traits. Of these regions, six were contributed by Yannong19 (on chromosomes 1A, 2D, 3B, 4B, 4D, and 7A), three by Zhengmai991 (on chromosomes 4A and 5A), and the last was Huaimai33 specific (on chromosome 6D). [Conclusion] Defining the genetic components of Huaimai33 showed that the genome fractions of the parent Yannong19 were maintained more frequently than Zhengmai991 during development. The chromosomal segments from different parents on grain yield were found. This would improve our understanding of how to develop elite cultivars and their key agronomical traits through breeding.
[Objective] The growth and extension of
Valsa mali in the xylem of apple branches was an important cause of the occurrence of Valsa canker on pruning wounds and the recurrence of old lesions. The objective of this study was to determine the effect of environmental factors on the growth and extension of
V. mali in the xylem of apple branches and to provide the basis and reference for the epidemic prediction and control of the disease. [Method] By inoculating the pathogen to the pruning wounds of detached Fuji apple branches and detecting the extension distance of
V. mali in the xylem with living bark, the effect of temperature, relative water content, and age of branches on the extension of the pathogen in the xylem of apple branches was tested. By inoculating the pathogen to the pruning wounds of Fuji apple branches
in vitro and
in vivo, the dynamics of annual growth of
V. mali in the xylem was investigated systematically. Through
in vitro culture, the growth rate of
V. mali in medium made of different tissues of apple branches was surveyed. [Result]
V. mali could grow and expand by using the water-soluble nutrients in xylem, and the extension rate of
V. mali in the xylem was significantly larger than that in the cortex of apple branches. In the range of 5 ℃–35 ℃,
V. mali could grow and expand in both xylem and cortex of apple branches, and the optimum temperature was 30 ℃. In the xylem of the branches soaked in the distilled water for 24 h, the extension distance of
V. mali was significantly shorter than that in the un-soaked branches. When the relative water content of the branches was greater than 90%, the growth rate of
V. mali in the xylem was large. However, when the relative water content of the branches was less than 90%, the growth and extension of
V. mali in the xylem were significantly inhibited. The extension rate of
V. mali in the xylem of current-year apple branches was significantly larger than that in the xylem of the two–three-year branches. In the xylem of the branches treated with high temperature, the growth rate of
V. mali was significantly larger than that of the untreated branches.
V. mali could grow normally in the medium made of xylem powder, phloem powder, xylem extract, and phloem extract of apple branches and its growth rate and growth amount were not lower than those in PDA. The number of aerial mycelia in phloem medium was larger than that in xylem medium. Under natural conditions, the growth and extension rate of
V. mali inoculated on pruning wound was mainly affected by temperature. The growth rate of
V. mali in vivo Fuji branches was very small from December to March and relatively large from March to November. [Conclusion]
V. mali can grow by using the water-soluble nutrients in the xylem, and the growth rate in the xylem was significantly larger than that in the cortex of apple branches. The growth rate of
V. mali in xylem was mainly affected by temperature, water content of branches, density of xylem and so on.
