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] The SWEETs (Sugars Will Eventually Be Exported Transporters) are a kind of sugar transporters which are involved in plant biological processes and play key roles in plant responses to various stresses and host-pathogen interaction.
SWEET7a was cloned and its function was analyzed to provide a theoretical foundation for exploring the function of SWEETs during fruit development in plant by constructing the silence and overexpression of
SlSWEET7a. [Method] Using Micro-Tom (
Solanum lycopersicum) as a test material, the 842 bp full-length cDNA of
SlSWEET7a was cloned in fruits. The phylogenetic tree of SWEET proteins from
Arabidopsis was constructed by using MEGA6.0, and the homology of SlSWEET7a protein sequences was analyzed. RT-PCR was performed to analyze the spatiotemporal expression of
SlSWEET7a during fruit development stages. The
SlSWEET7a-silencing vector and -overexpressing vector were constructed and transformed into tomato by
Agrobacterium-mediated genetic transformation. The efficiency of two vectors was examined by the transient expression of
Agrobacterium tumefaciens injection method. The expression of
SWEET7a in T
1 generation transgenic green fruits was studied by quantitative PCR. The changes of sugar composition and content in transgenic fruits and leaves were detected by high performance liquid chromatography. [Result] The bioinformatics analysis of protein sequence showed that the SlSWEET7a consisted of seven transmembrane domains. SlSWEET7a belonged to the Clade Ⅱ of the SWEET family, which was highly homologous to AtSWEET6 and AtSWEET8 in
Arabidopsis thaliana. The analysis of spatiotemporal expression indicated that the
SlSWEET7a expression level was the highest in fruit stalks and vascular bundles at mature green stage, while lower at breaker fruit and red ripping stages. The transient expression of
SWEET7a silencing (S7a) and overexpression (OE7a) vector in tomato fruits was observed. The expression level of
SlSWEET7a in fruit of OE7a was 6 times as high as that of non-injected fruit, which was significantly up-regulated compared with that of the control. However, the expression level of
SlSWEET7a in S7a significantly decreased by 5 times. Ten overexpression lines were obtained by kanamycin resistance screening, and eight overexpression lines were obtained by PCR. Fourteen silencing lines were screened by phosphinothricin and 10 transgenic silence lines were obtained by PCR. The real-time quantitative PCR analysis of the
SWEET7a expression in T
1 generation lines revealed that gene silencing occurred in overexpressed plants. The expression level of
SlSWEET7a in the overexpression transgenic plants was significantly lower than that in wild plants, so did the silencing plants. Those results explained that the overexpressing plants also had the phenomenon of gene silencing. The contents of fructose, glucose, sucrose in leaf and fruit after reduction of
SlSWEET7a expression were higher than that in the wild type. Especially, the sucrose content in leaf significantly increased. This showed that
SlSWEET7a played an important role in the facilitated diffusion of sucrose in cells. [Conclusion] SlSWEET7a plays an important role in regulating the loading of sucrose into the phloem of fruit tissue, the transport and unloading of sucrose in fruit stalks and vascular bundles.
[Objective] Soybean GmbZIP16 protein was screened by analyzing soybean drought transcriptome. The functions of soybean
GmbZIP16 were verified by analyzing the phenotypic characterization of transgenic
GmbZIP16 Arabidopsis thaliana and soybean hairy root complexes. On the basis of experimental result analysis above-mentioned, we could determine that
GmbZIP16 was involved in the drought resistance process. [Method] soybean
GmbZIP16 was found out by analyzing soybean drought transcriptome and cloned by PCR. With soybean cDNA as a template,
GmbZIP16 was then ligated the fragment to pCAMBIA1302 and pCAMBIA3301 expression vectors by in-fusion ligase. The recombinant pCAMBIA1302-GmbZIP16 and pCAMBIA3301-GmbZIP16 vectors were transferred into
Agrobacterium tumefaciens GV3101 and K599 competent cells by liquid nitrogen freeze-melt method, respectively. The transgenic
A. thaliana plants and transgenic soybean hairy root complexes were generated with the
A.
tumefaciens-mediated transformation method. The transgenic
GmbZIP16 A. thaliana plants were identified by semi-quantitative PCR and quantitative real time PCR, which demonstrated
GmbZIP16 could overexpress in transgenic
A. thaliana and transgenic soybean hairy root complex plants. Two-week-old transgenic
A. thaliana and WT plants which grew under normal conditions were transferred into MS0 solid medium supplemented with 6% and 8% PEG for 7 days. The biomass difference between transgenic
A. thaliana and WT plants was investigated and analyzed. The different expression of stress-related genes between
A. thaliana and WT plants was analyzed by qRT-PCR. The transgenic
GmbZIP16 soybean hairy root complexes and control group plants were treated with 25% PEG for seven days, and then the leaf samples of transgenic
GmbZIP16 soybean hairy root complex and control group plants were taken. The proline content, MDA content and chlorophyll content of leaf samples were measured by Multiskan Spectrum Microplate Spectrophotometer. [Result] The
GmbZIP16 gene was isolated by PCR technology. The two transgenic
GmbZIP16 A. thaliana lines were obtained with the
A.
tumefaciens-mediated transformation method. Compared with the WT plants, the transgenic
GmbZIP16 A. thaliana lines had higher biomass (the fresh weight and the root length) and survival rate under drought stress by phenotypic characterization experiment. The expression levels of some relative genes such as
RD29B,
DREB2A, and
P5CS were improved in transgenic
GmbZIP16 A. thaliana, compared with the WT plants. The leaves of transgenic
GmbZIP16 soybean hairy root complex plants had the higher proline and chlorophyll content and a lower MDA content than that of the control group plants under the deal with 25% PEG. [Conclusion] The drought resistance of transgenic
A. thaliana was improved by expressing soybean
GmbZIP16 in
A. thaliana. Overexpression of
GmbZIP16 could enhance the drought resistance of transgenic soybean hairy root complex.
GmbZIP16 could improve the drought resistance of plants mainly by affecting the expression of genes related to stress tolerance.
[Objective] Reasonable fertilization is critical for improving winter oilseed rape (
Brassica napus L.) yield. Rough management of fertilization will cause the nutrient efficiency to decline under current intensive planting management mode, thus affecting rapeseed yield. To provide an optimizing management strategy for the rational fertilizer utilization to enhance nutrient efficiency, yield and nutrient efficiency difference was compared between farmer’s practice (FP) and recommended fertilization (RF) for winter oilseed rapes in the Yangtze River Basin (YRB) in this study. [Method] A total of 535 field experiments were selected in the YRB during 2005–2016, including Sichuan, Guizhou, Hubei, Hunan, Anhui, Jiangsu and Zhejiang provinces, China. Three fertilization treatments,
i.e., no-fertilizer (CK), FP, and RF, were designed. The difference in yield and its distribution characteristics, as well as difference of yield increasing rate, fertilization rates, and partial factor productivity, were compared among the treatments and regions. The difference of fertilizer application rates between RF and FP treatments was calculated, and the reduction of nitrogen (N), phosphorus (P), and potassium (K) fertilizer in YRB was evaluated. [Result] The ranges of winter oilseed rape yield for the CK, FP and RF treatments were 500–1 500 kg·hm
−2, 1 500–3 000 kg·hm
−2, and 2 000–3 000 kg·hm
−2, respectively. For the RF treatment, the contribution rate of the soil indigenous fertility supply was only 45.1%–49.7%. The rapeseed yield showed the highest in the lower reach, then the middle reach, and the lowest in the upper reach. The average rapeseed yields of FP management in the upper, middle and lower reaches of the YRB were 2 033 kg·hm
−2, 2 182 kg·hm
−2 and 2 542 kg·hm
−2, respectively, and the RF management produced more rapeseed (16.7%, 16.5%, and 13.9%, on average) than the FP in 77.5%–94.9% of the 535 trails. With the increasing of soil indigenous fertility supply, the yield increasing rate showed a decline trend, and RF treatment showed a higher increasing rate than FP at different levels. The average fertilizer application rates of FP were 162.5–239.5 kg N·hm
−2, 58.6–82.0 kg P
2O
5·hm
−2 and 45.5–60.8 kg K
2O·hm
−2, and the values were 162.2–233.6 kg N·hm
−2, 67.2–94.1 kg P
2O
5·hm
−2 and 73.6–108.5 kg K
2O·hm
−2 for RF treatment. There was no significant difference in the N fertilizer application rates under the two treatments, and the P and K fertilizer application rates were lower under the FP treatment than the RF treatment. Compared with RF, 45.6% and 25.6% of the 535 experiments could reduce the N and P fertilizer application rates, respectively. However, only 13.2% of the experiments could lower the K fertilizer application rate. Meanwhile, 37.8%, 60.0%, and 75.9% of the trails needed more N, P and K fertilizers in the YRB, respectively. Fertilizer application rates were more appropriate in the lower reaches as compared with the other two regions, in which 25.0%, 22.8%, and 17.1% of the 535 trails had the optimum N, P, and K application rates, respectively. The average partial factor productivities of N (PFP
N), P (PFP
P), and K (PFP
K) for FP were 11.1–14.2 kg·kg
−1, 28.6–45.8 kg·kg
−1, and 38.3–47.6 kg·kg
−1, respectively. Although the PFP
N in the RF treatment was 12.9%–15.9% higher than that in the FP treatment across the regions, the values were still lower as compared with other developed countries. Meanwhile, the PFP
P and PFP
K of RF were respectively 6.9% and 19.6% lower than those of the FP treatments, indicating that current recommended fertilizer application rate also had a potential for reduction. [Conclusion] Recommended fertilization management could significantly improve rapeseed yield as compared with farmer’s practice, and the fertilizer application rates of FP had a larger adjustment space.
[Objective] To identify the synergy effects of different mulching patterns on soil water and temperature for improving maize (
Zea mays L.) productivity sustainably, and to provide a theoretical evidence for establishing efficient and environmentally friendly mulching patterns in semi-arid areas of Loess Plateau. [Method] A 3-year field experiment with four mulching patterns during the whole season was carried out in the experiment area: full amount plastic film (PM), degradable film mulching (BM), ridge and furrow planting with plastic film mulched on the ridges (RH), and straw mulching (SM), and conventional flat planting without mulching (CT) was used as the control. Then, the effects of different mulching patterns on soil water and temperature spatiotemporal dynamic variation and utilization characters were also studied thoroughly. [Result] The results showed that mulching during the whole season significantly inhibited the invalid evaporation of soil during the fallow season and improved the potential precipitation use efficiency (PPE). With PM, BM, RH and SM, the precipitation storage during the fallow season was increased by 53, 51, 32, and 36 mm compared with CT, respectively, and the PPE was increased by 14%, 12%, 11%, and 10%, respectively. Film mulching significantly improved the soil temperature, thereby improved the biomass accumulation rate, and shortened the growth and development process of maize, and the jointing stage and mature stage under PM, BM, and RH advanced by 15, 8, and 7 days, and 17, 7 and 7 days, respectively, compared with CT. PM, BM and RH increased the yield by 52%, 32%, and 27%, improved the accumulated temperature use efficiency (TUE) by 57%, 15%, and 58%, increased the water use efficiency (
WUE) by 31%, 14%, and 26%, increased the precipitation use efficiency (PUE) by 53%, 27%, and 29%, and reduced the water consumption coefficient (WUC) by 33%, 21%, and 22%, respectively, compared with CT. SM increased the soil water storage during the maize growing season, but decreased the soil temperature and presented retarded growth, the jointing stage and mature stage with SM delayed by 4 days and 5 days, respectively, which decreased the yield,
WUE and TUE by 21%, 18%, and 9%, respectively, compared with CT. PM intensified the utilization of soil water, then the WSC under PM decreased by 19, 56 and 86 mm, compared with BM, RH and SM, respectively. The soil water balance under PM was greatly affected by the precipitation amount during the middle and late growth stage of maize. The precipitation amount from July to September during 2015 was reduced by 71 mm compared with the average value during many years, and the soil water storage in the 100–200 cm layer under PM reduced 28 mm compared with CT, and 5.4 mm compared with stable soil water storage, which caused water deficit in the deep soil layer. [Conclusion] PM would be a useful method to improve the efficiency of soil hydrothermal resource utilization and to increase maize yield in semi-arid area of Loess Plateau, which accompanied with risks for maintaining deep soil water balance and stabilizing crop yield in the year with droughts during the middle and late growth stage of maize. BM and RH had weak effects on increasing soil temperature and maize yield compared with PM, whereas they were more beneficial to maintaining the balance of soil water. SM showed significant effects on soil temperature decreasing and yield reduction, which was not recommended in the semi-arid area with low temperature.
[Objective] Chlorophyll is an important pigment in plant photosynthesis. The objective of this study is to investigate the inversion of chlorophyll content using crop spectrum information, so as to provide an important basis for real-time monitoring and diagnosis of crop growth. [Method] Based on the field environment under different nitrogen fertilizer application levels (0, 50% and 100%) of maize, the light and small UAV equipped with consumer level digital camera was used to obtain the RGB image of the test area, and then the soil adjusted vegetation index was used for image segmentation. Fifteen common visible vegetation indexes were extracted based on the images before and after segmentation. Then the correlation between vegetation indexes and SPAD values was analyzed. Besides, single variable regression model, multiple regression model and random forest regression model based on visible vegetation indexes were established to estimate the SPAD values. And then, the indicators of accuracy evaluation, coefficient of determination, root mean square error, mean relative error and
P < 0.01 were used to select the best indicators and the optimal model. [Result] There were significant correlations between VI
plot and VI
plant vegetation indexes and the SPAD value of maize canopy. For example, the correlation coefficients between normalized redness intensity (NRI), normalized pigment chlorophyll ratio index (NPCI), blue red ratio index (BRRI) and SPAD value of VI
plant were above 0.77. The univariate regression models were built, which took NRI, NPCI, BRRI and DVI as the independent variables and the measured SPAD as dependent variable, including linear, exponential, logarithmic, quadratic polynomial and power function models, and among those models, the quadratic polynomial model constructed by the NRI index was the best one with the
R2 of 0.797 6, the RMSE of 4.31, and the MRE of 5.91%. The precision of the model using the random forest regression algorithm was the highest, in which the determining coefficient was 0.868 2, the
RMSE was 3.92, and the
MRE was 4.98%. The multiple regression model had higher accuracy than any single variable regression model, in which the
R2 was 0.819,
RMSE was 4, and
MRE was 5.67%. The six inversion models of SPAD were used to make the distribution map of maize canopy SPAD value, and then the map using random forest regression model had the best result which was the closest to real SPAD distribution with
R2 of 0.824 7,
RMSE of 4.3,
MRE of 5.36%, which could be used as a main method of maize canopy chlorophyll monitoring information. [Conclusion] The results showed that the application of UAV digital imagery in retrieving SPAD of maize was feasible, which also added new means and experience to the application of UAV remote sensing system in agriculture.
[Objective] In a survey for cyst nematodes in Jiangxi Province, China, a cyst nematode population was collected and extracted from soybean roots and rhizosphere soil. The morphological characteristics of this population are different from that of the soybean cyst nematode (
Heterodera glycines). The objective of this study is to research morphological and molecular characteristics and parasitism test of this population, identify their species and parasitism to legume crops, and to provide scientific basis for disease prevention and control. [Method] Soil samples were collected in Wuyuan County, Shangrao City, Jiangxi Province. The cysts were collected by sieving method or dissected from the roots. The 2nd stage juveniles (J2s) and males in soil were extracted by using the shallow disk method. The cysts with typical characteristics were selected to make a slice of the vulva cone, the J2s and males separated by shallow disk method were made into permanent slides. The morphological characteristics of cysts, J2s and males were observed and measured under microscope. For molecular studies, single cyst from soybean roots was picked and then ground to extract the genomic DNA. The ribosomal RNA-ITS region and the D2-D3 expansion segments of 28S large subunit rRNA gene were amplified with universal primers AB28, TW81 and D2A, D3B, respectively. The sequencing results were deposited in the Gen Bank database and compared with nematode sequences using the BLAST homology search program. The closest sequences were selected for phylogenetic analyses. The MEGA software was used to construct the ITS and LUS D2-D3 phylogenetic tree of cyst nematodes using neighbor-joining method. The parasitism of this cyst nematode to 11 legume crops and 40 soybean cultivars was tested by artificial inoculation in greenhouse. [Result] The morphological characteristics of cysts, J2s and males of population in this study agreed with
Heterodera sojae reported in Korea. The sequence from the ITS-r DNA (MG859982) was 99% and 98% identical to those of
H. sojae from Korea (KU160510 and KU160512) and only 81% identical to the soybean cyst nematode (
H. glycines) (KY794762.1). The D2-D3 (MG859981) sequence was 99% identical to
H. sojae from Korea (KU160511). In addition, the analysis of the phylogenetic trees constructed by the ITS and LUS D2-D3 both showed that the Jiangxi population and
H. sojae were grouped in the same clade with a reliability of 100%. The cyst nematode population from Jiangxi was identified as
H. sojae—a new record species in China. The inoculation of 11 legume crops showed that the J2s of
H. sojae could infect 10 crops (soybean, jequirity, cowpea, pea, lentil, mung bean, adzuki bean, sword bean, green beans and alfalfa), but could complete the life cycle only on soybean and jequirity. The soybean cultivars resistant identification test results showed that 19 cultivars of the 40 inoculated soybean cultivars were highly susceptible, 11 cultivars were moderately susceptible, 5 cultivars were moderate resistant and 5 cultivars were highly resistant. [Conclusion] The population of cyst nematode collected on soybean from Jiangxi, China was identified as
H. sojae—a new cyst nematode record in China. The parasitism tests indicated that soybean and jequirity were suitable hosts for
H. sojae, and 30 of the 40 soybean cultivars were susceptible to phenotypic disease of cyst nematodes.
