Sugar Transporter GmSWEET38 Controls Nodule Development and Seed Yield in Soybean.

The sugar transporter GmSWEET48 impacts seed yield and composition of soybean.

Cellular sugar status is essentially maintained during normal growth conditions but is impacted negatively during various environmental perturbations. Drought presents one such unfavorable environmental cue that hampers the photosynthetic fixation of carbon into sugars and affects their transport by lowering the cellular osmotic potential. The transport of cellular sugar is facilitated by a specific set of proteins known as sugar transporters. These transporter proteins are the key determinant of influx/ efflux of various sugars and their metabolite intermediates that support the plant growth and developmental process. Abiotic stress and especially drought stress-mediated injury results in reprogramming of sugar distribution across the cellular and subcellular compartments. Here, we have reviewed the imperative role of sugar accumulation, signaling, and transport under typical and atypical stressful environments. We have discussed the physiological effects of drought on sugar accumulation and transport through different transporter proteins involved in monosaccharide and disaccharide sugar transport. Further, we have illustrated sugar-mediated signaling and regulation of sugar transporter proteins along with the overall crosstalk of this signaling with the phytohormone module of abiotic stress response under osmotic stress. Overall, the present review highlights the critical role of sugar transport, distribution and signaling in plants under drought stress conditions.

Early fruit development is critical for determining crop yield. Cell wall invertase (CWIN) and sugar transporters both play important roles in carbon allocation and plant development. However, there is little information about the relationship between CWIN and those functionally related sugar transporters during fruit development. By using transgenic tomato with an elevated CWIN activity, we investigated how an increase in CWIN activity may regulate the expression of sugar transporter genes during fruit development. Our analyses indicate that CWIN activity may be under tight regulation by multiple regulators, including two invertase inhibitors (INVINHs) and one defective CWIN (deCWIN) in tomato ovaries prior to anthesis. Among the sugar transporters, expression of SlSWEET12c for sucrose efflux and SlHT2 for hexose uptake was enhanced by the elevated CWIN activity at 10 and 15 days after anthesis of tomato fruit development, respectively. The findings show that some specific sugars will eventually be exported transporters (SWEETs) and hexose transporters (HTs) respond to elevate CWIN activity probably to promote rapid fruit expansion when sucrose efflux from phloem and hexose uptake by parenchyma cell are in high demand. The analyses provide new leads for improving crop yield by manipulating CWIN-responsive sugar transporters, together with CWIN itself, to enhance fruit development and sugar accumulation.

Microrna Regulation of Nodule Zone-Specific Gene Expression In Soybean

Crop rotation offers several advantages to improve farmers' systems worldwide. The positive attributes of rotations are usually dependent upon crop choices, cropping sequence, soil fertility management, and weather factors. Of these, weather is most uncontrollable, but its effects can be partially manipulated through management. This study presents information on how weather affected cropping systems in a 12-yr span. The study also illustrates the use of indices of weather (composite) variables to predict yields. The composite variables are three biological windows (BW) and a standardized precipitation index (SPI). Biological windows based on soil temperature and soil moisture indicate the number of days favorable for or detrimental to crop growth. Biological window 2 (temperature > 41°F+moist soil) in combination with May temperature explained more than 80% of the variability in corn (Zea mays) and soybean (Glycine max) yields. August temperature negatively affected corn and soybean yields, especially in continuous monocrops. Preseason 9-mo SPI (September-May) explained up to 50% of the subsequent season's corn yields, and this information could influence crop choice. Overall, yields in rotations were higher than in continuous monocropping systems. Nitrogen fertilization increased cereal yields more in continuous monocropping than in rotations with legumes. Corn and soybean appeared more sensitive to soil moisture and temperature variability (P 0.05). Risk as measured by standard deviation in yields or incomes did not differ significantly among systems.

Relationship of soil microbial biomass and activity with fertilization practice and crop yield of three ultisols

SUMMARYCrop production in the Northeast Farming Region of China (NFR) is affected considerably by variation in climatic conditions. Data on crop yield and weather conditions from a number of agro-meteorological stations in NFR were used in a mixed linear model to evaluate the impacts of climatic variables on the yield of maize (Zea mays L.), rice (Oryza sativa L.), soybean (Glycine max L. Merr.) and spring wheat (Triticum aestivum L.) in different crop growth phases. The crop growing season was divided into three growth phases based on the average crop phenological dates from records covering 1981 and 2010 at each station, comprising pre-flowering (from sowing to just prior to flowering), flowering (20 days around flowering) and post-flowering (10 days after flowering to maturity). The climatic variables were mean minimum temperature, thermal time (which is used to indicate changes in the length of growth cycles), average daily solar radiation, accumulated precipitation, aridity index (which is used to assess drought stress) and heat degree-days index (HDD) (which is used to indicate heat stress) were calculated for each growth phase and year. Over the 1961–2010 period, the minimum temperature increased significantly in each crop growth phase, the thermal time increased significantly in the pre-flowering phase of each crop and in the post-flowering phases of maize, rice and soybean, and HDD increased significantly in the pre-flowering phase of soybean and wheat. Average solar radiation decreased significantly in the pre-flowering phase of all four crops and in the flowering phase of soybean and wheat. Precipitation increased during the pre-flowering phase leading to less aridity, whereas reduced precipitation in the flowering and post-flowering phases enhanced aridity. Statistical analyses indicated that higher minimum temperature was beneficial for maize, rice and soybean yields, whereas increased temperature reduced wheat yield. Higher solar radiation in the pre-flowering phase was beneficial for maize yield, in the post-flowering phase for wheat yield, whereas higher solar radiation in the flowering phase reduced rice yield. Increased aridity in the pre-flowering and flowering phases severely reduced maize yield, higher aridity in the flowering and post-flowering phases reduced rice yield, and aridity in all growth phases reduced soybean and wheat yields. Higher HDD in all growth phases reduced maize and soybean yield and HDD in the pre-flowering phase reduced rice yield. Such effects suggest that projected future climate change may have marked effects on crop yield through effects of several climatic variables, calling for adaptation measures such as breeding and changes in crop, soil and agricultural water management.

Soybean (Glycine max) seed is primarily composed of a mature embryo that provides a major source of protein and oil for humans and other animals. Early in development, the tiny embryos grow rapidly and acquire large quantities of sugars from the liquid endosperm of developing seeds. An insufficient supply of nutrients from the endosperm to the embryo results in severe seed abortion and yield reduction. Hence, an understanding of the molecular basis and regulation of assimilate partitioning involved in early embryo development is important for improving soybean seed yield and quality. Here, we used expression profiling analysis to show that two paralogous sugar transporter genes from the SWEET (Sugars Will Eventually be Exported Transporter) family, GmSWEET15a and GmSWEET15b, were highly expressed in developing soybean seeds. In situ hybridization and quantitative real-time PCR showed that both genes were mainly expressed in the endosperm at the cotyledon stage. GmSWEET15b showed both efflux and influx activities for sucrose in Xenopus oocytes. In Arabidopsis (Arabidopsis thaliana), knockout of three AtSWEET alleles is required to see a defective, but not lethal, embryo phenotype, whereas knockout of both GmSWEET15 genes in soybean caused retarded embryo development and endosperm persistence, resulting in severe seed abortion. In addition, the embryo sugar content of the soybean knockout mutants was greatly reduced. These results demonstrate that the plasma membrane sugar transporter, GmSWEET15, is essential for embryo development in soybean by mediating Suc export from the endosperm to the embryo early in seed development.

Nodulation, nodule development and senescence directly affects nitrogen fixation efficiency, and previous studies have shown that inhibition of some cysteine proteases delay nodule senescence, so their nature inhibitors, cystatin genes, are very important in nodulation, nodule development, and senescence. Although several cystatins are actively transcribed in soybean nodules, their exact roles and functional diversities in legume have not been well explored in genome-wide survey studies. In this report, we performed a genome-wide survey of cystatin family genes to explore their relationship to nodulation and nodule development in soybean and identified 20 cystatin genes that encode peptides with 97–245 amino acid residues, different isoelectric points (pI) and structure characteristics, and various putative plant regulatory elements in 3000 bp putative promoter fragments upstream of the 20 soybean cystatins in response to different abiotic/biotic stresses, hormone signals, and symbiosis signals. The expression profiles of these cystatin genes in soybean symbiosis with rhizobium strain Bradyrhizobium japonicum strain 113-2 revealed that 7 cystatin family genes play different roles in nodulation as well as nodule development and senescence. However, these genes were not root nodule symbiosis (RNS)—specific and did not encode special clade cystatin protein with structures related to nodulation and nodule development. Besides, only two of these soybean cystatins were not upregulated in symbiosis after ABA treatment. The functional analysis showed that a candidate gene Glyma.15G227500 (GmCYS16) was likely to play a positive role in soybean nodulation. Besides, evolutionary relationships analysis divided the cystatin genes from Arabidopsis thaliana, Nicotiana tabacum, rice, barley and four legume plants into three groups. Interestingly, Group A cystatins are special in legume plants, but only include one of the above-mentioned 7 cystatin genes related to nodulation and nodule development. Overall, our results provide useful information or clues for our understanding of the functional diversity of legume cystatin family proteins in soybean nodulation and nodule development and for finding nodule-specific cysteine proteases in soybean.

Soybean [Glycine max (L.) Merr.) has been grown recently in central Florida on vegetable‐producing soils which normally lie idle during the hot summer months. The objectives of this study were to determine the K requirements of a cabbage (Brasska oleraceae L. var. capitata)‐sweet corn (Zea mays L.)‐soybean intensively managed cropping sequence on a tile‐drained Immokalee vine sand (sandy, siliceous, hyperthermic Arenic Haplaquods). Eight different K fertilization schedules (varying in rate and timing) were evaluated in a randomized complete block design with six replications over two complete triple‐cropping cycles. Yields of soybean and sweet corn were not increased by addition of 108 lb K2O/acre whenever the previous crop also received K; direct application of 216 lb K2O/acre to cabbage increased cabbage yields regardless of K application to previous sweet corn or soybean crops. Critical soil test K levels below which yields of sweet corn and soybean were increased by a 108 lb K2O/acre application were found to be 25 and 32 ppm K, respectively. Soil test K increased from preplant to soybean bloom without K addition, indicating that K from residues of the previous crop may be an important source of K for the subsequent crop and may account for the low critical values recorded. In 1982, leaf K at bloom and pod‐fill accounted for 50 and 60%, respectively, of the variation in soybean yield. Sidedress K applied at bloom increased leaf K concentration at pod‐fill from 0.65% to 0.92%. Due to the high variability in plant stand and crop growth of the 1983 no‐till soybean crop, no differences in leaf K concentration at late bloom were observed. Increased seed size accounted for an average 23% of the increase in soybean grain yield from the side‐dress K application at soybean bloom. It was concluded that yields of soybean, cabbage, and sweet corn in a multiple cropping sequence depend upon K fertilizer scheduling and can be predicted by soil testing and/or plant analysis.

Core Ideas Subsurface drainage spacing affected corn and soybean production.Narrower subsurface drainage spacing removes excess water from the soil profile in the wettest year.Subsurface drainage depth does not affect corn and soybean production in a Fargo clay soil. Drainage design recommendations for the poorly‐drained, frigid clay soils continue to evolve in the Red River Valley of the North (RRVN). The objective of this 3‐yr (2015–2017) study was to evaluate subsurface drainage spacing (9, 12, and 15 m) and depth (0.9 and 1.2 m) on corn (Zea mays L.), soybean (Glycine max L.), sugarbeet (Beta vulgaris subsp. vulgaris L.) yield and residual soil nitrate‐nitrogen (NO3–N) contents. Subsurface drain spacing had mixed effects on crop yield. For instance, drain spacing significantly affected corn, soybean, and sugarbeet yield in some, but not all of the 3 yr. The highest corn yield was observed under 9 m spacing and lowest with 15 m spacing for 3‐yr average and 2015 (the wettest year). However, wider spacing (15 m) recorded the highest corn yield during 2017 (the driest year). Similarly, sugarbeet yield was highest with the 15 m subsurface spacing (2017), soybean with 9 m spacing (2015 and 3‐yr average). Drain depth had no effect on corn and soybean yield, except for sugarbeet where the 1.2‐m depth had higher yield. The highest residual soil NO3–N for corn occurred for the narrower drain spacing (9 m), and 12 m spacing for sugarbeet in 2016. These data indicated that narrow spaced subsurface drains in poorly‐drained, frigid clay soils may increase corn and soybean yield during wet years, but that wider spacing may be beneficial during relatively dry years along 450 km extent of the RRVN.

Utilizing Machine Learning Framework to Evaluate the Effect of Climate Change on Maize and Soybean Yield

In recent ten years, a perception exists that the agricultural management and crop cultivars have been improved obviously. But the crop yield variation trend due to above reason remain unknown yet. To evaluate the main food crop (maize, soybean and rice) yield trend from 2007 to 2016, the MODIS product (MCD12Q2) was used to extract the mature date of different crops. A two-band variant of the enhanced vegetation index at mature date was applied to establish empirical yield estimation model, coupling with statistical crop yield data. The validation show the estimated yield had accuracy of 90.9%, 91.7% and 83.3%, respectively. The average maize and soybean yield in study area presented increasing trend, but rice yield presented declining. However, maize yield in 22 cities and soybean yield in 19 cities show decreasing trend actually. Through statistical analysis, the crop yield distribution pattern was proved to be almost fixed. Most cities occupies approximate position on the ranking of relevant crop yield. It was demonstrated that some cities, for example Chifeng city, was suitable to develop specific agriculture economy. This paper can be used to give suggestion for agriculture planning and management.

SummaryTwo experiments were run over a 3-year period in the central rainlands of Sudan under two systems of production, rainfed and irrigated, to assess the effects of system of production, inoculation and nitrogen fertilizers on plant and nodule development and grain yield of soya beans. Nodulated plants could fix more than 80 kg N/ha under irrigation whereas under rainfed conditions nodulation was neither effective nor efficient. Soya bean was responsive to nitrogen fertilizers under both systems of production giving significant increments in grain yields. Non-nodulating plants with added nitrogen fertilizers produced more total dry matter than nodulating plants during the vegetative phase until flowering time. At 2 weeks after flowering total dry-matter production for both types was equal and from then on to maturity nodulating plants outyielded non-nodulating ones in total dry-matter production. In 1979 and 1980 yield of irrigated nodulating soya-bean grain was 0·53 and 1·54 t/ha higher than rainfed yields whereas the difference in grain yields of the non-nodulating soya beans was 0·21 t/ha and zero during the same two seasons, respectively. There was a contrasting inverse relation between the number of nodules and dry weights under the two systems of production. Fewer and heavier nodules were produced under irrigation whereas under rainfed conditions nodulation was profuse and nodules were light. On the evidence available 1–4 g/m length of the granular form of soil implant inoculant (Nitragin), i.e. 16·6·66.4 kg/ha, is to be recommended for irrigated soya-bean production in Sudan.

An experiment was conducted over three consecutive seasons during 1982 and 1983 to evaluate the effects of traffic‐induced compaction on growth and yield of maize, cowpea and soya bean grown in a tropical Alfisol for no‐tillage and ploughed systems. Compaction treatments of no, two and four passes of a 2‐tonne roller were used on the sub‐plots. The roller was 60 cm in diameter, 180 cm long, with a contact area of 0.1729 m2 and was pulled by a 33.6 kW tractor. The four‐pass treatment reduced percentage emergence, plant height, leaf number, leaf area index, and dry matter yield of maize, cowpea and soya bean. These reductions were more marked on ploughed than on no‐till plots. The two‐and four‐pass treatments significantly reduced root growth of maize, cowpea and soya bean in the 0–70 mm depth, but the reduction in root density was greater in ploughed than in no‐tillage. The two‐and four‐pass compaction treatments reduced plant nutrient uptake and grain yield of maize, cowpea and soya bean. The four‐pass treatment reduced maize grain yield by 48% in all seasons under no‐tillage and by 53, 61 and 75% after ploughing in the first, second and third consecutive cropping seasons respectively, compared to the yield of the relevant non‐compacted treatment. Cowpea yield was reduced by 38% in all seasons after no‐tillage and by 39, 50 and 57% after ploughing during the first, second and third consecutive cropping season respectively. The response of soya bean to four‐pass compaction resulted in yield reduction by 50,64 and 25% after no‐tillage and by 47, 48 and 65% after ploughing in the first, second and third consecutive cropping season, respectively. Crop yields were found to be negatively correlated with soil bulk density, penetrometer resistance, and relative compaction, and positively correlated with infiltration rate, soil moisture content and specific volume. Multiple regression equations were also developed between crop yield and soil properties.