Expression profiling of soybean genes in response to drought (reproductive stage)
ABSTRACT: Drought-responsive genes in soybean leaves were successfully identified using Affymetrix Soybean Gene 1.0 ST arrays on leaves samples of reproductive-stage soybean plants. R1 soybean plants planted in pots were imposed drought by withholding water for 5 days until the soil moisture content dropped to 5%, and 3rd trifoliates (now at the R2 stage) were collected for expression profiling. Soybean plants were grown in pots. When the plants reached the R1 stage (started flowering), drought treatment was imposed by withholding water. The soil moisture content was monitored during the process until the 5th day of water withholding, when soil moisture content reached 5%. The 3rd trifoliate (counting from shoots), now at the R2 stage, was collected for total RNA extraction, while other 3rd trifoliates of similar chlorophyl index were collected for leaves water content determination to identify the severity of the stress. Total RNA from 3rd trifoliates were used for expression profiling using Affymetrix Soybean Gene 1.0 ST arrays. Four biological repeats per treatment were performed, three biological repeats were chosen for expression profiling.
Project description:Drought-responsive genes in soybean leaves were successfully obtained using soybean gene 1.0 ST array. Leaf samples from the vegetative stage of soybean plants were used. V6 soybean plants planted in the pots were imposed drought by withholding water for 6 days until the soil moisture content drop to 5% and trifolium 4th were collected for expression profiling
Project description:We also used microarray analysis to examine transcriptomic changes under moderate drought, identifying thousends of genes that potentially mediate moderate drought responses in the flower, including genes encoding transcription factors that likely play crucial regulatory roles. Arabidopsis were well-watered until after just bolting (after 24 days growth with the main stem about 1 cm high) when moderate drought treatment was started by withholding water (defined as day 0 for moderate drought treatment). The relative soil moisture content decreased rapidly and, after about 48 hours the relative soil moisture content was near 50% of the soil water-holding capacity (first moderate drough treated sample M3 were collected at day 3 (72 h after withholding water)). The soil water condition was maintained by daily watering until almost all the fruits were mature and ready to harvest (about 50 days). For well-watered (control) plants, 90% of the soil water-holding capacity was maintained until tissue harvest or after seed maturation (pots were weighed and watered twice per day). Unopened floral bud samples were collected at day 0, 3, 4, 5, 10.
Project description:We used microarray analysis to examine transcriptomic changes upon dreb1a under drought, identifying hundreds of genes that potentially function downstream of DREB1A and mediate drought responses in the flower, including genes encoding transcription factors that likely play crucial regulatory roles. DREB1a mutant (CS872453) were well-watered until after just bolting (after 24 days growth with the main stem about 1 cm high) when drought treatment was started by withholding water (defined as day 0 for drought treatment). The relative soil moisture content decreased sharply and, after about 80 hours (defined as day 3 for drought treatment), the relative soil moisture content was near 35% of the soil water-holding capacity. The soil water condition was maintained by daily watering until almost all the fruits were mature and ready to harvest. Unopened flower samples were collected from drought treated plants, at day 3, 4, 5.
Project description:We also used microarray analysis to examine transcriptomic changes under drought, identifying thousands of genes that potentially mediate drought responses in the flower, including genes encoding transcription factors that likely play crucial regulatory roles. Arabidopsis were well-watered until after just bolting (after 24 days growth with the main stem about 1 cm high) when drought treatment was started by withholding water (defined as day 0 for drought treatment). The relative soil moisture content decreased sharply and, after about 80 hours (defined as day 3 for drought treatment), the relative soil moisture content was near 35% of the soil water-holding capacity. The soil water condition was maintained by daily watering until almost all the fruits were mature and ready to harvest (about 50 days). For well-watered (control) plants, 90% of the soil water-holding capacity was maintained until tissue harvest or after seed maturation (pots were weighed and watered twice per day). Unopened flower samples were collected, from both treated and control plants, at day 0, 3, 4, 5, 10.
Project description:We examined the effect of soil microbial communities on plant physiological responses to drought. Bouteloua gracilis seeds were planted in sterilized sand with (inoculated) and without (controls) soil microbial communities. After substantial growth, drought was imposed by completely withholding water. Before soil moisture declined to zero, inoculated plants germinated faster, were significantly taller, and maintained greater soil moisture than controls. The greater soil moisture of the inoculated plants allowed greater photosynthesis but also induced lower tissue drought tolerance (as indicated by turgor loss point) compared to controls. The inoculated plants were more susceptible to severe drought compared to control plants as indicated by significantly lower mean stomatal conductance, as well as marginally significantly greater mean wilting score, for the entire severe drought period after soil moisture declined to zero. Inoculated plants exhibited enhanced growth and photosynthesis and dampened drought stress over short timescales, but also increased susceptibility to drought over long timescales. This work demonstrates (1) an unexpected insight that microbes can have positive initial effects on plant performance, but negative impacts on plant performance during severe drought, and (2) that microbially altered effects on plant function during well-watered and moderate drought conditions can influence plant function under subsequent severe drought.
Project description:Six months-old seminal plants of 36 cacao genotypes grown under greenhouse conditions were subjected to two soil water regimes (control and drought) to assess, the effects of water deficit on growth, chemical composition and oxidative stress. In the control, soil moisture was maintained near field capacity with leaf water potentials (?WL) ranging from -0.1 to -0.5 MPa. In the drought treatment, the soil moisture was reduced gradually by withholding additional water until ?WL reached values of between -2.0 to -2.5 MPa. The tolerant genotypes PS-1319, MO-20 and MA-15 recorded significant increases in guaiacol peroxidase activity reflecting a more efficient antioxidant metabolism. In relation to drought tolerance, the most important variables in the distinguishing contrasting groups were: total leaf area per plant; leaf, stem and total dry biomass; relative growth rate; plant shoot biomass and leaf content of N, Ca, and Mg. From the results of these analyses, six genotypes were selected with contrasting characteristics for tolerance to soil water deficit [CC-40, C. SUL-4 and SIC-2 (non-tolerant) and MA-15, MO-20, and PA-13 (tolerant)] for further assessment of the expression of genes NCED5, PP2C, psbA and psbO to water deficit. Increased expression of NCED5, PP2C, psbA and psbO genes were found for non-tolerant genotypes, while in the majority of tolerant genotypes there was repression of these genes, with the exception of PA-13 that showed an increased expression of psbA. Mutivariate analysis showed that growth variables, leaf and total dry biomass, relative growth rate as well as Mg content of the leaves were the most important factor in the classification of the genotypes as tolerant, moderately tolerant and sensitive to water deficit. Therefore these variables are reliable plant traits in the selection of plants tolerant to drought.
Project description:To dissect the molecular mechanisms underlying drought tolerance (DT) in rice, transcriptome differences of a DT introgression line H471, the DT donor P28 and the drought sensitive recurrent parent HHZ under drought stress were investigated using deep transcriptome sequencing. Results revealed a differential constitutive gene expression prior to stress and distinct global transcriptome reprogramming among three genotypes under time-series drought stress, consistent with their differential genotypes and DT phenotypes. DT introgression line H471, the DT donor P28 and the drought sensitive recurrent parent HHZ under drought stress were investigated using deep transcriptome sequencing.The drought stress treatment was started by withholding water at the tillering stage. The days were counted after the AWC in the soil reached 20% to allow drought measurements at precisely determined intervals, and the soil water content reached 15%, 10% and 7.5% after 1d, 3d and 4d drought treatment, respectively.Three top leaves for each sample were harvested for each genotype under 1d and 3d drought stress and control conditions. All samples were immediately frozen in liquid nitrogen and stored at -80C and then for transcriptome sequencing.
Project description:Effects of environmental stressors on the parent may be transmitted to the F1 generation of plants that support global food, oil, and energy production for humans and animals. This study was conducted to determine if the effects of drought stress on parental soybean plants are transmitted to the F1 generation. The germination and seedling vigor of F1 soybean whose maternal parents, Asgrow AG5332 and Progeny P5333RY, were exposed to soil moisture stress, that is, 100, 80, 60, 40, and 20% replacement of evapotranspiration (ET) during reproductive growth, were evaluated under controlled conditions. Pooled over cultivars, effects of soil moisture stress on the parents caused a reduction in the seed germination rate, maximum seed germination, and overall seedling performance in the F1 generation. The effect of soil moisture stress on the parent environment induced seed quality that carried on the F1 generation seed gemination and seedling traits under optimum conditions and further exasperated when exposed to increasing levels of drought stress. Results indicate that seed weight and storage reserve are key factors positively associated with germination traits and seedling growth. Our data confirm that the effects of soil moisture stress on soybean are transferable, causing reduced germination, seedling vigor, and seed quality in the F1 generation. Therefore, optimal water supply during soybean seed formation period may be beneficial for seed producers in terms of optimizing seed quality and vigor characteristics of commodity seed.
Project description:This SuperSeries is composed of the following subset Series: GSE29663: Expression profiling of soybean genes in response to drought (vegetative stage) GSE40604: Expression profiling of soybean genes in response to drought (reproductive stage) Refer to individual Series
Project description:Arbuscular mycorrhizal fungi (AMF) proliferate in soil pores, on the surface of soil particles and affect soil structure. Although modifications in substrate moisture retention depend on structure and could influence plant water extraction, mycorrhizal impacts on water retention and hydraulic conductivity were rarely quantified. Hence, we asked whether inoculation with AMF affects substrate water retention, water transport properties and at which drought intensity those factors become limiting for plant transpiration. Solanum lycopersicum plants were set up in the glasshouse, inoculated or not with Funneliformis mosseae, and grown for 35 days under ample water supply. After mycorrhizal establishment, we harvested three sets of plants, one before (36 days after inoculation) and the second (day 42) and third (day 47) within a sequential drying episode. Sampling cores were introduced into pots before planting. After harvest, moisture retention and substrate conductivity properties were assessed and water retention and hydraulic conductivity models were fitted. A root water uptake model was adopted in order to identify the critical substrate moisture that induces soil derived transpiration limitation. Neither substrate porosity nor saturated water contents were affected by inoculation, but both declined after substrates dried. Drying also caused a decline in pot water capacity and hydraulic conductivity. Plant available water contents under wet (pF 1.8-4.2) and dry (pF 2.5-4.2) conditions increased in mycorrhizal substrates and were conserved after drying. Substrate hydraulic conductivity was higher in mycorrhizal pots before and during drought exposure. After withholding water from pots, higher substrate drying rates and lower substrate water potentials were found in mycorrhizal substrates. Mycorrhiza neither affected leaf area nor root weight or length. Consistently with higher substrate drying rates, AMF restored the plant hydraulic status, and increased plant transpiration when soil moisture declined. The water potential at the root surface and the resistance to water flow in the rhizosphere were restored in mycorrhizal pots although the bulk substrate dried more. Finally, substrates colonized by AMF can be more desiccated before substrate water flux quantitatively limits transpiration. This is most pronounced under high transpiration demands and complies with a difference of over 1,000 hPa in substrate water potential.