Project description:Rice reproductive development is highly sensitive to high temperature stress. In rice flowering occurs over a period of at least 5 days. Heat stress alters the global gene expression dynamics in panicle especially during pollen development, anthesis and grain filling. Some of the rice genotypes like Nagina 22 show better spikelet fertility and grain filling compared to high yielding and popular rice cultivars like IR 64. We carried out microarray analysis of 8 days heat stressed panicles of Nagina22, heat and drought tolerant aus rice cultivar and IR64, a heat susceptible indica genotype along with unstressed samples of Nagina22 and IR64 so as to understand the transcriptome dynamics in these two genotypes under heat stress and to identify the genes important for governing heat stress tolerance in rice.
Project description:A heat and drought tolerant rice cultivar (N22) was grown in the field under control and drought conditions during the dry season in 2013. Drought was applied during early grain filling and resulted in simultaneous heat stress, leading to reduced grain yield and quality. Total RNA was extracted from developing seeds under stress and control (fully flooded) conditions and RNA-seq analysis was performed. These samples are a part of a bigger experiment analysing the responses of three contrasting rice cultivars (N22, Dular, Anjali) to combined heat and drought stress including different organs (developing seeds, flag leaves, flowering spikelets) and developmental stages (early grain filling, flowering) at the transcriptomic level.
Project description:Rice is susceptible to both heat and drought stress, in particular during flowering and grain filling, when both grain yield and quality may be severely compromised. However, under field conditions, these two stresses rarely occur separately. Under well-watered conditions, plants avoid heat stress by transpirational cooling, while this is not possible under drought conditions. Although investigating combined heat and drought stress is clearly more agronomically relevant than analyzing the effects of the single stresses, only a few studies of this stress combination, in particular under field conditions, have been published. Furthermore, little is known about how plants respond during recovery from drought stress, which also determines plant survival. To address these knowledge gaps, three rice cultivars differing in heat and drought tolerance were grown in the field under control and drought conditions in three consecutive years. Drought was applied either during flowering or during early grain filling, resulting in simultaneous heat stress, leading to reduced grain yield and quality. Analysis by gas chromatography-mass spectrometry (GC-MS) showed distinct metabolic profiles for the three investigated organs (flag leaves, flowering spikelets, developing seeds). The metabolic responses of the plants also strongly differed between cultivars and organs, and between stress and rewatering conditions. Correlation analysis identified potential metabolic markers for grain yield and quality under combined heat and drought stress from stress- and rewatering-regulated metabolites and from metabolites with constitutive differences between the cultivars. These results show that GC-MS can resolve metabolic responses to combined heat and drought stress and subsequent rewatering in different organs of field-grown rice. The metabolite profiles can be used to identify potential marker metabolites for yield stability and grain quality that are expected to improve breeding efforts towards climate change resilient rice.
Project description:We used the Structure-seq2 protocol and applied it to 14-day-old rice (Oryza sativa) shoot tissue for genome-wide RNA structure probing to investigate the effect of heat stress on the RNA structurome.
Project description:To better understand the mechanisms that regulate the heat stress response in rice, we conducted a comparative analysis of transcriptome profile in panicles from two rice lines, heat-tolerant line 252 (HTL252) and heat-susceptible line 082 (HSL082) using rice Affymetrix GeneChip. In HTL252 panicles, 1538 differentially expressed genes (DEGs) genes with at least four-fold expression changes compared with the control under heat treatment were considered heat-responsive (HR). Of these DEGs, 522 genes were up-regulated while 1016 genes were repressed. Among DEGs in HSL082, 496 genes were induced and 1707 genes were repressed. Out of the 370 common DEGs found between HTL252 and HSL082, 129 genes were induced and 241 genes were repressed.
Project description:Floral organs are extremely sensitive to stress during anthesis and lead to severe yield loss. Rice anthers and pollinated pistils of two cultivars with contrasting tolerance to heat and drought stress under variable conditions, including control, heat, combined heat and drought stress, were used to explore gene expression pattern in male and female reproductive organs during anthesis under control and stress conditions. More gene regulation was induced by combined drought and heat stress than heat in anthers of both cultivars. N22 showed less regulation under combined stress than Moroberekan. The overlap of regulated genes between two cultivars was rather low, indicated the distinct molecular stress responses. We used whole genome microarrays to explore gene expression pattern and molecular mechanisms in male and female reproductive organs during anthesis under control and stress conditions in two rice cultivars, sought to identify the key transcripts that play roles in inducing heat and drought tolerance during reproduction in rice.
Project description:High temperature markedly reduces the yields and quality of rice grains. To identify the mechanisms underlying heat stress-induced responses in rice grains, proteomic technique was used. Khao Dawk Mali 105 rice grains at the milky, doughy, and mature stages of development after flowering were treated at 40 °C for 3 days. Aromatic compounds were decreased in rice grains under heat stress. The protein abundance involved in glycolysis and tricarboxylic acid cycle, including glyceraldehyde 3-phosphate dehydrogenase and citrate synthase, was changed in milky and doughy grains after heat treatment; however, no changes in mature grains. The abundance involved in amino acid metabolism was increased in doughy grains, but decreased in milky grains. In addition, the abundance involved in starch and sucrose metabolism, such as starch synthase, ADP-glucose pyrophosphorylase, granule-bound starch synthase, and alpha amylase, was decreased in milky grains, but increased in doughy grains. A number of redox homeostasis-related proteins, such as ascorbate peroxidase and peroxiredoxin, were increased in developing rice grains treated with heat stress. These results suggest that in response to heat stress, the abundance of numerous proteins involved in redox homeostasis and carbohydrate biosynthetic pathways may play a major role in the development of KDML105 rice grains.
Project description:In rice (Oryza sativa L.), chilling-induced male sterility increased when plants experienced low water temperature (Tw, 18 °C for 14 days) before panicle initiation. The number of mature pollen grains after chilling at the booting stage (12 °C for 5 days) was only approximately 45% of total pollen grains in low-Tw plants, whereas it was approximately 71% in normal-Tw plants (Tw not controlled; approximately 23 °C under air temperature of 26 °C/21 °C, day/night). Microarray and quantitative PCR analyses showed that many stress-responsive genes (including OsFKBP65 and genes encoding a large heat shock protein OsHSP90.1, heat-stress transcription factors, and many small heat shock proteins) were strongly up-regulated by chilling in normal-Tw spikelets, but were not or rather down-regulated by chilling in low Tw spikelets. OsAPX2 and genes encoding some other antioxidative enzymes were also significantly down-regulated by low Tw in the chilled spikelets. In low-Tw plants, lipid peroxidation products (malondialdehyde equivalents) were significantly increased in the spikelets after chilling, and ascorbate peroxidase activity in the chilled spikelets was significantly lower than that in normal-Tw plants. Our data suggest that an OsFKBP65-related chilling response, which protects proteins from oxidative damage, is indispensable for chilling tolerance but is lost in low-Tw spikelets.
Project description:Transcriptional profiles were compared between vector control and DPB3-1-overexpressing rice plants under control and heat stress conditions. Transcriptional changes of the vector control plants in response to heat stress were also studied.
Project description:Heat stress is a common stress for plants. Long heat stress can triger a series of biological responses. RNA-seq is a useful method to profile RNA dynamics in creatures. Here we profiles the RNA dynamics in heat stressed Arabidopsis. These data will help us understanding the stress response mechanism in plants.