The study explored the mechanism of Dan'e-fukang soft extract in treating endometriosis (EMs) through network pharmacology. The main active ingredients of Dan'e-fukang soft extract were analyzed based on the traditional Chinese medicine systems pharmacology database and analysis platform (TCMSP). Drug target genes were mined by PubChem, and differential genes were analyzed based on Gene Expression Omnibus (GEO) database microarrays GSE7305, GSE11691, and GSE12768. A total of 101 differential drug target genes were screened. Gene Ontology (GO) analysis revealed that the 101 differential drug target genes were mainly enriched in the regulation of cell migration, inflammatory response, and cytokine-mediated signaling pathways; among them, factors associated with both inflammatory response and negative regulation of cell migration were allograft inflammatory factor 1 (AIF-1), C-C motif chemokine ligand 2 (CCL2), and Cadherin-1 (CDH1), of which CCL2 was upregulated in all three endometriosis-related GEO datasets. CCL2 was also upregulated in endometriosis patient tissues as well as in ectopic endometrial stromal cells (ESCs). The overexpression of CCL2 in normal ESCs promoted cell proliferation, migration, invasion, and expression levels of inflammatory factors (TNF-α, IL-1β, and IL-6). However, the silencing of CCL2 in ectopic ESCs had the opposite result. Liquiritin was identified as a potential key active monomer of Dan’e-fukang soft extract based on network pharmacology prediction. Liquiritin inhibited CCL2 expression and inhibited proliferation, migration, invasion, and inflammation in ectopic ESCs, while overexpression of CCL2 partially reversed these functions of liquiritin. Liquiritin inhibits ectopic ESC proliferation, migration, and inflammation by inhibiting CCL2 and thereby alleviating endometriosis.

BACKGROUND:The DExD/H-box (DDX) helicase family plays critical roles in RNA metabolism and has been implicated in tumorigenesis. However, the pan-cancer activities and prognostic potential of DDX52, especially in liver hepatocellular carcinoma (LIHC), are largely unknown. METHODS:We comprehensively analyzed DDX52 across pan-cancer using TCGA, GEO, HPA, and SpatialTME databases, assessing its differential expression, prognosis, genetic alterations, Tumor Mutational Burden (TMB), Microsatellite Instability (MSI), and immune microenvironment features. In LIHC, we performed functional enrichment, PPI network, single-cell sequencing, and drug sensitivity analyses. Molecular docking explore potential small-molecule inhibitors of DDX52. Finally, we validated DDX52 expression and function in LIHC. RESULTS:DDX52 mRNA and protein expression were significantly upregulated in multiple malignancies, including LIHC. Elevated DDX52 expression correlated with poor prognosis in LIHC. Genetic analysis revealed frequent copy number variations (CNV) and single-nucleotide variants (SNV) of DDX52, with significant positive correlations between DDX52 expression and both TMB and MSI across numerous cancer types. DDX52 expression was also significantly associated with immune cell infiltration, immune checkpoint molecules. In LIHC, DDX52 was predominantly expressed in B cells, proliferating T cells, malignant cells, and monocytes/macrophages. Functional enrichment analysis indicated DDX52 involvement in metabolic processes, histone modification, cell cycle regulation, and oncogenic signaling pathways. Pharmacologically, high DDX52 expression correlated with reduced drug sensitivity. Experimentally, DDX52 silencing significantly inhibited proliferation, colony formation, migration, and invasion in HepG2 and MHCC-97H cells. CONCLUSIONS:Our integrative analyses and experimental validation suggest that DDX52 is a potential prognostic biomarker and therapeutic target in LIHC. Its associations with immune features and multiple cancer-related pathways provide hypotheses for future mechanistic investigation.

Maize(Zea mays L.) is a monoecious grass species with separate male and female inflorescences which form the tassel and ear, respectively. The mature ear inflorescences usually bear hundreds of grains, so they directly influence maize grain production and yield. Here, we isolated a recessive maize mutant, tasselseed2016(ts2016), which exhibits pleiotropic inflorescence defects and reduced grain yield. These defects include the loss of determinacy and identity in meristems and floral organs, as well as a lack of the lower floret abortion in maize ear, and a smaller grain size. Using map-based cloning and allelic testing, we identified and confirmed the microRNA gene MIR172e as the target gene controlling these related traits. Furthermore, our evidence uncovered a new potential miR172e/ETHYLENE RESPONSIVE ELEMENT BINDING197(EREB197) regulatory module which controls lower floret abortion in maize ear. Transcriptome analysis revealed that the mutation of MIR172e represses multiple biological processes, particularly the flower development and hormone-related pathways in maize ear. We also found that a mutation in the DNA sequence of MIR172e affects RNA transcription, resulting in elongation blockage at the mutant site. Our results reveal the function and molecular mechanism of MIR172e in maize inflorescences and grain yield, and this study deepens our knowledge of maize inflorescence development.

To clarify the response mechanism of exogenous paclobutrazol on drought resistance in Phoebe bournei seedlings,we investigated the effects of spraying different concentrations of paclobutrazol(25,50,100 mg·L-1)on the photosynthetic and antioxidant systems of 2-year-old P.bournei seedlings under drought stress using natural drought method.The results showed that drought stress significantly reduced the photosynthesis and broke the dy-namic balance of antioxidant system in P.bournei seedlings.Spraying with different concentrations of paclobutrazol effectively alleviated the negative impacts of drought stress,and enhanced the defense capability of photosynthetic and antioxidant systems,with the 100 mg·L-1 paclobutrazol treatment being the most effective.Under exogenous 100 mg·L-1 paclobutrazol treatment,the total chlorophyll in leaves increased significantly,with a maximum in-crease of 51.9％.The apparent photosynthetic electron transfer rate,photochemical quenching coefficient and actual photochemical quantum yield were significantly increased,with maximum increase of 67.8％,58.4％,and 59.7％,respectively.The net photosynthetic rate,stomatal conductance and transpiration rate,were enhanced,reaching maximum increase of 65.5％,65.4％,and 68.6％,respectively.In summary,exogenous 100 mg·L-1 paclobutrazol has the strongest ability to enhance drought resistance of P.bournei seedlings by regulating photosyn-thetic and antioxidant systems.

Nitrogen is a major driving force for the improvement of crop yield worldwide but brings detrimental effects on ecosystems. Therefore, enhancing nitrogen use efficiency (NUE) is vital for sustainable agriculture. The nitrate transporter (NRT1/NPF) family associated with nitrogen uptake and utilization is indispensable to the improvement of NUE in crops. As an important food security crop, cassava (Manihot esculenta) produces an acceptable yield in nutrient-deficient soil. Here, we identified and systematically analyzed the NPF gene family in cassava, including phylogenetic relationship, chromosome location, gene duplication, and gene expression in response to different nitrogen supplies. The stem is involved in nitrogen transportation and remobilization. Gene expression analysis revealed that MeNPF5.4 and MeNPF6.2 were specifically expressed in the stem, and have diverse expression in different nitrogen conditions. To facilitate the functional analysis of MeNPF5.4 and MeNPF6.2, we constructed their overexpression (OE) lines in rice. A NO3- flux assay showed that MeNPF5.4 and MeNPF6.2 OE lines exhibited a marked decrease in NO3- efflux and significant NO3- influx compared with WT, which suggests that they might have contributed to the NUE improvement of rice. Notably, overexpressing MeNPF5.4 showed increased grain size, grain number, and grain weight per panicle. More importantly, the MeNPF5.4 OE line contributed to salt tolerance. Nevertheless, an obvious reduction in grain number and grain weight per panicle was detected in the MeNPF6.2 OE line compared with WT. Strikingly, the MeNPF6.2 OE line showed higher salt stress tolerance than WT in LN conditions. Taken together, our results demonstrated that MeNPF5.4 can potentially improve the NUE and salt stress tolerance of rice, which reveals valuable breeding targets to improve crop yield and stress tolerance.

The heat shock transcription factors (HSFs) family is widely present in eukaryotes including plants. Recent studies have indicated that HSF is a multifunctional group of genes involved in plant growth and development, as well as response to abiotic stresses. Here we combined the bioinformatic, molecular biology way to dissect the function of Hsf, specifically HsfB4 in wheat under abiotic stresses. In this study, we identified 78 TaHSF genes in wheat (Triticum aestivum) and analyzed their phylogenetic relationship and expression regulation motifs. Next, the expression profiles of TaHSFs and AtHSFs were analyzed in different tissues as well as in response to abiotic stress. Furthermore, to explore the role of HSFB4 in abiotic stress response, we cloned TaHSFB4-2B from the wheat variety, Chinese Spring. Subcellular localization analysis showed that TaHSFB4-2B was localized in the nucleus. In addition, We observed TaHSFB4-2B was highly expressed in the root and stem, its transcription was induced under long-term heat shock, cold, and salinity stress. Additionally, overexpression of TaHSFB4-2B suppressed seed germination and growth in Arabidopsis with salinity and mannitol treatment. It also modulated the expression of stress-responsive genes, including AtHSP17.8, AtHSP17.6A, AtHSP17.6C, CAT2, and SOS1, under both normal and stress conditions. From these finding, we propose that TaHSFB4-2B act as a negative regulator of abiotic stress response in the plant.

Mercury (Hg) is a heavy metal (HM) that affects crop growth and productivity. In a previous study, we found that application of exogenous abscisic acid (ABA) alleviated growth inhibition in Hg-stressed wheat seedlings. However, the physiological and molecular mechanisms underlying ABA-mediated Hg detoxification remained unclear. In this study, Hg exposure reduced the plant fresh and dry weights and root numbers. Exogenous ABA treatment significantly resumed the plant growth, increased the plant height and weight, and enriched the roots numbers and biomass. The application of ABA enhanced Hg absorption and raised the Hg levels in the roots. In addition, exogenous ABA decreased Hg-induced oxidative damage and significantly brought down the activities of antioxidant enzymes, such as SOD, POD and CAT. Global gene expression patterns in the roots and leaves exposed to HgCl2 and ABA treatments were examined via RNA-Seq. The data showed that genes related to ABA-mediated Hg detoxification were enriched in functions related to cell wall formation. Weighted gene co-expression network analysis (WGCNA) further indicated that the genes implicated in Hg detoxification were related to cell wall synthesis. Under Hg stress, ABA significantly induced expression of the genes encoding cell wall synthesis enzymes, regulated the activity of hydrolase, and increased the concentrations of cellulose and hemicellulose, hence promoting cell wall synthesis. Taken together, these results suggest that exogenous ABA could alleviate Hg toxicity in wheat by promoting cell wall formation and suppressing translocation of Hg from roots to shoots.

Heat stress (HS) seriously restricts the growth and development of plants. When plants are exposed to extreme high temperature, the heat stress response (HSR) is activated to enable plants to survive. Sessile plants have evolved multiple strategies to sense and cope with HS. Previous studies have established that PHYTOCHROME INTERACTING FACTOR 4 (PIF4) acts as a key component in thermomorphogenesis; however, whether PIF4 regulates plant thermotolerance and the molecular mechanism linking this light transcriptional factor and HSR remain unclear. Here, we show that the overexpression of PIF4 indeed provides plants with a stronger basal thermotolerance and greatly improves the survival ability of Arabidopsis under severe HS. Via phylogenetic analysis, we identified two sets (six) of PIF4 homologs in wheat, and the expression patterns of the PIF4 homologs were conservatively induced by heat treatment in both wheat and Arabidopsis. Furthermore, the PIF4 protein was accumulated under heat stress and had an identical expression level. Additionally, we found that the core regulator of HSR, HEAT SHOCK TRANSCRIPTION FACTOR A2 (HSFA2), was highly responsive to light and heat. Followed by promoter analysis and ChIP-qPCR, we further found that PIF4 can bind directly to the G-box motifs of the HSFA2 promoter. Via effector–reporter assays, we found that PIF4 binding could activate HSFA2 gene expression, thereby resulting in the activation of other HS-inducible genes, such as heat shock proteins. Finally, the overexpression of PIF4 led to a stronger basal thermotolerance under non-heat-treatment conditions, thereby resulting in an enhanced tolerance to severe heat stress. Taken together, our findings propose that PIF4 is linked to heat stress signaling by directly binding to the HSFA2 promoter and triggering the HSR at normal temperature conditions to promote the basal thermotolerance. These functions of PIF4 provide a candidate direction for breeding heat-resistant crop cultivars.

Catalases (CATs) are present in almost all living organisms and play important roles in plant development and response to various stresses. However, there is relatively little information on CAT genes in wheat and related Triticeae species. A few studies on CAT family genes in wheat have been reported. In this study, ten CAT proteins (TaCATs) were identified in wheat and classified into three groups based on their phylogenetic features and sequence analysis. The analysis of the structure and motif composition of the TaCAT proteins suggested that a segmental duplication event occurred in the TaCAT gene family. Collinearity relationship analysis among different species showed that there were three orthologous CAT genes in rice and in maize. By analyzing the cis-elements in the promoter regions, we speculated that TaCAT genes expression might be regulated by light, oxygen deficit, methyl jasmonate and abscisic acid, and by transcription factors such as MYB. A Gene Ontology (GO)-based analysis showed that TaCAT proteins may be related to the response to various stresses, are cytoplasm localized, and may function as antioxidant enzymes. RT-qPCR and transcriptome data analyses exhibited distinct expression patterns of TaCAT genes in different tissues and in response to various treatments. In this study, a comprehensive analysis of wheat CAT genes was performed, enriching our knowledge of CAT genes and providing a foundation for further functional analyses of this gene family in wheat.

Nitrogen is one of the most important nutrient elements required for plant growth and development, which is also immensely related to the efficient use of nitrogen by crop plants. Therefore, plants evolved sophisticated mechanisms and anion channels to extract inorganic nitrogen (nitrate) from the soil or nutrient solutions, assimilate, and recycle the organic nitrogen. Hence, developing crop plants with a greater capability of using nitrogen efficiently is the fundamental research objective for attaining better agricultural productivity and environmental sustainability. In this context, an in-depth investigation has been conducted into the cassava slow type anion channels (SLAHs) gene family, including genome-wide expression analysis, phylogenetic relationships with other related organisms, chromosome localization, and functional analysis. A potential and nitrogen-responsive gene of cassava (MeSLAH4) was identified and selected for overexpression (OE) analysis in rice, which increased the grain yield and root growth related performance. The morpho-physiological response of OE lines was better under low nitrogen (0.01 mm NH4NO3) conditions compared to the wild type (WT) and OE lines under normal nitrogen (0.5 mm NH4NO3) conditions. The relative expression of the MeSLAH4 gene was higher (about 80-fold) in the OE line than in the wild type. The accumulation and flux assay showed higher accumulation of NO 3 - and more expansion of root cells and grain dimension of OE lines compared to the wild type plants. The results of this experiment demonstrated that the MeSLAH4 gene may play a vital role in enhancing the efficient use of nitrogen in rice, which could be utilized for high-yielding crop production.

Abstract Nitrogen is a major driving force for the improvement of crop yield worldwide, but brings detrimental effects on ecosystems, thus future agricultural sustainability demands enhanced nitrogen use efficiency (NUE). The nitrate transporter (NRT/NPF) family associated with nitrogen uptake and utilization is indispensable to the improvement of NUE in crops. Because cassava (Manihot esculenta) has high-affinity to absorb nitrate, the NUE of the NPF genes in cassava might be higher than other crops. Here we identified and systematically analyzed the NPF gene family in cassava, including phylogenetic relationship, chromosome location, gene duplication, and gene expression in response to different nitrogen supply. Gene expression analysis revealed that MeNPF5.4 and MeNPF6.2 were specifically expressed in stem, and have diverse expression in different nitrogen conditions. To well study the roles of these two genes, we constructed their overexpression (OE) lines in rice. A NO3− flux assay showed that MeNPF5.4 OE lines exhibited a significant NO3− influx, which suggests that they might have contributed to NUE improvement of rice. Notably, overexpressing MeNPF5.4 not only results in increased grain size and weight but also enhanced tolerance to salt. Compared with MeNPF5.4, MeNPF6.2 OE lines showed higher salt stress tolerance but had smaller grain size. Taken together, our results demonstrated that MeNPF5.4 can potentially improve the NUE and salt stress tolerance of rice, which reveals valuable breeding targets to improve crop yield and stress tolerance.

Nitrogen is a major driving force for the improvement of crop yield worldwide, but brings detrimental effects on ecosystems, thus future agricultural sustainability demands enhanced nitrogen use efficiency (NUE). The nitrate transporter (NRT/NPF) family associated with nitrogen uptake and utilization is indispensable to the improvement of NUE in crops. Because cassava has high-affinity to absorb nitrate, the NUE of the NPF genes in cassava might be higher than other crops. Here we identified and systematically analyzed the NPF gene family in cassava, including phylogenetic relationship, chromosome location, gene duplication, and gene expression in response to different nitrogen supply. Gene expression analysis revealed that MeNPF5.4 and MeNPF6.2 were specifically expressed in stem, and had diverse expression in different nitrogen conditions. To well study the roles of these two genes, we constructed their overexpression (OE) lines in rice. A NO3- flux assay showed that MeNPF5.4 OE lines exhibited a significant NO3- influx, which suggests that they might have contributed to NUE improvement of rice. Notably, overexpressing MeNPF5.4 not only results in increased grain size and weight but also enhanced tolerance to salt. Compared with MeNPF5.4, MeNPF6.2 OE lines showed higher salt stress tolerance but were no significant difference in grain size. Taken together, our results demonstrated that MeNPF5.4 can potentially improve the NUE and salt stress tolerance of rice, which reveals valuable breeding targets to improve crop yield and stress tolerance.

Soil nematode is an essential component of the soil micro-food web and plays an important role in soil nutrient cycling. The biogeographic distribution pattern of the soil nematode community and its main driving factors have attained greater attention in the last few decades. However, previous studies mainly focused on low and middle latitudes, and few studies were conducted in cold and temperate regions at high latitudes. The structure and diversity of soil nematodes along the altitudinal gradient are still unclear, which prevents understanding and comparing the diversity of soil nematodes at different spatial scales. In this study, six altitudes (750, 830, 950, 1100, 1300, and 1420 m) were set in the Oakley Mountain in the cold-temperate zone in China, and Illumina MiSeq sequencing method was used to explore the community composition and structural characteristics of soil nematodes in 0- to 10-cm soil. The diversity of soil nematode community in a high-latitude cold-temperate zone showed a decreasing pattern of monotonicity along the altitudinal gradient. One phylum, 3 classes, 11 orders, and 43 genera were identified; plant–parasites were the dominant trophic groups at each altitude. Altitude was the main factor affecting the diversity of soil nematodes at higher latitudes. Sobs, Chao1, Shannon index, and Faith's phylogenetic diversity all showed a downward trend with the increase in altitude. Soil bulk density, soil temperature, pH, soluble organic carbon, and soluble organic nitrogen were significant factors affecting the altitude distribution of soil nematodes. Soil pH and soluble organic nitrogen were the key factors to explain the changes in the community composition of nematodes.

Elephant grass (Pennisetum purpureum) is a perennial grass in the Poaceae family with high tolerance and one of the best forage plants. Despite its economic importance, the inheritance information of P. purpureum has remained largely unknown. To obtain the whole reference genome, we first conducted a genome survey of P. purpureum. Next-generation sequencing (NGS) was used to perform the de novo whole genome sequencing. As a result, the estimated genome size of elephant grass was 2.01 Gb, with 71.36% repetitive elements. The heterozygosity was 1.02%, which indicates a highly heterozygous genome. The retroelements (9.36%) were the most repetitive elements, followed by DNA transposons (3.66%). In the meantime, 83,706 high-quality genomic simple sequence repeat (SSR) markers, in which the greatest SSR unit length was 3, were developed. Thirty pairs of SSR markers were randomly selected to verify the efficiency and all of them yielded clear amplification products, among which 28 pairs (93.3%) of the primers showed polymorphism. The genome data obtained in this research provided a large amount of gene resources for further investigating Pennisetum species.

Drought is a major abiotic stress that impairs growth and productivity of Italian ryegrass. Comparative analysis of drought responsive proteins will provide insight into molecular mechanism in Lolium multiflorum drought tolerance. Using the iTRAQ-based approach, proteomic changes in tolerant and susceptible lines were examined in response to drought condition. A total of 950 differentially accumulated proteins was found to be involved in carbohydrate metabolism, amino acid metabolism, biosynthesis of secondary metabolites, and signal transduction pathway, such as β-D-xylosidase, β-D-glucan glucohydrolase, glycerate dehydrogenase, Cobalamin-independent methionine synthase, glutamine synthetase 1a, Farnesyl pyrophosphate synthase, diacylglycerol, and inositol 1, 4, 5-trisphosphate, which might contributed to enhance drought tolerance or adaption in Lolium multiflorum. Interestingly, the two specific metabolic pathways, arachidonic acid and inositol phosphate metabolism including differentially accumulated proteins, were observed only in the tolerant lines. Cysteine protease cathepsin B, Cysteine proteinase, lipid transfer protein and Aquaporin were observed as drought-regulated proteins participating in hydrolysis and transmembrane transport. The activities of phospholipid hydroperoxide glutathione peroxidase, peroxiredoxin, dehydroascorbate reductase, peroxisomal ascorbate peroxidase and monodehydroascorbate reductase associated with alleviating the accumulation of reactive oxygen species in stress inducing environments. Our results showed that drought-responsive proteins were closely related to metabolic processes including signal transduction, antioxidant defenses, hydrolysis, and transmembrane transport.

BACKGROUND:Vernalization and the transition from vegetative to reproductive growth involve multiple pathways, vital for controlling floral organ formation and flowering time. However, little transcription information is available about the mechanisms behind environmental adaption and growth regulation. Here, we used high-throughput sequencing to analyze the comprehensive transcriptome of Dactylis glomerata L. during six different growth periods.RESULTS:During vernalization, 4689 differentially expressed genes (DEGs) significantly increased in abundance, while 3841 decreased. Furthermore, 12,967 DEGs were identified during booting stage and flowering stage, including 7750 up-regulated and 5219 down-regulated DEGs. Pathway analysis indicated that transcripts related to circadian rhythm, photoperiod, photosynthesis, flavonoid biosynthesis, starch, and sucrose metabolism changed significantly at different stages. Coexpression and weighted correlation network analysis (WGCNA) analysis linked different stages to transcriptional changes and provided evidence of inner relation modules associated with signal transduction, stress responses, cell division, and hormonal transport.CONCLUSIONS:We found enrichment in transcription factors (TFs) related to WRKY, NAC, AP2/EREBP, AUX/IAA, MADS-BOX, ABI3/VP1, bHLH, and the CCAAT family during vernalization and floral bud development. TFs expression patterns revealed intricate temporal variations, suggesting relatively separate regulatory programs of TF modules. Further study will unlock insights into the ability of the circadian rhythm and photoperiod to regulate vernalization and flowering time in perennial grass.

Postoperative cognitive dysfunction (POCD) is a common complication that presents in the postoperative stage, especially in elderly patients. Despite years of considerable progress, the detailed molecular mechanisms of POCD remain largely unknown. Neuroinflammation has been increasingly pointed out as one of the core mechanisms for the pathogenesis of POCD. However, application of anti-inflammatory drugs failed to show consistent beneficial effect in patients with cognitive decline. Hence, it might be of great importance to identify the inflammatory initiators that are involved in the mediation, amplification and perpetuation of postoperative neuroinflammatory reactions. Extracellular RNAs (exRNAs), released from necrotic cells, were demonstrated to initiate the inflammatory responses in various pathological conditions. Recent study has suggested neuroprotective and edema protective effects of ribonuclease (RNase), the counterpart of RNA, in acute stroke. It was theorized that RNase acted against endogenous RNA that was released from tissue damage. Similarly, we have observed significant attenuation of cognitive impairment by RNase in aged mice after unilateral nephrectomy. Damping the systemic initiators at early stages may help to prevent the chain reaction that triggers the central inflammatory or apoptotic response. Therefore, we propose the hypothesis that exRNAs released upon stress, through acting on the peripheral and/or central receptors, may trigger a damaging cascade leading to the development of POCD. Undoubtedly, further study is urgently needed to elucidated the exact signaling mechanisms and confirm the proposed hypothesis.

Drought is a major environmental stress that limits growth and development of cool-season annual grasses. Drought transcriptional profiles of resistant and susceptible lines were studied to understand the molecular mechanisms of drought tolerance in annual ryegrass (Lolium multiflorum L.). A total of 4718 genes exhibited significantly differential expression in two L. multiflorum lines. Additionally, up-regulated genes associated with drought response in the resistant lines were compared with susceptible lines. Gene ontology enrichment and pathway analyses revealed that genes partially encoding drought-responsive proteins as key regulators were significantly involved in carbon metabolism, lipid metabolism, and signal transduction. Comparable gene expression was used to identify the genes that contribute to the high drought tolerance in resistant lines of annual ryegrass. Moreover, we proposed the hypothesis that short-term drought have a beneficial effect on oxidation stress, which may be ascribed to a direct effect on the drought tolerance of annual ryegrass. Evidence suggests that some of the genes encoding antioxidants (HPTs, GGT, AP, 6-PGD, and G6PDH) function as antioxidant in lipid metabolism and signal transduction pathways, which have indispensable and promoting roles in drought resistance. This study provides the first transcriptome data on the induction of drought-related gene expression in annual ryegrass, especially via modulation of metabolic homeostasis, signal transduction, and antioxidant defenses to improve drought tolerance response to short-term drought stress.

Nitrogen plays an important role in promoting plant growth and development.The purpose of this study was to investigate the characteristics of dry matter production and nitrogen accumulation for rice genotypes with different nitrogen use efficiencies(NUE)and to analyse the relationship between grain yield and NUE.A soil culture pot experiment was carried out at Sichuan Agricultural University,Sichuan province,China in 2009.The grain yield of high NUE genotypes was 1.74-2.37 times higher than that of low NUE genotypes,while NUE of high NUE genotypes was 23.97%-70.55% higher than that of low NUE genotypes.Dry matter weight of high NUE genotypes was significantly higher than that of low NUE genotypes at all growth stages,which were 1.12,1.49 and 5.85 times higher than that of low NUE genotypes at tillering-to-jointing stage,jointing-to-heading stage and heading-to-maturity stages respectively.The peak dry matter weight of high NUE genotypes occurred at heading-to-maturity stage,while that of low NUE genotypes occurring at tillering-to-jointing stage.Nitrogen accumulation rate of high NUE genotypes increased faster in the early stages,and achieved a maximum 30-50 dafter transplanting,then slowed down.Maximum nitrogen accumulation rates of Meigugu,IR31892-100-3-3-3and IRIT216 were 11.32,12.36 and 15.83mg/(d·plant),which were respectively 1.22,1.33 and 1.70 times higher than Jiazao 935;and,respectively,1.56,1.70 and 2.18 times higher than IR32429 with low NUE respectively.High NUE genotypes can maintain higher rates of nitrogen accumulation for longer,with an average duration of 49 dfrom tillering to heading stages.Low NUE genotypes had a development period 12 dshorter than that of high NUE genotypes.Dry matter weight and nitrogen accumulation at the heading-to-maturity stage were associated,respectively,with 62.65% and 47.42% differernce in rice yield,with 14.51% and 8.77% variation in nitrogen grain production efficiency,and 22.14% and15.90% variation,respectively,in nitrogen harvest index.In summary,rice dry matter accumulation and nitrogen accumulation were closely related to yield and NUE at the heading-to-maturity stage.Tillering-to-heading is a critical stage for rice nitrogen nutrition management.

The objective of this study was to establish an efficient and reproducible in vitro plant regeneration for Citrullus lanatus cv. Zaojia. To achieve optimal conditions for adventitious shoot induction, five explants (entire cotyledons, distal cotyledons, proximal cotyledons, cotyledonary node A and cotyledonary node B) were tested on MS medium supplemented with different concentrations and combinations of growth regulators (0 to 0.2 mg/L IAA and 1.0 to 5.0 mg/L BA), the results showed that entire cotyledons cultured in MS + BA (2.0mg/L) + IAA(0.2mg/L) achieved the highest regenerated rate (89.67%) and the optimal protocol screened in this experiment had 7.69 ± 0.10 shoots per explants. Adventitious shoots were able to elongate both on MS medium with 0.2 mg/L KT and 0.2 mg/L NAA; IBA 0.3mg/L was found to be effective in the production of root. Acclimatized plantlets transferred to pot resumed growth, and their stems and leaves elongated and expanded in one month. Key words: Watermelon (Citrullus lanatus Thumb.), optimized system, regeneration, cotyledon explants, cotyledonary node.