Dynamics of 18 (<i>Sophora japonica</i>) Tree Community’s Crown Volume along Elevation Gradient in <i>Ye County</i>

Applying plant community diversity techniques and SPSS statistic analysis, we quantified the relationship between crown volume of 18 (Sophora japonica) tree communities and elevation along different elevation gradient in Ye County in the study. We concluded that there was a significantly positive correlation between crown volume of 18 (Sophora japonica) tree communities and elevation gradient (P Sophora japonica) tree communities increased along elevation from 50 m to 200 m in Ye County in 2018. Therefore, understanding dynamic connecting crown volume of 18 (Sophora japonica) communities and elevation can be not just applied to preserve of (Sophora japonica) tree communities, but also applied to sustainable of biodiversity and processes of tree community’s crown volume along elevation.

Genetic map construction and functional characterization of genes within the segregation distortion regions(SDRs)in the F_(2:3) populations derived from wild cotton species of the D genome

Background:Segregation distortion(SD)is a common phenomenon among stable or segregating populations,and the principle behind it still puzzles many researchers.The F2:3 progenies developed from the wild cotton species of the D genomes were used to investigate the possible plant transcription factors within the segregation distortion regions(SDRs).A consensus map was developed between two maps from the four D genomes,map A derived from F2:3 progenies of Gossypium klotzschianum and G.davidsonii while Map B from G.thurberi and G.trilobum F2:3 generations.In each map,188 individual plants were used.Results:The consensus linkage map had 1492 markers across the 13 linkage groups with a map size of 1467.445 cM and an average marker distance of 1.0370 cM.Chromosome D502 had the highest percentage of SD with 58.6%,followed by Chromosome D507 with 47.9%.Six thousand and thirty-eight genes were mined within the SDRs on chromosome D502 and D507 of the consensus map.Within chromosome D502 and D507,2308 and 3730 genes were mined,respectively,and were found to belong to 1117 gourp out of which 622 groups were common across the two chromosomes.Moreover,genes within the top 9 groups related to plant resistance genes(R genes),whereas 188 genes encoding protein kinase domain(PF00069)comprised the largest group.Further analysis of the dominant gene group revealed that 287 miRNAs were found to target various genes,such as the gra-miR398,gramiR5207,miR164a,miR164b,miR164c among others,which have been found to target top-ranked stress-responsive transcription factors such as NAC genes.Moreover,some of the stress-responsive cis-regulatory elements were also detected.Furthermore,RNA profiling of the genes from the dominant family showed that higher numbers of genes were highly upregulated under salt and osmotic stress conditions,and also they were highly expressed at different stages of fiber development.Conclusion:The results indicated the critical role of the SDRs in the evolution of the key regulatory genes in plants.

Comparative transcriptome and lipidome reveal that a low K^(+) signal effectively alleviates the effect induced by Ca^(2+) deficiency in cotton fibers

Calcium(Ca^(2+))plays an important role in determining plant growth and development because it maintains cell wall and membrane integrity.Therefore,understanding the role of Ca^(2+)in carbon and lipid metabolism could provide insights into the dynamic changes in cell membranes and cell walls during the rapid elongation of cotton fibers.In the present study,we found that the lack of Ca^(2+)promoted fiber elongation and rapid ovule expansion,but it also caused tissue browning in the ovule culture system.RNA-sequencing revealed that Ca^(2+)deficiency induced cells to be highly oxidized,and the expression of genes related to carbon metabolism and lipid metabolism was activated significantly.All gene members of nine key enzymes involved in glycolysis were up-regulated,and glucose was significantly reduced in Ca^(2+)deficiency-treated tissues.Ca^(2+)deficiency adjusted the flowing of glycolysis metabolic.However,low K^(+)recovered the expression levels of glycolysis genes and glucose content caused by Ca^(2+)deficiency.Electrospray ionizationtandem mass spectrometry technology was applied to uncover the dynamic profile of lipidome under Ca^(2+)and K^(+)interacted conditions.Ca^(2+)deficiency led to the decrease of fatty acid(FA),diacylglycerol(DAG),glycolipid and the significant increase of triacylglycerol(TAG),phospholipid phosphatidylethanolamine(PE),phosphatidylglycerol(PG),and PC(phosphatidylcholine).Low K^(+)restored the contents of FA,phospholipids,and glycolipids,effectively relieved the symptoms caused by Ca^(2+)deficiency,and recovered the development of fiber cells.This study revealed dynamic changes in transcript and metabolic levels and uncovered the signaling interaction of Ca^(2+)deficiency and low K^(+)in glycolysis and lipid metabolism during fiber development.

Cotton GhBRC1 regulates branching,flowering,and growth by integrating multiple hormone pathways

Cotton architecture is partly determined by shoot branching and flowering patterns.Gh BRC1 was previously identified by RNA-seq analysis of nulliplex-branching and normal-branching cotton.However,the roles of Gh BRC1 in cotton remain unclear.In the present study,investigations of nuclear localization and transcriptional activity indicated that Gh BRC1 has characteristics typical of transcription factors.Gene expression analysis showed that Gh BRC1 was highly expressed in axillary buds but displayed different expression patterns between the two branching types.Overexpression of Gh BRC1 in Arabidopsis significantly inhibited the number of branches and promoted flowering.In contrast,silencing Gh BRC1 in cotton significantly promoted seedling growth.Gh BRC1 was induced by multiple hormones,including strigolactones,which promoted seedling growth and seed germination of Arabidopsis plants overexpressing Gh BRC1.Consistent with these findings,RNA-seq analysis of virus-induced gene silencing treated cotton revealed that a large number of genes were differentially expressed between Gh BRC1-silenced and control plants,and these genes were significantly enriched in plant hormone signalling pathways.Together,our data indicates that Gh BRC1 regulates plant branching and flowering through multiple regulatory pathways,especially those regulating plant hormones,with functions partly differing from those of Arabidopsis BRC1.These results provide insights into the molecular mechanisms controlling plant architecture,which is important for breeding cotton with ideal plant architecture and high yield.

Screening of abiotic stress-responsive cotton genes using a cotton full-length cDNA overexpressing Arabidopsis library

Cotton(Gossypium hirsutum L.)is a major crop and the main source of natural fiber worldwide.Because various abiotic and biotic stresses strongly influence cotton fiber yield and quality,improved stress resistance of this crop plant is urgently needed.In this study,we used Gateway technology to construct a normalized full-length cDNA overexpressing(FOX)library from upland cotton cultivar ZM12 under various stress conditions.The library was transformed into Arabidopsis to produce a cotton-FOX-Arabidopsis library.Screening of this library yielded 6,830 transgenic Arabidopsis lines,of which 757 were selected for sequencing to ultimately obtain 659 cotton ESTs.GO and KEGG analyses mapped most of the cotton ESTs to plant biological process,cellular compo-nent,and molecular function categories.Next,156potential stress-responsive cotton genes were identified from the cotton-FOX-Arabidopsis library under drought,salt,ABA,and other stress conditions.Four stress-related genes identified from the library,designated as GhCAS,GhAPX,GhSDH,and GhPOD,were cloned from cotton complementary DNA,and their expression patterns under stress were analyzed.Phenotypic experiments in-dicated that overexpression of these cotton genes in Arabidopsis affected the response to abiotic stress.The method developed in this study lays a foundation for high-throughput cloning and rapid identification of cotton functional genes.

Suppression of the homeobox gene HDTF_1 enhances resistance to Verticillium dahliae and Botrytis cinerea in cotton

Development of pathogen-resistant crops, such as fungus-resistant cotton, has significantly reduced chemical application and improved crop yield and quality. However, the mechanism of resistance to cotton pathogens such as Verticillium dahliae is still poorly understood. In this study, we characterized a cotton gene （HDTF1） that was isolated following transcriptome profiling during the resistance response of cotton to V. dahliae. HDTFI putatively encodes a homeodomain transcription factor, and its expression was found to be down-regulated in cotton upon inoculation with V. dahliae and Botrytis cinerea. To characterise the involvement of HDTF1 in the response to these pathogens, we used virusinduced gene silencing （VlGS） to generate HDTFl-silenced cotton. VIGS reduction in HDTF1 expression significantly enhanced cotton plant resistance to both pathogens. HDTF1 silencing resulted in activation of jasmonic acid （JA）-mediated signaling and JA accumulation. However, the silenced plants were not altered in the accumulation of salicylic acid （SA） or the expression of marker genes associated with SA signaling. These results suggest that HDTF1 is a negative regulator of the JA pathway, and resistance to V. dahliae and B. cinerea can be engineered by activation of JA signaling.

Hydrogen peroxide modulates abscisic acid signaling in root growth and development in Arabidopsis

Exogenous abscisic acid(ABA)can inhibit root growth and promote formation of more root hairs in the root tip of Arabidopsis.However,the molecular mechanisms that underlie root ABA signaling are largely unknown.We report here that hydrogen peroxide(H2O2)reduces the root growth of wild type, and the phenotype of H2O2 on the root growth is similar to ABA response.Meanwhile ABA-induced changes in the morphology of root system can be partly reversed by ascorbic acid in wild type and abolished in NADPH oxidase defective mutant atrbohF and atrbohC.Further,ABA can induce H2O2 accumulation in the root cells and enhance transcription level of OXI1,which is necessary for many more AOS-dependent processes such as root hair growth in Arabidopsis.Our results suggest that H2O2 as an important signal molecule is required for the ABA-regulated root growth and development in Arabidopsis.

Nia1 and Nia2 are Involved in Exogenous Salicylic Acid-induced Nitric Oxide Generation and Stomatal Closure in Arabidopsis

Phytohormone salicylic acid （SA） plays important roles in plant responses to environmental stress. However, knowledge about the molecular mechanisms for SA affecting the stomatal movements is limited. In this paper, we demonstrated that exogenous SA significantly induced stomatal closure and nitric oxide （NO） generation in Arabidopsis guard cells based on genetic and physiological data. These effects were significantly inhibited by the NO scavenger c-PTIO, NO synthase （NOS） inhibitor L-NAME or nitrate reductase suppressor tungstate respectively, implying that NOS and nitrate reductase （NR） participate in SA-evoked stomatal closing. Furthermore, the effects of SA promotion of stomatal closure and NO synthesis are significantly suppressed in NR single mutants of nial, nia2 or double mutant niallnia2, compared with the wild type plants. This suggests that both Nial and Nia2 are involved in SA-stimulated stomatal closure. In addition, pharmacological experiments showed that protein kinases, cGMP and cADPR are involved in SA-mediated NO accumulation and stomatal closure induced by SA in Arabidopsis.