Hellebrigenin induces apoptosis in colorectal cancer Cells through induction of excessive reactive oxygen species

Traditional Chinese medicine(TCM)has been increasingly applied in both preventing and treating a variety of cancers in the last decades,attributing to its fewer side effects as compared with chemotherapy drugs.Hellebrigenin,a component of Chanpi from the skin of Bufo bufogargarizans Cantor or Duttaphrynus melanostictus has been reported to have an obvious anti-cancer activity on various cancers.However,the effect and mechanism of hellebrigenin on colorectal cancers were still unknown.Herein,the present study demonstrated hellebrigenin significantly reduced viability and triggered apoptosis via the intrinsic pathway in colorectal cancer cell lines HCT116 and HT29 in vitro and in vivo.Moreover,hellebrigenin led to a reduction of mitochondrial membrane potential.In addition,treatment with hellebrigenin could result in the induction of excessive reactive oxygen species,which led to cell apoptosis.These results indicated that hellebrigenin had anti-cancer potential in the treatment of colorectal cancers.

Telomere-to-telomere genome of the allotetraploid legume Sesbania cannabina reveals transposon-driven subgenome divergence and mechanisms of alkaline stress tolerance

Alkaline soils pose an increasing problem for agriculture worldwide,but using stress-tolerant plants as green manure can improve marginal land.Here,we show that the legume Sesbania cannabina is very tolerant to alkaline conditions and,when used as a green manure,substantially improves alkaline soil.To understand genome evolution and the mechanisms of stress tolerance in this allotetraploid legume,we generated the first telomere-to-telomere genome assembly of S.cannabina spanning~2,087 Mb.The assembly included all centromeric regions,which contain centromeric satellite repeats,and complete chromosome ends with telomeric characteristics.Further genome analysis distinguished A and B subgenomes,which diverged approximately 7.9 million years ago.Comparative genomic analysis revealed that the chromosome homoeologs underwent large-scale inversion events(>10 Mb)and a significant,transposon-driven size expansion of the chromosome 5A homoeolog.We further identified four specific alkali-induced phosphate transporter genes in S.cannabina;these may function in alkali tolerance by relieving the deficiency in available phosphorus in alkaline soil.Our work highlights the significance of S.cannabina as a green tool to improve marginal lands and sheds light on subgenome evolution and adaptation to alkaline soils.

Transposable elements play an important role during cotton genome evolution and fiber cell development

Transposable elements(TEs)usually occupy largest fractions of plant genome and are also the most variable part of the structure.Although traditionally it is hallmarked as"junk and selfish DNA",today more and more evidence points out TE’s participation in gene regulations including gene mutation,duplication,movement and novel gene creation via genetic and epigenetic mechanisms.The recently sequenced genomes of diploid cottons Gossypium arboreum(AA)and Gossypium raimondii(DD)together with their allotetraploid progeny Gossypium hirsutum(At At Dt Dt)provides a unique opportunity to compare genome variations in the Gossypium genus and to analyze the functions of TEs during its evolution.TEs accounted for 57%,68.5%and67.2%,respectively in DD,AA and At At Dt Dt genomes.The 1,694 Mb A-genome was found to harbor more LTR(long terminal repeat)-type retrotransposons that made cardinal contributions to the twofold increase in its genome size after evolution from the 775.2 Mb D-genome.Although the 2,173 Mb At At Dt Dt genome showed similar TE content to the A-genome,the total numbers of LTR-gypsy and LTR-copia type TEs varied significantly between these two genomes.Considering their roles on rewiring gene regulatory networks,we believe that TEs may somehow be involved in cotton fiber cell development.Indeed,the insertion or deletion of different TEs in the upstream region of two important transcription factor genes in At or Dt subgenomes resulted in qualitative differences in target gene expression.We suggest that our findings may open a window for improving cotton agronomic traits by editing TE activities.

A Malvaceae-specific miRNA targeting the newly duplicated GaZIP1L to regulate Zn^(2+)ion transporter capacity in cotton ovules

MicroRNAs(miRNAs)play critical roles in regulating gene expression in plants,yet their functions underlying cultivated diploid Gossypium arboreum cotton ovule development are largely unknown.Here,we acquired small RNA profiles from G.arboreum ovules and fibers collected at different growth stages,and identified 46 novel miRNAs that accounted for 23.7%of all miRNAs in G.arboreum reported in the latest plant sRNA database.Through analysis of 84(including 38 conserved)differentially expressed G.arboreum miRNAs,we detected 215 putative protein-coding genes in 26 biological processes as their potential targets.A Malvaceae-specific novel miRNA named gar-miRN44 was found to likely regulate cotton ovule growth by targeting to a newly duplicated Zn^(2+)ion transporter gene GaZIP1L.During cotton ovule development,gar-miRN44 transcript level decreased sharply after 10 to 15 days post-anthesis(DPA),while that of the GaZIP1L increased significantly,with a concomitant increase of Zn^(2+)ion concentration in late ovule developmental stages.Molecular dynamics simulation and ion absorption analysis showed that GaZIP1L has stronger Zn2+ion binding ability than the original GaZIP1,indicating that the newly evolved GaZIP1L may be more suitable for maintaining high Zn2+ion transport capacity that is likely required for cotton ovule growth via enhanced cellulose synthase activities.Our systematic miRNA profiling in G.arboreum and characterization of gar-miRN44 not only contribute to the understanding of miRNA function in cotton,but also provide potential targets for plant breeding.

Sustainable plant disease control: biotic information flow and behavior manipulation

Crop pests and diseases are a major threat to agricultural production worldwide.Farmers utilize massive quantities of chemical pesticides,herbicides,and fungicides for secure crop production.Following the extensive use of pesticides and other chemicals,serious problems regarding human and animal poisoning,agricultural product pollution,and ecological and environmental damage can no longer be ignored(Toju et al.,2018).Therefore,there is an urgent need to develop new strategies and technologies by employing basic research on information flow and cross-talk among crops,insects,and pathogenic microorganisms for sustainable agriculture.In recent years,great progress has been made in understanding the relationship between plants and other organisms to ensure the safety of food production in China and worldwide.

Analysis of the chromatin binding af?nity of retrotransposases reveals novel roles in diploid and tetraploid cotton

LTR-retrotransposable elements are major components of diploid(Gossypium arboreum) and tetraploid(Gossypium hirsutum) cotton genomes that have undergone dramatic increases in copy number during the course of evolution. However, little is known about the biological functions of LTR-retrotransposable elements in cotton. Here, we show that a copia-like LTRretrotransposable element has maintained considerable activity in both G. arboreum and G. hirsutum. We identified two functional domains of the retrotransposon and analyzed their expression levels in various cotton tissues, including leaves, ovules, and germinating seeds.ChIP-qPCR(chromatin immunoprecipitation followed by quantitative PCR), using a copia-specific antibody,established that copia-like proteins primarily bind to the first exons of several protein-coding genes in cotton cells. This finding suggests that retrotransposons play a novel, important role in regulating the transcriptional activities of protein-coding genes with various biological activities.

Genome-scale analysis of the cotton KCS gene family revealed a binary mode of action for gibberellin A regulated fiber growth

Production of b-ketoacyl-Co A, which is catalyzed by 3-ketoacyl-CoA synthase（KCS）, is the first step in very long chain fatty acid（VLCFA） biosynthesis. Here we identified 58 KCS genes from Gossypium hirsutum, 31 from G. arboreum and 33 from G. raimondii by searching the assembled cotton genomes. The gene family was divided into the plant-specific FAE1-type and the more general ELO-type. KCS transcripts were widely expressed and 32 of them showed distinct subgenome-specific expressions in one or more cotton tissues/organs studied. Six Gh KCS genes rescued the lethality of elo2Δelo3Δ yeast double mutant,indicating that this gene family possesses diversified functions.Most KCS genes with GA-responsive elements（GAREs） in the promoters were significantly upregulated by gibberellin A_3（GA）.Exogenous GA_3 not only promoted fiber length, but also increased the thickness of cell walls significantly. GAREs present also in the promoters of several cellulose synthase（CesA） genes required for cell wall biosynthesis and they were all induced significantly by GA_3. Because GA treatment resulted in longer cotton fibers with thicker cell walls and higher dry weight per unit cell length, we suggest that it may regulate fiber elongation upstream of the VLCFA-ethylene pathway and also in the downstream steps towards cell wall synthesis.

Plant polyploidy and evolution

Polyploidy refers to two or more complete sets of chromosomes that are combined within a nucleus,and includes both autopolyploidy and allopolyploidy(Otto 2007).Polyploidy is a recurring theme in the evolutionary history of plants and it has been considered an important mechanism for speciation and also for adaptability to changing environments(Shimizu-Inatsugi et al.2017).In nature,about one-third of flowering plants are polyploids,and a great majority of them are allopolyploids.There are many cultivated allopolyploid species,such as cotton,Brassica and potato,the possible evolutionary history of which can be inferred with high certainty.

PROTEIN S-ACYL TRANSFERASE 13/16 modulate disease resistance by S-acylation of the nucleotide binding,leucine-rich repeat protein R5L1 in Arabidopsis

Nucleotide binding,leucine-rich repeat(NB-LRR)proteins are critical for disease resistance in plants,while we do not know whether S-acylation of these proteins plays a role during bacterial infection.We identified 30 Arabidopsis mutants with mutations in NB-LRR encoding genes from the Nottingham Arabidopsis Stock Center and characterized their contribution to the plant immune response after inoculation with Pseudomonas syringae pv tomato DC3000(Pst DC3000).Of the five mutants that were hyper-susceptible to the pathogen,three(R5L1,R5L2 and RPS5)proteins contain the conserved S-acylation site in the N-terminal coiled-coil(CC)domain.In wild-type(WT)Arabidopsis plants,R5L1 was transcriptionally activated upon pathogen infection,and R5L1 overexpression lines had enhanced resistance.Independent experiments indicated that R5L1 localized at the plasma membrane(PM)via S-acylation of its N-terminal CC domain,which was mediated by PROTEIN S-ACYL TRANSFERASE 13/16(PAT13,PAT16).Modification of the S-acylation site reduced its affinity for binding the PM,with a consequent significant reduction in bacterial resistance.PM localization of R5L1 was significantly reduced in pat13 and pat16 mutants,similar to what was found for WT plants treated with 2-bromopalmitate,an S-acylationblocking agent.Transgenic plants expressing R5L1 in the pat13 pat16 double mutant showed no enhanced disease resistance.Overexpression of R5L1 in WT Arabidopsis resulted in substantial accumulation of reactive oxygen species after inoculation with Pst DC3000;this effect was not observed with a mutant R5L1 carrying a mutated Sacylation site.Our data suggest that PAT13-and PAT16-mediated S-acylation of R5L1 is crucial for its membrane localization to activate the plant defense response.

Insights of section-wide pan-genome into hybrid potato breeding

Crop improvement for high yield,good nutrition,and strong resistance is key to feed the growing population of the world.Breeding efforts with the aid of genomics information have dramatically shortened the time for new crop varieties development(Huang et al.,2021;Huang and Zhu,2021;Yu et al.,2021).To date,pan-genomics studies have been reported for many important crops(Gao et al.,2019;Chen et al.,2022.)

Breeding cotton with superior fiber quality:identification and utilization of multiple elite loci and exotic genetic resources

In the last decade,cotton genomics had great progress in genome assembling(Li et al.,2015;Huang et al.,2020)and agriculturally important locus identification(Du et al.,2018;Ma et al.,2018;Li et al.,2021).Upland cotton(Gossypium hirsutum)is one of the most important cash crops cultivated worldwide.The fiber quality of cotton directly determines its economic value,and therefore enhancing fiber quality is always the primary task in cotton breeding practices(Xia et al.,2019;Huang et al.,2021).

Cotton functional genomics reveals global insight into genome evolution and fiber development

Due to the economic value of natural textile fiber, cotton has attracted much research attention, which has led to the publication of two diploid genomes and two tetraploid genomes. These big data facilitate functional genomic study in cotton, and allow researchers to investigate cotton genome structure, gene expression, and protein function on the global scale using high-throughput methods. In this review, we summarized recent studies of cotton genomes. Population genomic analyses revealed the domestication history of cultivated upland cotton and the roles of transposable elements in cotton genome evolution.Alternative splicing of cotton transcriptomes was evaluated genome-widely. Several important gene families like MYC, NAC, Sus and GhPLDal were systematically identified and classified based on genetic structure and biological function. High-throughput proteomics also unraveled the key functional proteins correlated with fiber development. Functional genomic studies have provided unprecedented insights into global-scale methods for cotton research.