A transcriptome analysis uncovers Panax notoginseng resistance to Fusarium solani induced by methyl jasmonate

Diqiu Liu,Qin Zhao,Xiuming Cui,Rui Chen,Xin Li,Bingling Qiu,Feng Ge 한국유전학회 2019 Genes & Genomics Vol.41 No.12

Background Panax notoginseng is a famous Chinese herbal medicine, but the root rot disease mainly caused by Fusarium solani severely reduces the yield and quality of its medicinal materials. Objective The defense priming in P. notoginseng through exogenous application of signaling molecule will supply theoretical support for the exogenous regulation of disease resistance in P. notoginseng. Methods In this study, the exogenous application of methyl jasmonate (MeJA) increased P. notoginseng’s resistance to F. solani. Furthermore, the P. notoginseng transcriptome during F. solani infection was investigated through next-generation sequencing to uncover the resistance mechanism of P. notogingseng induced by MeJA. Results The de novo assembly of transcriptome sequences produced 80,551 unigenes, and 36,771 of these unigenes were annotated by at least one database. A differentially expressed gene analysis revealed that a large number of genes related to terpenoid backbone biosynthesis, phenylalanine metabolism, and plant–pathogen interactions were predominantly upregulated by MeJA. Moreover, jasmonic acid (JA) biosynthesis-related genes and the JA signaling pathway genes, such as linoleate 13S-lipoxygenase, allene oxide cyclase, allene oxide synthase, TIFY, defensin, and pathogenesis-related proteins, showed increased transcriptional levels after inoculation with F. solani. Notably, according to the gene expression analysis, JA and ethylene signaling pathways may act synergistically to positively regulate the defense responses of P. notoginseng to F. solani. Conclusion JA signaling appears to play a vital role in P. notoginseng responses to F. solani infection, which will be helpful in improving the disease resistance of P. notoginseng cultivars as well as in developing an environmentally friendly biological control method for root rot disease.

WRKY22 Transcription Factor Mediates Dark-Induced Leaf Senescence in Arabidopsis

Xiang Zhou,Diqiu Yu,Yanjuan Jiang 한국분자세포생물학회 2011 Molecules and cells Vol.31 No.4

Arabidopsis WRKY proteins are plant-specific transcrip-tion factors, encoded by a large gene family, which contain the highly conserved amino acid sequence WRKYGQK and the zinc-finger-like motifs, Cys_2His_2 or Cys_2HisCys. They can recognize and bind the TTGAC(C/T) W-box cis-elements found in the promoters of target genes, and are involved in the regulation of gene expression during pathogen defense, wounding, trichome development, and senescence. Here we investigated the physiological function of the Arabidopsis WRKY22 transcription factor during dark-induced senescence. WRKY22 transcription was suppressed by light and promoted by darkness. In addi-tion, AtWRKY22 expression was markedly induced by H_2O_2. These results indicated that AtWRKY22 was involved in signal pathways in response to abiotic stress. Dark-treated AtWRKY22 over-expression and knockout lines showed accelerated and delayed senescence phenotypes, respectively, and senescence-associated genes exhibited increased and decreased expression levels. Mutual regulation existed between AtWRKY22 and AtWRKY6, AtWR-KY53, and AtWRKY70, respectively. Moreover, AtWRKY22 could influence their relative expression levels by feedback regulation or by other, as yet unknown mechanisms in response to dark. These results prove that AtWRKY22 participates in the dark-induced senescence signal transduction pathway.

A bZIP transcription factor, LrbZIP1, is involved in Lilium regale Wilson defense responses against Fusarium oxysporum f. sp. lilii

Nannan Zhang,Diqiu Liu,Wei Zheng,Hua He,Bo Ji,Qing Han,Feng Ge,Chaoyin Chen 한국유전학회 2014 Genes & Genomics Vol.36 No.6

The basic leucine zipper (bZIP) proteins areubiquitous in plants and play important roles in plantdefense responses. In this study, based on an expressedsequence tag from a suppression subtractive hybridizationcDNA library of Lilium regale Wilson during Fusariumoxysporum f. sp. lilii infection, a novel bZIP transcriptionfactor gene LrbZIP1 was isolated from L. regale root usingthe rapid amplification of cDNA ends method. The predictedprotein of LrbZIP1 with 142 amino acid residuescontains a basic domain signature and a leucine zippermotif. The quantitative reverse transcription-PCR (qRTPCR)analysis showed that the transcription level of Lrb-ZIP1 was higher in roots of L. regale than in young stemsand leaves. Moreover, the expression of LrbZIP1 was upregulatedin the incompatible interaction between L. regaleand F. oxysporum f. sp. lilii as well as after treatments withstress-related signaling molecules. To verify the function ofLrbZIP1, a constitutive expression vector of LrbZIP1 wasconstructed and transferred into tobacco (Nicotiana tabacumL. cv Xanthi). The results of Southern blotting andqRT-PCR analyses demonstrated that the LrbZIP1 wasintegrated into genome of the tobacco transformants andhighly expressed. Under normal conditions, the T1 transgenictobacco lines showed higher antioxidant enzymeactivities and transcription levels of several resistancerelatedgenes than the wild type. Moreover, the T1 transgenictobacco plants showed strong resistance to F. oxysporumf. sp. lilii infection.

The PR10 gene family is highly expressed in Lilium regale Wilson during Fusarium oxysporum f. sp. lilii infection

Hua He,Diqiu Liu,Nannan Zhang,Wei Zheng,Qing Han,Bo Ji,Feng Ge,Chaoyin Chen 한국유전학회 2014 Genes & Genomics Vol.36 No.4

Pathogenesis-related (PR) proteins play keyroles in plant responses to pathogens and abiotic stresses. In this study, nine novel PR genes were isolated from Liliumregale Wilson, which is a wild lily species of Chinawith high-level resistance to the soilborne fungal pathogenFusarium oxysporum f. sp. lilii, and homology analysisclassified them into the PR10 family. These novel LrPR10swere clustered together with PR10s from monocotyledonsin a phylogenetic tree, moreover, phylogenetic analysisdivided the nine LrPR10s into two groups. The main-chainconformation and folding patterns of the LrPR10s werehighly conserved with other plant PR10s. The expressionpatterns of the nine LrPR10s in L. regale during normaldevelopment were examined by QRT-PCR, and the transcriptionlevels of the LrPR10s were relatively high inroots. Furthermore, QRT-PCR analysis indicated that theexpression levels of LrPR10-1, LrPR10-2, LrPR10-5,LrPR10-6, and LrPR10-7 in L. regale roots were up-regulatedby two or more stress-related signaling moleculesincluding salicylic acid, jasmonic acid, ethylene, and H2O2,while the other four LrPR10s were repressed by these foursignaling molecules. In addition, five members of theLrPR10 gene family including LrPR10-2, LrPR10-4,LrPR10-5, LrPR10-6, LrPR10-7, and LrPR10-9 werestrongly induced by F. oxysporum in resistant L. regalecompared with the susceptible Lilium Oriental hybrid‘Siberia’. The other four LrPR10s were down-regulated byF. oxysporum infection. In summary, our results indicatethat the members of PR10 gene family are involved inL. regale defense responses against F. oxysporum f. sp. lilii.

Identification of an Arabidopsis Nodulin-Related Protein in Heat Stress

Qiantang Fu,Shujia Li,Diqiu Yu 한국분자세포생물학회 2010 Molecules and cells Vol.29 No.1

We identified a Nodulin-related protein 1 (NRP1) encoded by At2g03440, which was previously reported to be RPS2 interacting protein in yeast-two-hybrid assay. Northern blotting showed that AtNRP1 expression was suppressed by heat stress (42°C) and induced by low temperature (4°C) treatment. Strong GUS staining was observed in the sites of meristematic tissues of pAtNRP1:: GUS transgenic plants, such as shoot apex and root tips, young leaf veins, stamens and stigmas of flowers, and abscission layers of young siliques. To study AtNRP1 biological functions, we have characterized both loss-of-function T-DNA insertion and transgenic overexpression plants for AtNRP1 in Arabidopsis. The T-DNA insertion mutants displayed no obvious difference as compared to wild-type Arabidopsis under heat stress, but the significant enhanced suscepti-bility to heat stress was revealed in two independent AtNRP1-overexpressing transgenic lines. Further study found that the decreased thermtolerance in AtNRP1-overexpressing lines accompanied significantly decreased accumulation of ABA after heat treatment, which was probably due to AtNRP1 playing a role in negative-feedback regulation of the ABA synthesis pathway. These results support the viewpoint that the application of ABA inhibits nodulation and nodulin-related gene expression and threaten adverse ambient temperature can impact the nodulin-related gene expression.

Analysis of the Cold-Responsive Transcriptome in the Mature Pollen of Arabidopsis

Zou Changsong,Yu Diqiu 한국식물학회 2010 Journal of Plant Biology Vol.53 No.6

Mature pollen is very sensitive to cold stress in chilling-sensitive plants. To understand the genetic regulation of tolerance to cold stress, we analyzed the transcript expression profile in mature pollen of Arabidopsis using Affymetrix GeneChips containing ∼24,000 genes. Expression of 2,127 genes was cold-regulated, of which 697 genes were upregulated and 1,430 genes were downregulated. Further analysis showed that a large number of signal transduction components were significantly affected by cold treatment, indicating extensive changes in the gene regulatory networks of mature pollen. Many coldresponsive genes encode transcription factors, suggesting a multitude of transcriptional cascades. A number of genes important for the biosynthesis or signaling of plant hormones, such as abscisic acid, auxin, and jasmonate,were regulated by cold stress, which is of potential importance in coordinating cold tolerance with pollen growth and development. In addition, 159 mature pollenspecific genes that might be involved in pollen viability were also cold-regulated. Expression of the cold-responsive transcripts identified by microarray analysis was confirmed by quantitative real-time PCR. Our study provides an overall picture of the cold-responsive transcriptome in Arabidopsis pollen and is valuable for understanding gene regulation in response to cold stress and the molecular mechanisms of cold tolerance in mature pollen.

Bacillus megaterium Strain XTBG34 Promotes Plant Growth by Producing 2-Pentylfuran

Changsong Zou,Zhifang Li,Diqiu Yu 한국미생물학회 2010 The journal of microbiology Vol.48 No.4

Several chemical changes in soil are associated with plant growth-promoting rhizobacteria. An endosporeforming bacterium, strain XTBG34, was isolated from a Xishuangbanna Tropical Botanical Garden soil sample and identified as Bacillus megaterium. The strain’s volatiles had remarkable plant growth promotion activity in Arabidopsis thaliana plants; after 15 days treatment, the fresh weight of plants inoculated with XTBG34 was almost 2-fold compared with those inoculated with DH5α. Head space volatile compounds produced by XTBG34, trapped with headspace solid phase microextraction and identified by gas chromatography–mass spectrometry, included aldehydes, alkanes, ketones and aroma components. Of the 11 compounds assayed for plant growth promotion activity in divided Petri plates, only 2-pentylfuran increased plant growth. We have therefore identified a new plant growth promotion volatile of B. megaterium XTBG34, which deserves further study in the mechanisms of interaction between plant growth-promoting rhizobacteria and plants.

Transcriptome analysis reveals putative pathogenesis genes in Alternaria panax during infecting Panax notoginseng leaves

Shah Taif,Liu Diqiu,Cui XiuMing 한국유전학회 2022 Genes & Genomics Vol.44 No.7

Background: Alternaria panax is the causative agent of black spot disease in Panax notoginseng, which causes significant yield loss. However, the molecular mechanisms underlying its pathogenicity remain mostly unknown. Objective: We sequenced the transcriptome of A. panax during infecting P. notoginseng leaves using next-generation RNA-seq to understand the molecular aspects of black spot disease. Methods: In this study, we sequenced the A. panax transcriptome during infecting P. notoginseng leaves through next-generation sequencing to explore the pathogenesis genes that may be responsible for black spot disease on P. notoginseng. Result: The de novo transcriptome assembly of A. panax produced 23,036 unigenes, of which 18,096 genes were functionally annotated by at least one protein database. GO enrichment analysis and KEGG pathways of differentially up-regulated genes suggest that most genes are associated with metabolic processes, catalytic activity, starch, and sucrose metabolism during infection. Many pathogenesis-associated genes, including genes encoding secreted proteins, candidate secreted effectors, cell wall degrading enzymes, transcription factors, and transporters, were up-regulated in A. panax during infection. In addition, the secondary metabolite biosynthesis genes, including cytochrome P450, and nonribosomal peptide synthetases, were also identified in this study. Conclusions: Differential gene expression analysis has confirmed that A. panax infection was mainly present in the middle and final stages. The findings show that these pathogenesis-associated genes in A. panax may be critical for the P. notoginseng black spots disease.

Identification of an Arabidopsis Nodulin-Related Protein in Heat Stress

Fu, Qiantang,Li, Shujia,Yu, Diqiu Korean Society for Molecular and Cellular Biology 2010 Molecules and cells Vol.29 No.1

We identified a Nodulin-related protein 1 (NRP1) encoded by At2g03440, which was previously reported to be RPS2 interacting protein in yeast-two-hybrid assay. Northern blotting showed that AtNRP1 expression was suppressed by heat stress (42$^{\circ}C$) and induced by low temperature (4$^{\circ}C$) treatment. Strong GUS staining was observed in the sites of meristematic tissues of pAtNRP1:: GUS transgenic plants, such as shoot apex and root tips, young leaf veins, stamens and stigmas of flowers, and abscission layers of young siliques. To study AtNRP1 biological functions, we have characterized both loss-of-function T-DNA insertion and transgenic overexpression plants for AtNRP1 in Arabidopsis. The T-DNA insertion mutants displayed no obvious difference as compared to wild-type Arabidopsis under heat stress, but the significant enhanced susceptibility to heat stress was revealed in two independent AtNRP1-overexpressing transgenic lines. Further study found that the decreased thermtolerance in AtNRP1-overexpressing lines accompanied significantly decreased accumulation of ABA after heat treatment, which was probably due to AtNRP1 playing a role in negative-feedback regulation of the ABA synthesis pathway. These results support the viewpoint that the application of ABA inhibits nodulation and nodulin-related gene expression and threaten adverse ambient temperature can impact the nodulin-related gene expression.

Arabidopsis MiR396 Mediates the Development of Leaves and Flowers in Transgenic Tobacco

Fengxi Yang,Gang Liang,Dongmei Liu,Diqiu Yu 한국식물학회 2009 Journal of Plant Biology Vol.52 No.5

MicroRNAs (miRNAs) are single-stranded, noncoding small RNAs that usually function as posttranscriptional negative regulators by base pairing to target genes. They are pivotal to plant development. MiR396 is conserved among plant species and is predicted to target GRF (growth-regulating factor) genes in Arabidopsis. Here, overexpression of ath-miR396 in tobacco reduced the levels of three NtGRF-like genes containing an miR396 match site. Furthermore, its elevated expression resulted in a small, narrow leaf phenotype similar to that found with the Arabidopsis grf1grf2grf3 triple mutant. We also demonstrated that 35S:MIR396a transgenic plants were defective in the four whorls of floral organs. These results provide a link between the miR396- mediated regulatory pathway of NtGRF-like gene expression and the developmental processes for leaves and flowers in tobacco.