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ABSTRACT: Cyclic adenosine mono phosphate (cAMP)-dependent protein kinase A (PKA) is an important mediator of signal transduction in eukaryotic cells. Thus, identifying its function is necessary to understand the cAMP signaling network. StPKA-c, the PKA catalytic subunit gene in Setosphaeria turcica, was investigated by RNA interference technology. Transformant strains M3, M5, and M9 with diverse StPKA-c silencing efficiency were confirmed by reverse transcription-polymerase chain reaction and northern blot. Compared with the wild-type strain 01-23, the transformant strains exhibited increased growth rate and significantly decreased conidium production. In addition, the ratios of spore germination and appressorium formation and penetration were slightly reduced. Relative to the wild-type strain, the transformants demonstrated different colony color, greatly reduced pathogenicity, and similar HT-toxin activity. Further studies showed that the content of intracellular melanin in the transformants significantly decreased and the transcription of transcriptional factor StMR was down-regulated correspondingly. The transcription and enzyme activity of xylanase was also impaired. Thus, we proposed that StPKA-c was mainly involved in the mycelium growth, conidiation, and pathogenesis of S. turcica. Furthermore, it was positively correlated with the biosyntheses of melanin and xylanase but dispensable for the activity of HT-toxin. © 2013 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.
FEMS Microbiology Letters 04/2013; · 2.04 Impact Factor
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ABSTRACT: The proteins of Ras family are a large group of monomeric GTPases and act as molecular switches transducing extracellular signals into the cell in higher eukaryotes. However, little is known about roles of Ras family in the foliar pathogens. In this research, we cloned the gene named StRas2 encoding Ras in Setosphaeria turcica and investigated its function by RNA interference technology. We found that the growth rate of RNAi transformants named as R1, R2, R3, R4, R5 and R6, in which the StRas2 silencing efficiency fell in turn. With the highest silencing efficiency, the transformant R1 showed anomalistic hyphae morphology, indicating its growth was significantly affected. The transformants with a middle-silencing efficiency, such as R3, R4, displayed a delay when forming appressoria and invasive hyphae. R1 could not form conidia and appressoria. However, the conidial formation in R5 and R6 was significantly reduced, and these two transformants could form appressoria and penetrate the artificial cellophane, only that its invasive hyphae were fascicular and rarely branched. The HT-toxin biological activity of all transformants showed no difference. All results suggested that StRas2 is involved in the morphogenesis, conidiation, and appressorium development and is not related to the biosynthesis of HT-toxin.
Microbiological Research 03/2012; 167(8):478-86. · 2.31 Impact Factor
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ABSTRACT: A Setosphaeria turcica gene encoding the catalytic subunit of calcineurin was cloned using degenerated primers corresponding to conserved domains of Ser/Thr protein phosphatases and its complete cDNA (GenBank accession No. EF 407562) was obtained with RACE method. It's validated single copied model by southern hybridization. Furthermore, the CNA inhibitor Cyclosporin A (CsA) exhibited potent antifungal activity against conidial germination and appressorium formation of S. turcica. The inhibition ratio was positively correlated to CsA concentration. However, appressorium formation was more sensitive than conidium germination to the inhibitor at the same concentration. It was suggested that CNA might play an important role in the pathogenicity of S. turcica.
Hereditas (Beijing) 10/2009; 31(10):1059-64.
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ABSTRACT: Genemonic DNA and cDNA homologous fragments of the scd (scytalone dehydratase) gene were obtained by polymerase chain reaction (PCR) amplification from degenerated primer sets designed on the basis of the conserved amino acid regions of scytalone dehydratase and polyketide synthase domains from others fungis. The completed cDNA sequence of scd in E. turcica was obtained by the method of SMART-RACE and 3' RACE. There is one open reading frame composed of 181 codons and two deduced introns of 50 and 78 nucleotides in the scd gene. The deduced amino acid sequence of the scd showed high similarity to the amino acid sequence of scytalone dehydratase from Bipolaris oryzae. Carpropamid, a specific inhibitor, could inhibit the conidial germination and appressorium production of E. turcica within 24h treatment but no evident inhibitory effect after 24h . The experimental results also suggested that E. turcica could not penetrate the surface of corn tissue or increase in the corn tissue. It was conclusion that scd gene might play an important role in melanin biosynthetic pathway and pathogenicity of E. turcica.
ACTA MICROBIOLOGICA SINICA 01/2008; 47(6):1013-8.
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ABSTRACT: A repeated sequence with a length of 560 bp, termed as DH17, was obtained during PCR amplification of rice NBS-LRR homologues. A repeated unit of 352 bp in the DH17 fragment was revealed through sequence analysis and comparison, which has a high homology with the known sequences of OS48 and TrsA, and belongs to the same repeat family. Southern hybridization displayed that there are higher DH17 copies in the genome of an indica variety, ZYQ8,than that in the genome of japonica variety, JX17. The tandom repeated DH17 sequence was mapped on the long arm end of chromosome 12 through RFLP analysis of a double haploid population derived from ZYQ8 and JX17 using DH17 as a probe.
Hereditas (Beijing) 12/2003; 25(6):691-4.
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ABSTRACT: Systemic studies on the effects of mitogen-activated protein kinase (MAPK) signal transduction pathway on the growth and development of Setosphaeria turcica is helpful not only in understanding the molecular mechanism of pathogenhost interaction but also in the effective control of the diseases caused by S. turcica. U0126, the specific MEK inhibitor, is used to treat S. turcica before the observation of the conidial germination, appressorium production, and pathogenicity of the pathogen. There is no significant effect of U0126 on the colony morphology and mycelium growth of the pathogen. After treatment with U0126, the growth of mycelium and conidia are normal, but the conidial germination, appressorium production, and pathogenicity of S. turcica on susceptible corn leaves are significantly inhibited. Under the definite concentration scope, an increase in U0126 concentration increases the inhibition degree of conidial germination and appressorium production, but the inhibition degree decreases with elongation of treatment time. The conidial germination, appressorium production, and pathogenicity of S. turcica on susceptible corn leaves are regulated by the MAPK pathway inhibited by U0126.
Agricultural Sciences in China.
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ABSTRACT: Bipolaris oryzae is a severe rice disease, resulting in significant economic losses. MYB73 gene of Arabidopsis was isolated based on T-DNA insertion mutants whose lose-of-function mutant increased susceptibility to B. oryzae. Results of staining for H2O2 revealed that infection of incompatible B. oryzae caused much more strong brown patches on the leaves of myb73 mutant than those on the leaves of wild type. Expression of MYB73 gene was induced by B. oryzae. Its increased expression was severely impaired in the myb73 mutant. Expression of MYB73 was severely decreased in the npr1, jar1, eds5, and sid2 mutants, suggesting MYB73 gene participates in the jasmonate (JA) and salicylic acid (SA) signaling pathways. Expression of MYB73 who encoded an R2R3 MYB transcription factor was increased by SA, JA, and ethylene (ET) treatments. The cDNA full-length sequence of MYB73 was 960 bp and a protein with 320 amino acids was encoded. The predicted molecular weight of MYB73 was 34.85 kDa. The expression of MYB73 gene was induced within 24 h of the inoculation, however, the expression of PR1, PDF1.2 and NPR1 weren't changed. When B. oryzae successfully infected myb73 mutant plants, the expression of PR1, PDF1.2 and NPR1 were increased. Collectively, our results suggested that MYB73 is involved in NPR1-mediated SA and JA signaling pathways.
Agricultural Sciences in China 10(5):721-727. · 0.45 Impact Factor
