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《农业科学学报》2019,18(5):1024-1034
The basidiomycetous fungus Sporisorium scitamineum causes sugarcane smut that leads to severe economic losses in the major sugarcane growing areas in China,India and Brazil,etc.Autophagy is a conserved pathway in eukaryotes for bulk degradation and cellular recycling,and was shown to be important for fungal cell growth,development,and pathogenicity.However,physiological function of autophagy has not been studied in S.scitamineum.In this study,we identified a conserved Atg8 protein,named as SsAtg8 and characterized its function.Our results showed that autophagy was blocked in the ssatg8Δ mutant,in nitrogen starvation.The ssatg8Δ mutant formed pseudohypha frequently and was hypersensitive to oxidative stress.However,mating or filamenation was unaffected in the ssatg8Δ mutant in vitro.Overall we demonstrate that autophagy is dispensable for S.scitamineum mating/filamentation,while critical for oxidative stress tolerance and proper morphology in sporidial stage.  相似文献   

3.
Autophagy is responsible for maintaining fundamental cellular homeostasis and is, therefore, essential for diverse development processes. This study reported that PoElp3, the putative catalytic subunit of Elongator complex, is involved in the maintenance of autophagy homeostasis to facilitate asexual development and pathogenicity in the rice blast fungus Pyricularia oryzae. It was found that the ΔPoelp3 strains were defective in vegetative growth, conidiation, stress response, and pathogenicity. The mutants exhibited hyper-activated autophagy in the vegetative hyphae under both nutrient-rich and nutrient-deficient conditions. The hyper-activation of autophagy possibly suppressed the production of vegetative hyphae in the ΔPoelp3 strains. Moreover, the ΔPoelp3 strains were found to be more sensitive to rapamycin during vegetative- and invasive-hyphal growth but have no effect on Target-of-Rapamycin (TOR) signaling inhibition. Taken together, these results demonstrated that PoElp3 is involved in asexual development and pathogenicity by regulating autophagy in the rice blast fungus.  相似文献   

4.
《农业科学学报》2023,22(7):2126-2137
Sugarcane smut caused by Sporisorium scitamineum is a destructive disease responsible for significant losses in sugarcane production worldwide. However, the mechanisms underlying the pathogenicity of this fungus remain largely unknown. In this study, we found that the disruption of the SsRSS1 gene, which encodes a salicylic acid (SA) sensing regulator, does not affect phenotypic traits such as the morphology, growth rate, and sexual mating ability of haploid basidiospores, but rather reduces the tolerance of basidiospores to SA stress by blocking the induction of SsSRG1, a gene encoding a SA response protein in S. scitamineum. SsRSS1 deletion resulted in the attenuation of the virulence of the fungus. In addition to a significant reduction in whip formation, a portion of plantlets (18.3%) inoculated with the ΔSsRSS1 strains were found to be infected but failed to produce whips for up to 90 days post-inoculation. However, the development of hyphae and teliospore from the ΔSsRSS1-infected plants that formed whips seemed indistinguishable from that in the wild-type-infected plants. Combined, our findings suggested that SsRss1 is required for maintaining fungal fitness in planta by counteracting SA stress.  相似文献   

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【目的】核孔蛋白Nup42在真核生物基因表达调控以及mRNA加工运输等生物学过程中发挥着重要作用,本研究旨在分析禾谷镰孢（Fusarium graminearum）中核孔蛋白基因FgNup42在病原菌生长发育、逆境胁迫、致病和产毒等生物学过程中的功能。【方法】通过融合PCR（double-joint PCR）和酵母空隙修复（gap repair）技术分别构建FgNup42基因敲除和回补载体,再利用PEG介导的原生质体转化的方法获得基因敲除突变体ΔFgNup42和回补体ΔFgNup42-C。观察测定基因敲除突变体ΔFgNup42在营养生长、无性繁殖和有性生殖过程中的变化,同时测定突变体ΔFgNup42对渗透、杀菌剂以及细胞壁胁迫因子的敏感性。将突变体ΔFgNup42进行田间麦穗和室内玉米花丝接种试验明确其致病力情况。通过液相色谱-串联质谱（LC-MS/MS）检测ΔFgNup42的产毒能力,同时利用qRT-PCR比较分析参与单端孢霉烯族毒素生物合成的7个TRI在野生型PH-1和基因敲除突变体ΔFgNup42中的相对表达量。【结果】表型测定发现,基因敲除突变体ΔFgNup42的生长速率只有野生型PH-1的50%,菌落边缘菌丝分枝变多且致密。显微观察分生孢子形成情况,发现敲除突变体ΔFgNup42相较野生型PH-1分生孢子产量降低了85.45%,并且隔膜数在0—2的分生孢子比例明显增多。有性生殖诱导结果显示ΔFgNup42的有性生殖能力增强,较野生型产生了更多的子囊壳。突变体ΔFgNup42对渗透胁迫因子NaCl和KCl,细胞壁胁迫因子刚果红,以及杀菌剂戊唑醇和氰烯菌酯的敏感性减弱。致病力分析发现敲除基因FgNup42后菌体在麦穗和玉米花丝上的致病力严重降低。此外,与野生型相比,ΔFgNup42中毒素DON、3ADON和15ADON的合成量明显减少。【结论】核孔蛋白基因FgNup42在禾谷镰孢生长发育、抵御逆境以及致病和产毒过程中发挥着重要作用。  相似文献   

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Histone lysine acetylation is catalyzed by acetyltransferases(HATs), which is important in regulating gene expression and physiological function in eukaryotic cells. HATs can be classified into two main types: A-and B-type HATs. Recently, in Fusarium graminearum, it has been reported that A-type HATs are involved in hyphal development, conidiation, sexual reproduction and virulence. However, the biological roles of B-type HATs are unknown. Here we report the identification and characterization of two B-type HATs(FgHat1 and FgHat2) in F. graminearum. Targeted deletion of FgHAT1 did not result in any detectable phenotypes. However, ΔFghat2 mutants were severely defective in vegetative growth, conidia production and morphogenesis, deoxynivalenol(DON) biosynthesis and virulence. Interestingly, deletion of Fg HAT2 resulted in significantly increased sensitivity to the DNA-damaging agent methyl methanesulfonate(MMS). Furthermore, double deletion mutants(ΔFghat1ΔFghat2) displayed similar phenotypes to the ΔFghat2 mutants. Taken together, we conclude that FgHat2 but not FgHat1 plays essential roles in regulating morphogenesis, DNA damage repair, DON production and virulence in F. graminearum.  相似文献   

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Mitogen-activated protein kinase (MAPK) cascades play an important role in extracellular signal transduction and are involved in the pathogenicity of fungal pathogens to host plants. In Curvularia lunata, the roles of two MAPK genes, Clk1 and Clm1, have already been studied. Clk1 is involved in conidia formation and pathogenicity, and Clm1 is closely related to pathogen cell wall formation and pathogenicity to maize leaves. In this study, a third C. lunata MAPK gene, Clh1, which is homologous to hog1, was successfully cloned. We found that a Clh1 deletion mutant had lower intracellular glycerol accumulation than the wild-type stain and was unable to grow normally under osmotic stress conditions. Furthermore, the deletion mutants of three C. lunata MAPK genes (Clk1, Clm1 and Clh1) had lower levels of acetyl-CoA, which is an important intermediate product in the synthesis of melanin and furan toxin, and down-regulated expression of pathogenicity-associated genes. Furthermore, pathogenicity and the ability to produce toxin were restored after adding acetyl-CoA to the culture medium, suggesting that acetyl-CoA is closely involved in the pathogen MAPK signaling pathway.  相似文献   

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Soil fungi play a very important role in the soil ecological environment. In agricultural production, long-term monoculture and continuous cropping lead to changes in fungal community diversity. However, the effects of long-term monoculture and continuous cropping on strawberry plant health and fungal community diversity have not been elucidated. In this study, using high-throughput sequencing (HTS), we compared the fungal community and diversity of strawberry rhizosphere soil after various durations of continuous cropping (0, 2, 4, 6, 8, 10 and 12 years). The results showed that soil fungal diversity increased with consecutive cropping years. Specifically, the soil-borne disease pathogens Fusarium and Guehomyces were significantly increased after strawberry continuous cropping, and the abundance of nematicidal (Arthrobotrys) fungi decreased from the fourth year of continuous cropping. The results of correlation analysis suggest that these three genera might be key fungi that contribute to the changes in soil properties that occur during continuous cropping. In addition, physicochemical property analysis showed that the soil nutrient content began to decline after the fourth year of continuous cropping. Spearman's correlation analysis showed that soil pH, available potassium (AK) and ammonium nitrogen (NH4+-N) were the most important edaphic factors leading to contrasting beneficial and pathogenic associations across consecutive strawberry cropping systems.  相似文献   

10.
Grape white rot is a destructive fungal disease occurring worldwide. Recently, Coniella vitis was identified as the predominant pathogen causing this disease in China. As the periderms of grape shoots are severely degraded by C. vitis, it was speculated that cell wall-degrading enzymes (CWDEs) might play a key role in the pathogenesis of this disease. Therefore, this study aimed to examine the hydrolytic activity of the CWDEs of C. vitis. The results showed that xylanase (Xy) and xyloglucanase (XEG) had high levels of hydrolytic activity both in vitro and in vivo. Furthermore, a high-virulence fungal strain exhibited higher levels of Xy and XEG activities compared with a low-virulence strain. The genome of the fungus was found to harbor two XEG-coding genes CvGH74A and CvGH74B, which belonged to the glycoside hydrolase (GH)74 family. The expression level of CvGH74A was found to be high during pathogen infection. CvGH74A gene deletion mutants were generated using the split-marker method. The deletion of CvGH74A decreased both the hydrolytic activities of XEG and Xy and also the ability of the fungus to infect the grape leaves. No differences in the hyphal growth, morphology of colonies, or conidiation were found between the ΔCvGH74A mutant strains and the wild-type strain. Together, these results suggested that CvGH74A acted as an important virulence factor, and its enzymatic activity might regulate the virulence of the pathogen. This study was novel in reporting that GH74 XEG acted as a virulence factor in C. vitis.  相似文献   

11.
The present study reports the sublethal effects of the entomopathogenic fungus, Aschersonia aleyrodis(Webber) on Bemisia tabaci(Gennadius)(Homoptera: Aleyrodidae). A fungal suspension of A. aleyrodis isolate Aa005 containing 1×107 conidia mL~(–1) was sprayed against B. tabaci on eggplant leaves under greenhouse conditions. The effects of fungal application on survival as well as life table parameters of the whitefly were observed at different post inoculation periods. The results indicated that A. aleyrodis can significantly affect the survival of 1st, 2nd, and 3rd nymphal instars of B. tabaci. Developmental periods of different instar nymphs were not affected by fungal application. A. aleyrodis spores persisted well and significantly affected the survivorship of young instar nymphs of B. tabaci at different post incubation periods. Life table results suggested that A. aleyrodis has no impact on general fecundity and longevity of B. tabaci. When the pathogen was exposed to the open environment and maintained for a relatively longer period, a reduction in the reproductive rate and intrinsic rate of increase was caused by the fungal spores, though the sublethal effects were not as good as the control treatment. The results suggest that the ability of spores to suppress an increase in whitefly population persists well after incubation of spores to the external environment(up to 9 days).  相似文献   

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In order to study the effects of different levels of salt stress and nitrogen(N) on physiological mechanisms,carbon isotope discrimination(△~(13)C),and yield of two wheat cultivars(cv.),a two-year field experiment was carried out during 2013-2015.The treatments included three levels of salt stress(1.3,5.2,and 10.5 dS m~(-1)),three levels of N(50,100,and 150 kg N ha~(-1)),and two wheat cultivars,Bam and Toos.Under salt stress,N application(100 and 150 kg N ha~(-1)) produced a significant effect on both cultivars with respect to physiological traits,i.e.,net photosynthetic rate(P_n),stomatal conductance(g_s),chlorophyll index(Cl),Na~+/K~+ratio as well as the grain yield(GY).The salt-tolerant and-sensitive cultivars exhibited the maximum values of physio-biochemical and yield attributes at 100 and 150 kg N ha~(-1),respectively.The results of △~(13)C showed a significant difference(P0.001) between wheat cultivars under the control and salt stress.According to our result,salt-tolerant cultivar Bam seems to be more efficient in terms of higher GY,P_n,g_s,Cl,and lower Na~+/K~+ratio as well as higher △~(13)C as compared with salt-sensitive cultivar Toos,under salt stress.Therefore,a significant positive correlation that observed between △~(13)C and GY,indicated that △~(13)C may be an effective index for indirect selection of yield potential in wheat under irrigation regimes with saline water.  相似文献   

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Dopamine plays numerous physiological roles in plants. We explored its role in the regulation of growth, nutrient absorption, and response to nitrogen (N) deficiency in Malus hupehensis Rehd. Under low N condition, plant growth slowed, and the net photosynthetic rates, chlorophyll contents, and maximal quantum yield of PSII (Fv/Fm) decreased significantly. However, the application of 100 μmol L−1 exogenous dopamine significantly reduced the inhibition of low N stress on plant growth. In addition to modifying root system architecture under low N supply, exogenous dopamine also changed the uptake, transport, and distribution of N, P, and K. Furthermore, exogenous dopamine enhances the tolerance to low nitrogen stress by increasing the activity of enzymes (nitrate reductase, nitrite reductase, glutamic acid synthase and glutamine synthetase) involved in N metabolism. We also found that exogenous dopamine promoted the expression of ethylene signaling genes (ERF1, ERF2, EIL1, ERS2, ETR1, and EIN4) under low N stress. Therefore, we hypothesized that ethylene might be involved in dopamine response to low N stress in M. hupehensis. Our results suggest that exogenous dopamine can mitigate low N stress by regulating the absorption of mineral nutrients, possibly through the regulation of the ethylene signaling pathway.  相似文献   

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采用分室培养系统,模拟正常水分和干旱胁迫两种环境条件,探讨不同丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)对紫花苜蓿(Medicago sativa L.)生长和土壤水稳性团聚体的影响.试验条件下,Glomus intraradices对苜蓿根系的侵染率均显著高于Acaulospora scrobiculata和Diversispora spurcum接种处理.正常水分条件下,供试AM真菌均能显著提高植株生物量及磷浓度.干旱胁迫显著抑制了植株生长和菌根共生体发育,总体上菌根共生体对植株生长没有明显影响,接种D.spurcum甚至趋于降低植株生物量;同时,仅有G.intraradices显著提高了植株磷浓度.AM真菌主要影响到＞2mm的水稳性团聚体数量,以G.intraradices作用效果最为显著.在菌丝室中,G.intraradices显著提高了总球囊霉素含量.研究表明AM真菌对土壤大团聚体形成具有积极作用,而菌根效应因土壤水分条件和不同菌种而异,干旱胁迫下仅有G.intraradices对土壤结构和植物生长表现出显著积极作用.在应用菌根技术治理退化土壤时,需要选用抗逆性强共生效率高的菌株,对于不同AM真菌抗逆性差异的生物学与遗传学基础尚需进一步研究.  相似文献   

16.
旨在研究苹果树腐烂病菌(Valsamali) VmImp2基因的功能,以期揭示腐烂病菌的生长发育及致病机理。利用生物信息学软件对 VmImp2进行蛋白序列及进化分析;利用Double-joint PCR和PEG介导原生质转化的方法,获得腐烂病菌 VmImp2的缺失突变体和回补菌株;利用十字交叉法以及伤口接种法,研究 VmImp2对病菌营养生长,繁殖体产生以及致病力的影响。生物信息学分析显示, VmImp2编码1 487个氨基酸,编码蛋白属于PCH(Pombe Cdc15 homology)家族,含有典型的FCH(Fes/CIP homology, F-BAR)和SH3(Src Homology 3)结构域,与梨树腐烂病菌(V.pyri)的Imp2蛋白亲缘最近。对基因进行敲除后,共获得5个缺失突变体菌株。表型分析显示,缺失突变体的营养生长受到明显影响,表现为菌丝更加稀疏,生长速率明显减缓。同时,突变体的繁殖体产生能力以及对枝条的侵染能力基本丧失。5个突变体的表型一致。将基因回补之后,共获得3个回补菌株,突变体表型缺陷基本恢复到野生型水平。说明 VmImp2基因参与苹果树腐烂病菌的营养生长、繁殖体形成以及致病过程。  相似文献   

17.
Arachidonic acid （AA or ARA）, an essential to-6 polyunsaturated fatty acid （PUFA）, can be produced by Mortierella isabellina. Mutagenesis on Mortierella isabellina As3.3410 was induced to raise ARA production. The mutant strain of YZ-124 had the highest ARA of 4.72 g. L-1, which was 5.5 times higher than that of the original strain 3.3410. mRNA expression level of △ 6- desaturase was determined in five different kinds of ARA-producing Mortierella isabellina after cultured for 7 days, and in the mutant strain YZ-124 over a 3-8 day time-course. In addition, the desaturase activity and ARA content were measured at the selected time points. The lowest expression of △6-desaturase was observed in the original strain and the highest expression in the mutant strain YZ-124, which increased with increasing time in culture. Furthermore, a positive correlation was observed between the expression levels of △6-desaturase and ARA content. Based on this, △6-desaturase played a significant role in ARA synthesis pathway in Mortierella isabellina.  相似文献   

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青蒿素是治疗疟疾的首选药物,主要从黄花蒿(Artemisia annuaL.)中提取,然而黄花蒿在生长过程中会向周围环境分泌青蒿素.为正确评估青蒿素对森林生态系统中的重要成分——外生菌根真菌的影响,试验以重庆地区有代表性的两株外生菌根真菌——褐环乳牛肝菌(Suillus luteus)Sl 8和松乳菇(Lactarius delicious)Ld3为材料,研究了青蒿素对菌丝生长,H+和有机酸分泌,以及养分吸收的影响.结果表明,在液体培养基中加入青蒿素,外生菌根真菌的生长受到明显抑制,菌丝生物量降幅高达26.89％(Ld3)和89.13％ (Sl 8);Ld3分泌H+和草酸的能力增强,而Sl8分泌量下降.随着青蒿素浓度的增加,菌丝的N、P、K含量及吸收量显著减少.当培养基中青蒿素达到80 mg/L时,Ld3的N、P、K吸收量比不加青蒿素的处理分别降低了50.55％、46.30％和42.28％;Sl8几乎丧失对N、P、K的吸收能力.说明青蒿素不同程度地抑制了外生菌根真菌的生长和养分吸收,但对H+和草酸的分泌作用因菌株不同而异.  相似文献   

19.
Lipoxygenase (LOXs) is a kind of dioxygenase without heme and iron, which plays an important role in the development and adaptation of many plants to the environment. However, the study of strawberry LOX gene family has not been reported. In this study, 14 LOX genes were identified from the diploid woodland strawberry genome. The phylogenetic tree divides the FvLOX gene into two subfamilies: 9-LOX and 13-LOX. Gene duplication event analysis showed that whole-genome duplication (WGD)/segmental duplication and dispersed duplication effectively promoted the expansion of strawberry LOX family. QRT-PCR analysis showed that FvLOX genes were expressed in different tissues. Expression profile analysis showed that FvLOX1 and FvLOX8 were up-regulated under low temperature stress, FvLOX3 and FvLOX7 were up-regulated under drought stress, FvLOX6 and FvLOX9 were up-regulated under salt stress, FvLOX2, FvLOX3 and FvLOX6 were up-regulated under salicylic acid (SA) treatment, FvLOX3, FvLOX11 and FvLOX14 were up-regulated under methyl jasmonate (MeJA) treatment, FvLOX4 and FvLOX14 were up-regulated under abscisic acid (ABA) treatment. Promoter analysis showed that FvLOX genes were involved in plant growth and development and stress response. We analyzed and identified the whole genome of strawberry FvLOX family and characterized a variety of FvLOX candidate genes involved in abiotic stress response. This study laid a theoretical and empirical foundation for the response mechanism of strawberry to abiotic stress.  相似文献   

20.
Jojoba (Simmondsia chinensis) is mainly distributed in desert, and the molecular mechanisms of jojoba in response to abiotic stress still remain elusive. In this paper, we cloned and characterized a SOD gene from jojoba named as ScMnSOD, and introduced into Arabidopsis to investigate its functions of responding to drought stress. The transgenic Arabidopsis showed an improvement in drought tolerance. Moreover, under a water deficit condition, the accumulation of reactive oxygen species (ROS) was remarkably decreased in the transgenic lines compared to the WT. Furthermore, the ScMnSOD promoter was cloned to the 5′-upstream of GUS coding region in a binary vector, and introduced into Arabidopsis. And results showed that ScMnSOD expression can be induced by drought, salt, ABA, and low temperature. In conclusion, ScMnSOD plays an important role in drought tolerance which is, at least partially, attributed to its role in ROS detoxification.  相似文献   

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