scholarly journals Biological and Transcriptomic Characterization of Pre-haustorial Resistance to Sunflower Broomrape (Orobanche cumana W.)

2021 ◽  
Author(s):  
Dana Sisou ◽  
Yaakov Tadmor ◽  
Dina Plakhine ◽  
Sariel Hübner ◽  
Hanan Eizenberg

AbstractInfestations with sunflower broomrape (Orobanche cumana Wallr.), an obligatory root parasite, constitute a major limitation to sunflower production in many regions around the world. Breeding for resistance is the most effective approach to reduce sunflower broomrape infestation, yet resistance mechanisms are often overcome by new races of the pathogen. Elucidating the mechanisms controlling the resistance to broomrape at the molecular level is thus the most desirable pathway to obtaining long-lasting resistance and reducing yield loss in sunflower. In this study, we investigated broomrape resistance in a confectionery sunflower hybrid with a robust and long-lasting resistance to sunflower broomrape. Visual screening and histological examination of sunflower roots revealed that penetration of the intrusive broomrape cells into the host root endodermis is blocked at the host cortex, indicating a pre-haustorial mechanism of resistance. A comparative RNA-Seq experiment conducted between roots obtained from the resistant cultivar, a bulk of five broomrape resistant lines and a bulk of five broomrape susceptible lines allowed the identification of genes that were significantly differentially expressed upon broomrape infestation. Among these differentially expressed genes, β-1,3-endoglucanase, β-glucanase and ethylene-responsive transcription factor4 (ERF4) genes were identified. These genes were previously reported to be pathogenesis-related genes in other plant species. This genetics investigation together with the histological examinations led us to conclude that the resistance mechanism involves the identification of the broomrape and the consequent formation of a physical barrier that prevents the penetration of the broomrape into the sunflower roots.

Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1810
Author(s):  
Dana Sisou ◽  
Yaakov Tadmor ◽  
Dina Plakhine ◽  
Hammam Ziadna ◽  
Sariel Hübner ◽  
...  

Infestations with sunflower broomrape (Orobanche cumana Wallr.), an obligatory root parasite, constitute a major limitation to sunflower production in many regions around the world. Breeding for resistance is the most effective approach to reduce sunflower broomrape infestation, yet resistance mechanisms are often broken by new races of the pathogen. Elucidating the mechanisms controlling resistance to broomrape at the molecular level is, thus, a desirable way to obtain long-lasting resistance. In this study, we investigated broomrape resistance in a confectionery sunflower cultivar with a robust and long-lasting resistance to sunflower broomrape. Visual screening and histological examination of sunflower roots revealed that penetration of the broomrape haustorium into the sunflower roots was blocked at the cortex, indicating a pre-haustorial mechanism of resistance. A comparative RNA sequencing between broomrape-resistant and -susceptible accessions allowed the identification of genes that were significantly differentially expressed upon broomrape infestation. Among these genes were β-1,3-endoglucanase, β-glucanase, and ethylene-responsive transcription factor 4 (ERF4). These genes were previously reported to be pathogenesis-related in other plant species. This transcriptomic investigation, together with the histological examinations, led us to conclude that the resistance mechanism involves the identification of the broomrape and the consequent formation of a physical barrier that prevents the establishment of the broomrape into the sunflower roots.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shixing Liu ◽  
Renchi Fang ◽  
Ying Zhang ◽  
Lijiang Chen ◽  
Na Huang ◽  
...  

Abstract Background The emergence of carbapenem-resistant and colistin-resistant ECC pose a huge challenge to infection control. The purpose of this study was to clarify the mechanism of the carbapenems and colistin co-resistance in Enterobacter cloacae Complex (ECC) strains. Results This study showed that the mechanisms of carbapenem resistance in this study are: 1. Generating carbapenemase (7 of 19); 2. The production of AmpC or ESBLs combined with decreased expression of out membrane protein (12 of 19). hsp60 sequence analysis suggested 10 of 19 the strains belong to colistin hetero-resistant clusters and the mechanism of colistin resistance is increasing expression of acrA in the efflux pump AcrAB-TolC alone (18 of 19) or accompanied by a decrease of affinity between colistin and outer membrane caused by the modification of lipid A (14 of 19). Moreover, an ECC strain co-harboring plasmid-mediated mcr-4.3 and blaNDM-1 has been found. Conclusions This study suggested that there is no overlap between the resistance mechanism of co-resistant ECC strains to carbapenem and colistin. However, the emergence of strain co-harboring plasmid-mediated resistance genes indicated that ECC is a potential carrier for the horizontal spread of carbapenems and colistin resistance.


Author(s):  
Alessandro Tubita ◽  
Ignazia Tusa ◽  
Elisabetta Rovida

Molecularly tailored therapies have opened a new era, chronic myeloid leukemia being the ideal example, in the treatment of cancer. However, available therapeutic options are still unsatisfactory in many types of cancer, and often fail due to the occurrence of resistance mechanisms. With regard to small-molecule compounds targeting the components of the Mitogen-Activated Protein Kinase (MAPK) cascade RAF-MEK1/2-ERK1/2, these drugs may result ineffective as a consequence of the activation of compensatory pro-survival/proliferative signals, including receptor tyrosine kinases, PI3K, as well as other components of the MAPK family such as TPL2/COT. The MAPK ERK5 has been identified as a key signaling molecule in the biology of several types of cancer. In this review, we report pieces of evidence regarding the activation of the MEK5-ERK5 pathway as a resistance mechanism to RAF-MEK1/2-ERK1/2 inhibitors. We also highlight the known and possible mechanisms underlying the cross-talks between the ERK1/2 and the ERK5 pathways, the characterization of which is of great importance to maximize, in the future, the impact of RAF-MEK1/2-ERK1/2 targeting. Finally, we emphasize the need of developing additional therapeutically relevant MEK5-ERK5 inhibitors to be used for combined treatments, thus preventing the onset of resistance to cancer therapies relying on RAF-MEK1/2-ERK1/2 inhibitors.


2020 ◽  
Vol 8 (2) ◽  
pp. 278 ◽  
Author(s):  
Weiyan Wang ◽  
Xiao Liu ◽  
Tao Han ◽  
Kunyuan Li ◽  
Yang Qu ◽  
...  

Metalaxyl is one of the main fungicides used to control pepper blight caused by Phytophthora capsici. Metalaxyl resistance of P. capsici, caused by the long-term intense use of this fungicide, has become one of the most serious challenges facing pest management. To reveal the potential resistance mechanism of P. capsici to fungicide metalaxyl, a metalaxyl-resistant mutant strain SD1-9 was obtained under laboratory conditions. The pathogenicity test showed that mutant strain SD1-9 had different pathogenicity to different host plants with or without the treatment of metalaxyl compared with that of the wild type SD1. Comparative transcriptome sequencing of mutant strain SD1-9 and wild type SD1 led to the identification of 3845 differentially expressed genes, among them, 517 genes were upregulated, while 3328 genes were down-regulated in SD1-9 compared to that in the SD1. The expression levels of 10 genes were further verified by real-time RT-PCR. KEGG analysis showed that the differentially expressed genes were enriched in the peroxisome, endocytosis, alanine and tyrosine metabolism. The expression of the candidate gene XLOC_020226 during 10 life history stages was further studied, the results showed that expression level reached a maximum at the zoospores stage and basically showed a gradually increasing trend with increasing infection time in pepper leaves in SD1-9 strain, while its expression gradually increased in the SD1 strain throughout the 10 stages, indicated that XLOC_020226 may be related to the growth and pathogenicity of P. capsici. In summary, transcriptome analysis of plant pathogen P. capsici strains with different metalaxyl resistance not only provided database of the genes involved in the metalaxyl resistance of P. capsici, but also allowed us to gain novel insights into the potential resistance mechanism of P. capsici to metalaxyl in peppers.


2019 ◽  
Author(s):  
Jun Feng ◽  
Min Zhang ◽  
Kangning Yang ◽  
Wenting You ◽  
Caixia Zheng

Abstract Background Podosphaera aphanis , a predominately biotrophic fungal pathogen, causes significant yield losses of strawberry. China is the largest strawberry producer in the world, and selecting for powdery mildew-resistant cultivars is desirable. However, the resistance mechanism against P. aphanis in the octoploid strawberry remains unclear. Results To understand the molecular resistance mechanisms, we inoculated strawberry with P. aphanis , and examined the expression profiles of candidate genes and the biochemical phenotypes in strawberry leaves of two groups. The unigenes obtained from salicylic acid (SA)-untreated (SA–) and treated (SA+) leaves resulted in a total of 48,020 and 45,896 genes, respectively. KEGG enrichment showed that phenylpropanoid biosynthesis, plant–pathogen interaction, and plant hormone signal transduction pathways were enriched to a noticeable extent. Comparative analysis demonstrated that genes associated with the SA signalling pathway were significantly upregulated in the strawberry– P. aphanis interaction. In particular, the genes FaTGA , FaDELLA , and FaJAZ negatively regulating salicylic acid SA-responsive genes, whereas FaNPR1 , FaWRKY33 , FaWRKY70 , and FaMYC2 positively regulated SA-responsive genes, leading to increased expression of SA-responsive genes compared to a significant decline in expression of jasmonic acid-responsive genes. Conclusions This study describes the role of total flavonoid content, proanthocyanidins (PAs), pathogenesis-related (PR) proteins, SA, and transcription factors in regulatory model against P. aphanis , which coincided with an early activation of defence, leading to the accumulation of PAs and the production of PR proteins.


2021 ◽  
Vol 13 (13) ◽  
pp. 7003
Author(s):  
Andrea Milani ◽  
Silvia Panozzo ◽  
Silvia Farinati ◽  
Duilio Iamonico ◽  
Maurizio Sattin ◽  
...  

Amaranthus palmeri S. Watson (Amaranthaceae Juss.) is a dioecious noxious weed, native to the Americas, which infests summer crops. It causes high crop losses, and rapidly evolves resistance to herbicides. In Europe, A. palmeri was recorded mostly as a casual alien, but in 2018 it was reported infesting a soybean field in Italy, and the next year two more populations were found in the same area. Experiments were conducted on these three populations to evaluate the resistance to ALS-inhibiting herbicides, to determine the main resistance mechanisms involved and assess the efficacy of alternative herbicides with different sites of action than ALS. The three populations were confirmed cross-resistant to ALS-inhibiting herbicides (thifensulfuron-methyl and imazamox). Gene sequencing identified a Trp to Leu substitution at position 574 of ALS gene in resistant plants, proving that the main resistance mechanism for the three populations is target-site related. The presence of other resistance mechanisms cannot be excluded. Metobromuron, metribuzin and glyphosate are still effective on these populations.


Weed Science ◽  
2019 ◽  
Vol 68 (2) ◽  
pp. 134-142
Author(s):  
Evgenia Dor ◽  
Dina Plakhine ◽  
Daniel M. Joel ◽  
Hailey Larose ◽  
James H. Westwood ◽  
...  

AbstractBroomrapes (Orobanche and Phelipanche species, Orobanchaceae) are obligate root parasites of dicotyledonous plants. This taxonomic group includes seven weedy parasites of agricultural crops that damage vegetables, sunflower (Helianthus annuus L.), and legumes. Processing-tomato (Solanum lycopersicum L.) fields in Israel have been recently found infested with a new broomrape, first identified as nodding broomrape (Orobanche cernua Loefl.) based on its host. However, its morphology resembled the closely related sunflower broomrape (Orobanche cumana Wallr.), an obligate parasite of sunflower. The new race (CUCE) parasitized sunflower, tomato, and tobacco (Nicotiana tabacum L.) in vitro, in a polyethylene bag system and in pots. Its seeds germinated in response to strigolactones (orobanchol, 5-deoxystrigol, 2′-epiorobanchol, and GR24) and dehydrocostus lactone (DCL), whereas O. cumana seeds responded only to DCL and GR24, and O. cernua only to strigolactones. Based on morphological similarities with O. cumana, shared molecular markers with O. cumana, ability to parasitize sunflower and respond to sunflower-germination stimulants, it was concluded that CUCE is a new race of O. cumana, with a host range expanding to Solanaceae crops. While being an important noxious weed of sunflower, this new O. cumana race is currently spreading and posing a threat to processing tomato in Israel. This finding is an alarming indication that broomrapes can shift host range and that similar new races of O. cumana could potentially appear in other countries.


2021 ◽  
Author(s):  
Chris Parker

Abstract O. cumana is an obligatory, non-photosynthetic root parasite. It is believed to have evolved relatively recently from forms of O. cernua parasitizing wild Asteraceae, in particular species of Artemisia, and transferring to cultivated Helianthus annuus (sunflower). O. cumana is thought to be native to Eastern Europe (Russia) and has subsequently spread to most other sunflower growing regions of central and western Europe and Asia. The absence of O. cumana in sunflower growing regions of South America (for example Argentina) is believed to be associated with warmer winter temperatures not suitable for this species, rather than the seeds not being present. O. cumana can cause immense damage to cultivated sunflowers resulting in a significant decrease in yield. Despite resistant sunflower varieties being developed more virulent races of O. cumana have repeatedly evolved, or been selected, to overcome resistance. Thus, in spite of constant breeding efforts, losses continue in established sunflower growing areas and there is potential for it to invade new areas, wherever sunflower is grown.


2013 ◽  
Vol 48 (3) ◽  
pp. 295-302
Author(s):  
Lei Zhenzhen ◽  
Ye Jinglong ◽  
Cheng Haili ◽  
Chen Yun ◽  
Wang Huixing ◽  
...  

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