scholarly journals Comparison of Four Systems to Test the Tolerance of ‘Fortune’ Mandarin Tissue Cultured Plants to Alternaria alternata

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1321
Author(s):  
Margarita Pérez-Jiménez ◽  
Olaya Pérez-Tornero
Keyword(s):  
Culture Filtrate ◽  
Alternaria Alternata ◽  
In Vitro Selection ◽  
Culture Media ◽  
Severe Disease ◽  
Mutation Breeding ◽  
Brown Spot ◽  
Fungus Culture ◽  
Alternaria Brown Spot

Alternaria brown spot is a severe disease that affects leaves and fruits on susceptible mandarin and mandarin-like cultivars, and is produced by Alternaria alternata. Consequently, there is an urge to obtain new cultivars resistant to A. alternata, and mutation breeding together with tissue culture can help shorten the process. However, a protocol for the in vitro selection of resistant citrus genotypes is lacking. In this study, four methods to evaluate the sensitivity to Alternaria of mandarin ‘Fortune’ explants in in vitro culture were tested. The four tested systems consisted of: (1) the addition of the mycotoxin, produced by A. alternata in ‘Fortune’, to the propagation culture media, (2) the addition of the A. alternata culture filtrate to the propagation culture media, (3) the application of the mycotoxin to the intact shoot leaves, and (4) the application of the mycotoxin to the previously excised and wounded leaves. After analyzing the results, only the addition of the A. alternata culture filtrate to the culture media and the application of the mycotoxin to the wounded leaves produced symptoms of infection. However, the addition of the fungus culture filtrate to the culture media produced results, which might indicate that, in addition to the mycotoxin, many other unknown elements that can affect the plant growth and behavior could be found in the fungus culture filtrate. Therefore, the application of the toxin to the excised and wounded leaves seems to be the most reliable method to analyze sensitivity to Alternaria of ‘Fortune’ explants cultured in vitro.

scholarly journals Response of citrus hybrids to Alternaria alternata inoculation

2020 ◽  
Vol 11 ◽  
pp. e3358
Author(s):  
Gabriela Da Costa ◽  
Maiara Curtolo ◽  
Thaís Cavichioli Magni ◽  
Mariângela Cristofani-Yaly
Keyword(s):  
Alternaria Alternata ◽  
Sweet Orange ◽  
Brown Spot ◽  
Limiting Factor ◽  
Alternaria Brown Spot ◽  
In Vitro Inoculation ◽  
Citrus Orchards ◽  
Citrus Hybrids ◽  
Selection Of

Citrus orchards have some limitations, such as the occurrence of phytosanitary problems. Alternaria brown spot (ABS) is caused by fungus Alternaria alternata, which affects several parts of the plant by producing a host-specific toxin, known as ACT. ABS is a limiting factor in orchards due to the susceptibility of most planted cultivars: ‘Murcott’ tangor and ‘Ponkan’ tangerine. The selection of varieties resistant/tolerant to the disease has economic importance. Therefore, the aim of this experiment was to evaluate the response to A. alternata inoculation in a population of ‘Murcott’ tangor vs ‘Pera’ sweet orange hybrids. Leaves of 2-3 centimeters in length of ‘Murcott’ tangor, ‘Pera’ sweet orange, ‘Ponkan’, ‘Dancy’, ‘Fremont’ tangerine and 198 hybrids were collected. For in vitro inoculation, monosporic A. alternata culture at concentration of 105 conidia mL-1 was used. Inoculated leaves were stored in humid chamber. After 24, 48 and 72 hours of inoculation, leaf lesions were evaluated following a diagrammatic scale. The results obtained showed that most hybrids from the crossing of ‘Murcott’ tangor vs ‘Pera’ sweet orange are susceptible to ABS. However, 44 are resistant and ten are tolerant. Among ABS-tolerant hybrids, some have phenotype similar to that of cultivated and commercialized hybrids.

scholarly journals Seleksi In Vitro dan Pengujian Mutan Tanaman Pisang Ambon Kuning untuk Ketahanan terhadap Penyakit Layu Fusarium

2016 ◽  
Vol 9 (2) ◽  
pp. 66
Author(s):  
Deden Sukmadjaja ◽  
Ragapadmi Purnamaningsih ◽  
Tri P. Priyatno
Keyword(s):  
Fusarium Wilt ◽  
In Vitro Selection ◽  
Fusaric Acid ◽  
Mutation Breeding ◽  
Induce Mutagenesis ◽  
Fusarium Wilt Of Banana ◽  
Basal Media ◽  
Generative Phase ◽  
Race 4

<p>Fusarium wilt of banana (Musa spp.) caused by<br />Fusarium oxysporum f. sp. cubense (Foc) is the most serious<br />problem faced in banana cultivation in terms of plant<br />productivity and fruit quality. Mutation breeding is one of the<br />alternative method that can be applied in producing new<br />banana cultivar. Mutants can be induced by chemical<br />mutagen such as ethyl methane sulfonate (EMS) followed by<br />in vitro selection and then evaluation of the mutants to<br />fusarium wilt disease in glasshouse and Foc infected field.<br />The aim of this research was obtained EMS induced and in<br />vitro selected mutants of banana var. Ambon Kuning and<br />evaluated Foc disease resistant clones in glasshouse and<br />Foc infected field. The first step to obtain the explants for<br />this research was initiation and formation of multiple bud<br />clumps (MBC) using MS basal media supplemented with 5,<br />10, and 20 mg/l of benzyladenin. Plant regeneration of MBC<br />was also studied by using MS media containing 0, 0.2, and 1<br />mg/l of benzyladenin. To induce mutagenesis, MBC was<br />soaked in 0.1, 0.3, and 0.5% (v/v) EMS for 1, 2, and 3 hours.<br />The assesment of resistant MBC mutants to Fusarium<br />phytotoxin was conducted by using fusaric acid (FA) as<br />selection agent in concentration of 30, 45, and 60 ppm.<br />Putative mutant plants produced by in vitro selection were<br />further tested using spore solution of Foc race 4 in<br />glasshouse. Meanwhile, Foc resistance assesment in the<br />infected field was conducted in Pasirkuda Experimental<br />Station, Bogor Agricultural University. The results showed<br />that MBC can be formed in MS basal media supplemented<br />with 10 or 20 mg/l benzyladenin. The EMS played a role in<br />obtaining mutants by producing 68 MBC putative mutants<br />tolerant to Foc based on FA selection. Further evaluation in<br />the glasshouse was obtained 64 Foc resistant plants from<br />391 putative mutants produced by in vitro selection.<br />Evaluation in the Foc infected field showed six clones<br />survived until generative phase (12 month of age).</p>

scholarly journals Role of the Host-Selective ACT-Toxin Synthesis Gene ACTTS2 Encoding an Enoyl-Reductase in Pathogenicity of the Tangerine Pathotype of Alternaria alternata

2010 ◽  
Vol 100 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Naoya Ajiro ◽  
Yoko Miyamoto ◽  
Akira Masunaka ◽  
Takashi Tsuge ◽  
Mikihiro Yamamoto ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Essential Gene ◽  
Toxin Production ◽  
Brown Spot ◽  
Gene Encoding ◽  
Bac Clone ◽  
Biosynthesis Gene Cluster ◽  
Enoyl Reductase ◽  
Alternaria Brown Spot ◽  
Rapid Amplification

The tangerine pathotype of Alternaria alternata produces host-selective ACT-toxin and causes Alternaria brown spot disease of tangerines and tangerine hybrids. Sequence analysis of a genomic BAC clone identified a previously uncharacterized portion of the ACT-toxin biosynthesis gene cluster (ACTT). A 1,034-bp gene encoding a putative enoyl-reductase was identified by using rapid amplification of cDNA ends and polymerase chain reaction and designated ACTTS2. Genomic Southern blots demonstrated that ACTTS2 is present only in ACT-toxin producers and is carried on a 1.9 Mb conditionally dispensable chromosome by the tangerine pathotype. Targeted gene disruption of ACTTS2 led to a reduction in ACT-toxin production and pathogenicity, and transcriptional knockdown of ACTTS2 using RNA silencing resulted in complete loss of ACT-toxin production and pathogenicity. These results indicate that ACTTS2 is an essential gene for ACT-toxin biosynthesis in the tangerine pathotype of A. alternata and is required for pathogenicity of this fungus.

IN VITRO SELECTION FOR FUSARIUM RESISTANT ORIENTAL LILY MUTANTS USING CULTURE FILTRATE OF THE FUNGAL AGENT

2014 ◽  
pp. 205-212 ◽  
Author(s):  
Y.P. Zhang ◽  
S. Jiang ◽  
S.P. Qu ◽  
X.M. Yang ◽  
X.N. Wang ◽  
...  
Keyword(s):  
Culture Filtrate ◽  
In Vitro Selection ◽  
Selection For ◽  
Oriental Lily

IN VITRO SELECTION OF APPLE ROOTSTOCK SOMACLONES WITH PHYTOPHTHORA CACTORUM CULTURE FILTRATE

1990 ◽  
pp. 409-416 ◽  
Author(s):  
P. ROSATI ◽  
B. MEZZETTI ◽  
M. ANCHERANI ◽  
S. FOSCOLO ◽  
S. PREDIERI ◽  
...  
Keyword(s):  
Culture Filtrate ◽  
In Vitro Selection ◽  
Phytophthora Cactorum ◽  
Apple Rootstock ◽  
Selection Of

Sensitivity of Alternaria alternata from Citrus to Boscalid and Polymorphism in Iron-Sulfur and in Anchored Membrane Subunits of Succinate Dehydrogenase

Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 231-239 ◽  
Author(s):  
Byron Vega ◽  
Megan M. Dewdney
Keyword(s):  
Succinate Dehydrogenase ◽  
Alternaria Alternata ◽  
Mycelial Growth ◽  
Conidial Germination ◽  
Brown Spot ◽  
Sequence Comparisons ◽  
Sensitivity Tests ◽  
Alternaria Brown Spot ◽  
Succinate Dehydrogenase Inhibitor

Boscalid, a succinate dehydrogenase inhibitor (SDHI), was registered in 2011 to control Alternaria brown spot (ABS) of citrus, caused by Alternaria alternata. In this study, the effect of boscalid on mycelial growth, conidial germination, and resazurin reduction was established in a subset of 16 sensitive isolates using three different media. Conidial germination and mycelial growth inhibition were not suppressed even at higher concentrations of boscalid, although effective concentration to inhibit 50% growth (EC50) values were established with each method. Resazurin reduction produced the lowest EC50 values and was selected for further sensitivity tests. In total, 419 isolates, never exposed to boscalid and collected from Florida tangerine orchards between 1996 to 2012, were tested for boscalid sensitivity. The sensitivity distribution was a unimodal curve with a mean EC50 value of 0.60 μg/ml and a range of 0.07 to 5.84 μg/ml. The molecular characterization of the succinate dehydrogenase (SDH) genes were also determined in a subset of 15 isolates, exhibiting great variability in boscalid sensitivity, by cloning and sequencing the sdhB, sdhC, and sdhD genes. Sequence comparisons of the SDH complex revealed the presence of mutations in 14 of 15 isolates. In total, 21 mutations were identified. Double and multiple mutations were observed in SDHC and SDHD, respectively. In SDHB, 4 mutations were observed while, in SDHC and SDHD, 5 and 12 mutations were detected, respectively. No mutations were found in the highly conserved histidine residues at positions 277 in SDHB, 134 in SDHC, and 133 in SDHD, typically observed in SDHI-resistant isolates. Our findings suggest that A. alternata populations from Florida are sensitive to boscalid and it could be used in ABS spray programs. Boscalid resistance is currently not a problem, although further monitoring for resistance is advisable.

Evaluation of drought resistance-related traits in durum wheat somaclonal lines selected in vitro

2004 ◽  
Vol 44 (1) ◽  
pp. 27 ◽  
Author(s):  
M. Bajji ◽  
P. Bertin ◽  
S. Lutts ◽  
J-M. Kinet
Keyword(s):  
Durum Wheat ◽  
Somaclonal Variation ◽  
Drought Resistance ◽  
In Vitro Selection ◽  
Culture Media ◽  
Field Studies ◽  
Resistance Mechanisms ◽  
Wide Range ◽  
Triticum Durum Desf

Somaclonal variation associated with in vitro selection has been used as a source of variability to improve drought resistance of 3 durum wheat (Triticum durum Desf.) cultivars (Selbera, Sebou, and Kyperounda). In a previous study, R0 plants with improved drought resistance-related characters were regenerated after selection on culture media containing polyethylene glycol (PEG). This improvement was transmitted to the R1 progeny. The present study analysed the behaviour of the selected tissue culture-derived lines in subsequent R2, R3 and R4�generations. Differences in electrolyte leakage, chlorophyll fluorescence (Fv/Fm), stomatal conductance and days to heading were found between the parental cultivars and most of their in vitro-derived lines. The changes may differ from one cultivar to another. Many promising somaclonal lines still presented improvement for at least 3 of the 4�parameters measured comparatively to initial cultivars. Somaclonal variation thus appears to induce a wide range of modifications among individual components of drought-resistance mechanisms. These improved traits could be valuable if shown to be inherited and to give enhanced agronomic performances in future field studies.

scholarly journals Temperature, Leaf Wetness, and Isolate Effects on Infection of Minneola Tangelo Leaves by Alternaria sp.

Plant Disease ◽  
1999 ◽  
Vol 83 (5) ◽  
pp. 429-433 ◽  
Author(s):  
Y. Canihos ◽  
T. L. Peever ◽  
L. W. Timmer
Keyword(s):  
Polynomial Equation ◽  
Brown Spot ◽  
Effect Of Temperature ◽  
Leaf Wetness ◽  
Significant Difference ◽  
Alternaria Brown Spot ◽  
Detached Leaves ◽  
Alternaria Sp ◽  
Response To Temperature

Alternaria brown spot causes necrotic lesions on immature leaves, twigs, and fruit of tangerines and their hybrids, reducing yield and fruit quality. The effect of temperature, leaf wetness, and isolate was evaluated in an in vitro system using immature detached leaves of Minneola tangelo Infection was greatest at 27°C, decreased gradually as the temperature declined to 24, 20, and 17°C, and dropped sharply at 32°C. Levels of infection were low at 4 and 8 h of leaf wetness and continued to increase with longer wetting periods up to 36 h. A polynomial equation was developed that provided a good fit for the data (adjusted R2 = 0.93). Isolates differed in aggressiveness, but there was no significant difference among isolates in their response to temperature and leaf wetness duration.

scholarly journals Chromosome-scale genome sequence of Alternaria alternata causing Alternaria brown spot of citrus

2021 ◽  
Author(s):  
Yunpeng Gai ◽  
Haijie Ma ◽  
Yanan Chen ◽  
Lei Li ◽  
Yingze Cao ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Genome Assembly ◽  
Alternaria Alternata ◽  
Draft Genome ◽  
Gc Content ◽  
Brown Spot ◽  
Toxin Gene ◽  
Alternaria Brown Spot ◽  
Alternaria Species ◽  
Chromosome Level

Alternaria brown spot (ABS) caused by Alternaria alternata is an economically important fungal disease of citrus worldwide. The ABS pathogen A. alternata tangerine pathotype can produce a host-specific ACT toxin, which is regulated by ACT toxin gene cluster located in the conditionally dispensable chromosome (CDC). Previously, we have assembled a draft genome of A. alternata tangerine pathotype strain Z7, which comprises 165 contigs. In this study, we report a chromosome-level genome assembly of A. alternata Z7 through the combination of Oxford nanopore sequencing and Illumina sequencing technologies. The assembly of A. alternata Z7 had a total size of 34.28 Mb, with a GC content of 51.01% and contig N50 of Mb. The genome is encompassed 12067 protein-coding genes, 34 rRNAs, and 107 tRNAs. Interestingly, A. alternata Z7 is composed of 10 essential chromosomes (ECs) and 2 conditionally dispensable chromosomes (CDCs), which is consistent with the experimental evidences of pulsed-field gel electrophoresis (PFGE). To our best knowledge, this is the first chromosome-level genome assembly of A. alternata. In addition, a database for citrus-related Alternaria genomes has been established to provide public resources for the sequences, annotation and comparative genomics data of Alternaria species. The improved genome sequence and annotation at the chromosome level is a significant step toward a better understanding of the pathogenicity of A. alternata. The database will be updated regularly whenever the genomes of newly isolated Alternaria species are available. The citrus-related Alternaria genomes database is open accessible through http://www.zjudata.com/alternaria/blast.php.

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